phan tich cac chi tieu moi truong - ts dinh hai ha

7/31/2019 Phan Tich Cac Chi Tieu Moi Truong - TS Dinh Hai Ha

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B CNG THNGI HC CNG NGHIP THNH PH H CH MINH

VIN KHOA HC CNG NGH & QUN L MI TRNG

PHNG PHAP PHAN TCH CAC CHTIEU MOI TRNG

ThS. INH HAI HA

TP.HO CH MINH,thang 09 nam 2009(Cp nht ln 3)


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Phng phap phan tch cac ch tieu moi trng - ThS. inh Hai Ha

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LI NOI AU

Kinh te cang phat trien keo theo o nhiem moi trng ngay cang nhieu. Neu nhchung ta khong co nhng chnh sach phat trien ben vng phat trien kinh te i oivi bao ve moi trng th the he tng lai cua chung ta se phai ganh chu nhng hauqua nang ne nh thien tai, lu lut do thay oi kh hau toan cau, cac can benh ung th

ngay cang nhieu do cac chat thai oc hai c thai ra moi trng mot cach tuy tien,s suy giam tang ozon... Hien nay co rat nhieu nha may, khu cong nghiep hang ngaythai ra moi trng hang tram khoi nc thai gay o nhiem moi trng. Nham anhgia mc o o nhiem do cac hoat ong nay gay nen t o a ra hng x ly thchhp, sach Phng Phap Phan Tch Cac Ch Tieu Moi Trng cung cap cac kien thccho ngi ky s moi trng kha nang anh gia chat lng nguon nc va at tai khuvc o.

Ngoai ra sach Phng Phap Phan Tch Cac Ch Tieu Moi Trng con co the sdung cho mon hoc Thc Hanh Hoa Ky Thuat Moi Trng va Thc Hanh MoiTrng at, thc hanh O Nhiem Khong Kh dung cho sinh vien thuoc cac chuyennganh nh Cong nghe Moi trng, Quan ly Moi trng, Khoa hoc Moi trng trongcac trng Cao ang va ai hoc trong ca nc cung nh cho cac can bo thuoc cactrung tam nghien cu, phan tch chat lng nc va at, cac phong th nghiem cuacac khu cong nghiep

e hoan thanh cuon sach tac gia a tham khao nhieu nguon tai lieu khac nhau, xinc chan thanh gi li cam n en cac nha khoa hoc, ac biet la cac thay co thuocKhoa Cong nghe Moi trng trng ai hoc Dan Lap Van Lang tp. HCM t

nhng nam 1998 a phien dch t tai lieu nc ngoai Standard Methods e cungcap cac nguon d lieu qu gia giup tac gia co the hoan thanh cuon sach nay.

Rat mong nhan c y kien ong gop e lan xuat ban sau c hoan thien hn.Moi y kien ong gop xin gi ve a [email protected]

Xin chan thanh cam n.

Tac gia


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MUC LUC

Chng 1: M au ....................................................................................................... 5Bai 1: Lay mau va bao quan mau ................................................................................ 5Bai 2: Dung dch chuan .............................................................................................. 16

Chng 2: Phan tch cac thong so vat ly ................................................................ 22Bai 3: pH, EC, o man ................................................................................................ 22Bai 4: Chat ran ............................................................................................................ 23Bai 5: o uc .............................................................................................................. 25Bai 6: o mau ............................................................................................................. 26

Chng 3: Phan tch cac thong so the tch ............................................................ 28Bai 7: Chloride ............................................................................................................ 28Bai 8: o acid ............................................................................................................. 30

Bai 9: o kiem ............................................................................................................ 32Bai 10: o cng tong cong ......................................................................................... 34Bai 11: o cng calci ................................................................................................. 38Bai 12: Nitrogen organic ......................................................................................... 39

Chng 4: Phan tch cac thong so trac quang ....................................................... 42Bai 13: Sat ................................................................................................................... 42Bai 14: Nitrogen nitrite (N-NO2-) ............................................................................ 45Bai 15: Nitrogen-nitrate (NO3-) .................................................................................. 48

Bai 16: Nitrogen ammonia (NH3) ............................................................................ 50Bai 17: Phosphate ....................................................................................................... 54Bai 18: Sunfat .............................................................................................................. 57Bai 19: Mangan ........................................................................................................... 59Bai 20: Chlorine Cl2 .................................................................................................. 61

Chng 5: Phan tch cac thong so sinh hoa ........................................................... 62Bai 21: Oxi hoa tan (DO) .......................................................................................... 62Bai 22: Nhu cau oxy sinh hoc (biological oxygen demand BOD) ......................... 65Bai 23: Nhu cau oxi hoa hoc (chemical oxygen demand COD) ............................ 68

Chng 6: Phng phap phan tch cac ch tieu moi trng at ......................... 71Bai 24: Chuan b mau at ........................................................................................... 71Bai 25: Xac nh t trong, dung trong va o xop at ................................................. 72Bai 26: Phan tch hat ket at ...................................................................................... 74Bai 27: chua ca t .............................................................................................. 78Bai 28: Phan tch tong so muoi tan, clo ..................................................................... 81


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Bai 29: Phan tch mun trong at ................................................................................. 82Bai 30: Phan tch N tong so trong at ........................................................................ 86Bai 31: Phan tch Si, R2O3 trong at .......................................................................... 89Bai 32: Phan tch Al3+ trao oi trong at ................................................................... 95Bai 33: Xac nh cac dang ton tai cua sat trong at ................................................. 97Bai 34: Xac nh pH at ............................................................................................. 99Bai 35: Phan tch CaO, MgO trong at .................................................................... 102

Chng 7:Phng phap phan tch cac ch tieu moi trng kh ...................... 106Bai 36: Xac nh acid HCl - phng phap hap thu bang nc cat ........................ 106Bai 37: Xac nh CO2 - phng phap hap thu CO2 bang Ba(OH)2 ......................... 107Bai 38: Xac nh sunfur dioxit (SO2) ....................................................................... 109Bai 39: Xac nh Dioxyt nit (NO2) ......................................................................... 111Bai 40: Xac nh Ammoniac .................................................................................... 114Bai 41: Xac nh Hydrosunfua ................................................................................. 116


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CHNG 1: M AUBAI 1: LAY MAU VA BAO QUAN MAU

1.1 Gii thieu chungng vi nhu cau cua xa hoi ngay cang oi hoi chat lng phan tch cang cao va yeucau cua khach hang cung ngay cang a dang, kiem soat va bao am chat lng cuaphep phan tch QAQC (Quanlity Assurance and Quanlity Control) la nham muc ch

tang o tin cay cua khach hang oi vi ket qua cua phep phan tch. Chnh v vayma yeu cau ve chat lng cua phep phan tch at ra hang au.Muc ch cua phep phan tch la tm ra mot cach nh tnh va nh lng thanh phancua cac chat co trong moi trng. Trong phan tch moi trng co mot so muc tieu cuthe:

chun b mt ngn hng d liu nhm xc nh xu hng s bin i mthp cht no trong mi trng

Xc nh chnh xc thnh phn v nng ca mt mu mi trng no nhm a ra gii php cng ngh v x l n

Vi pht trin ny th hng lot cc my mc, thit b phn tch k thut cao ra igp phn tng chnh xc ca mt php phn tch. Tuy nhin sai s ca mt phpphn tch c th n t nhiu ngun: ly mu, vn chuyn v bo qun mu, chn laphng php phn tch, bn thn ngi phn tch, khng hiu chnh thit b hp l, xl v bo co s liu khng chnh xc.

1.2Lay mau, van chuyen va bao quan mauChat lng cua mot phep phan tch phu thuoc rat nhieu vao quy trnh lay mau. Theothong ke co ti 66% sai so cua ket qua phan tch en t viec lay mau sai. o tincay cua mot ket qua phan tch phu thuoc vao chien lc lay mau, ke hoach lay mauva s o lay mau.

Trong phan tch moi trng ngi ta phan biet lam 4 loai mau, ng vi moi loai seco s o lay mau tng ng Loai 1: mau ai dien (Representative) la loai mau mang nhieu tnh chat. e bao

am c tnh ai dien cua mau moi trng ngi ta phai xem xet trang thai tontai cua mau ngoai moi trng o

V du: mau ong the (nc song, ho)Mau d the (chat thai ran)Mau tnh (nc trong ao, ho)Mau ong (nc song, bien)

Loai 2: mau chon la (Selective) hoan toan phu thuoc vao ke hoach lay mau.Chung ta chon la mau sao cho thoa man mot tnh chat thch hp nao o machung ta d nh va bo qua cac chi tiet khac

Loai 3: mau bat ky (Random) khi tnh ai dien khong am bao, lay bat ky nhngphai xem xet cho thoa man mot so tieu ch, nhu cau e ra.

Loai 4: mau hon hp (Composite) hay con goi la mau tron (mixed)


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1.2.1 Thi gian lu mauL khong thi gian cc i t thi im ly mu n lc o mu m mu khng c sbin i ng k no, v mt nguyn tc nn o mu cng nhanh cng tt sau khi lymu. Trong qu trnh vn chuyn v lu mu mi thao tc u phi c ghi nhn.1.2.2 Mot so tnh chat cua mau phan tchKhi xay dng chien lc lay mau phai xem xet en cac yeu to nh: o bay hi, tnh

nhay vi anh sang mat tri, tnh ben vng ve nhiet, tnh phan ng hoa hocMoi nguyen nhan ve s nhiem ban cua mau phai c xem xet can than: s hoa tancua mot so chat, cua vat cha mau vao mau, thanh phan moi trng ben ngoai (bui,hoa chat khac), ac biet chat de bay hiMot vai nguyen nhan gay bien oi mau:- Vi khuan, tao va cacvi sinh vat khac co the tieu thu mot so thanh phan co trong

mau, chung cung co the lam bien oi ban chat cua cac thanh phan va tao ra cacthanh phan mi. Hoat ong sinh hoc nay gay anh hng en ham lng oxi hoatan, cacbondioxit, cac hp chat nit, photpho va oi khi co ca silic.

- Mot so hp chat co the b oxy hoa bi oxy hoa tan trong mau hoac oxy khong

kh (th du nh cac hp chat hu c, sat II, sunfua).- Mot so chat ket tua v du nh CaCO3, Al(OH)3, Mg(PO4)2, hoac bay hi v du

nh oxy, thuy ngan, xianua- pH, o dan ien, ham lng cacbonioxit co the b thay oi do hap thu

cacbonioxit t khong kh.- Cac kim loai hoa tan hoac dang keo, mot so hp chat hu c co the b hap phu

khong thuan nghch len bnh cha hoac len cac hat ran co trong mau- Cac san pham polyme hoa co b depolyme hoa, ngc lai, cac hp chat n gian

co the b polyme hoa.

1.2.3 ieu kien lu tr mau, muc ch phan tchMoi mot mau can phai co che o bao quan thch hp, muc ch la tao ra moi trnglu tr tot lam han che toi thieu phan ng hoa hoc, sinh hoc oi vi mau. Hau hetcac phan ng enzyme xay ra nhiet o 20-30oC (nhiet o phong) nen lu tr mautrong ieu kien lanh va trong khong gian toi. oi khi e lu mau phai them vaonhng chat tr nh chat chong oxy hoa, chong keo tu.1.2.4 Tien x ly mauMuc ch cua phep phan tch la mau ta o phai phu hp vi tnh ai dien cua maumoi trng. Trc khi o thng co mot so cong oan phai thao tac vi mau e phuhp vi thiet b o va phng phap o nh: lac, pha loang, co ac, nghien, cat, loc,

tron1.2.5 La chon phng phap phan tchKhi can nhac la chon phng phap phan tch thng da vao mot so gi y sau ay:Nhng phng phap phan tch ma ta t xay dng nenNhng phng phap c cong bo trong nhng tap ch khoa hoc chuyen nganhNhng phng phap do cac to chc thng mai cung capNhng phng phap c cung cap trong sach chuyen nganh


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Nhng phng phap do cac to chc tieu chuan hoa cong bo (ISO, TCVN)1.2.6 Cac yeu to can can nhac khi la chon phng phap phan tch Gii han phat hien (LOD Limit of detection): la lng nho nhat cua mot

chat can phan tch trong mau moi trng ma phng phap, thiet b nao o cothe phat hien c

o nhay cua phng phap phan tch (Sensitivity): bieu th s thay oi khieu cua phng phap hay cua may khi co s thay oi ve nong o cua chatcan phan tch trong mau. o nhay cua phng phap phan tch chnh la o doccua ng chuan

Hnh 1. 1 Phng trnh ng chuan

o chnh xac cua phng phap phan tch (Accuracy): la o lech gia giatr o c vi gia tr c xac nh thong qua ng chuan. Bieu th sai socua tng phep o trong tng phng phap hay thiet b s dung.

o ung (Precision): la o lech gia gia tr o c vi gia tr thc cua mau o lap lai (Reproducibility): la gia tr tuyet oi cua o lech chuan cua mot

phep o trong cung ieu kien o. Lap lai th nghiem nhieu lan e tin tnghn.

1.2.7 Cac yeu to moi trng phong th nghiem can can nhac- Anh sang mat tri, nhiet o, bui, o rung ong, cac trng ien t-Phng cach thiet ke phong th nghiem: o thong thoang, o am-Phng cach nh v thiet b o: viec bo tr cac thiet b, hoa chat-Phng cach la chon cac dung cu:

oi vi thiet b phai c kiem tra xem van hanh co tot khong, phai hieuchnh thiet b thng xuyen, bao tr, kiem tra tnh sach

oi vi hoa chat phai kiem tra chat lng hoa chat o, ieu kien bao quanhoa chat oi vi cac vat dung khac: kiem tra o sach cac vat dung trc khi o

1.2.8 Phng thc bao quan mauPhng thc bao quan mau nc theo ch tieu phan tch c trnh bay trong bangsau:

a

y=ax+b

a=tga


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Bang 1.1 Phng thc bao quan mau nc

Ch tieu phan tch Phng thc bao quanThi gian tontr toi a

o cng (hardness) Khong can thietCalci (Ca2+) Khong can thiet

Cloride (Cl

-

) Khong can thietFloride (F-) Khong can thieto dan ien 4oC 28 gio acid, o kiem 4oC 24 giMui 4oC 6 giMau 4oC 48 giSulphate 4oC; pH


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1.3.2 Kiem tra tnh thch hp cua phng phap phan tchLap lai th nghiem nham muc ch giup cho ngi phan tch tin tng phng phapang thc hien la ung, ieu nay co ngha la ngi phan tch ang tien hanh ungtrnh t phan tch.Th nghiem thu hoi (Recovery test): khi ban chat cua chat can phan tch trong moitrng ta a xac nh ro ta se lam th nghiem thu hoi bang cach them vao mau o

mot lng xac nh ung chat can thiet o, ta se o mau trc va sau khi them, skhac biet gia hai lan o se cho ta thong tin ve s hien dien cua mau khi so sanhvi ng chuan.o mau khong (blank): la mau khong cha chat can phan tchDung nhng phng phap khac nhau e oThay oi au do Yeu cau ve nang lc: mot so yeu cau chung vi ngi phan tch la tnh can

than, ngan nap, gon gang, ky luat caoTrc khi phan tch: phai hieu ro muc ch cua phng phap o, lch s cua mau,

nh ra ke hoach cho phep oTrong luc phan tch: quan sat can than, ghi nhan cac hien tng xay ra trong quatrnh o, cac s co bat thng xay ra. Kiem tra lai cac ieu kien phong th nghiem,lau chui thiet b, ghi nhan so lieu trong qua trnh o.Sau khi phan tch: quan ly d lieu o c mot cach phu hp, ch ra ngay nhng saiso, mau nen c lu gi mot thi gian cho en khi ket qua c tin tng, sap xeplai khu vc th nghiem e san sang cho phep o tiep theo.

1.4 Cac phng phap ng dung trong phan tch moi trng1.4.1 Phng phap phan tch bang quang hoa

Bc xa ien tLa mot dang nang lng c truyen i trong khong gian vi van toc ln. Hai lythuyet noi len ac tnh cua bc xa ien t:-Bc song: bc xa ien t la mot dang dao ong song hnh sin c ac trng bimot so ai lng v du: nhp o, bc song, tan so song, chu k, bien o dao ong.-Bc thang: xem bc xa ien t la chum cua nhng hat mang nang lng c goila proton E=hxv, moi hat co mang mot nang lng h:hang so Frang, v:tan so daoong song. Nang lng cua proton E t le thuan vi tan so dao ong cua songPhan loai bc xa:Bc xa tia : bc song = 0,005-1,5AO

Bc xa tia X: bc song = 0,1-1005AOBc xa hap thu tia cc tm nam trong vung chan khong: bc song = 10-180nm thuc do s kch hoat nhng electron ngoai cung. ng dung trong phan tch moitrng oi vi mau khBc xa trong vung cc tm: = 180-780nm, anh sang nhn thay c


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Bc xa hong ngoai IR: = 0,78-300m c phat ra do nhng dao ong rung vaquay cua phan t. Phan tch cau truc cua nhng phan t phc tap nhat la nhngphan t hu c.Nhng vung con lai: la vi song, song radioKhi bc xa ien t phat ra truyen qua moi trng vat chat se co mot so hien tngxay ra:

Hien tng hap thu bc xa: mau moi trng se hap thu mot phan nanglng bc xa ien t. Ket qua la nang lng bc xa se b yeu i, lam canc phan tch nh tnh va nh lng mau moi trng.

Hien tng truyen suot: lam mau O e ieu chnh may phan tch Hien tng tan xa: khi bc xa ien t truyen en be mat cua mot vat the

ran, bc xa ien t b oi phng truyen ra nhng hng khac nhau. Hien tng nhieu xa (diffraction): khi cho bc xa ien t qua mot khe

hep, bc xa ien t se c phan tan ra thanh nhieu chum tia khac nhauvi nhng bc song nhat nh ma co pham vi hep hn.

Hien tng khuc xa (refraction): cho bc xa ien t qua hai moi trngkhac nhau, bc xa ien t se b thay oi phng truyen theo mot quy luatnhat nh

Hien tng phan xa: oi phng truyen anh sang Cau tao thiet b quang hoc spectrophotometer

Hnh 1.2 S o cau tao cua Spectrophotometer

1. Nguon phat ra bc xa ien t (Radiation Source): la dung cu phat ra bc xa trongmot vung bc song ma ta mong muon2. Dung cu cha mau (Sample Compartment) hay con goi la Curvet co nhieu hnhdang nh tron, vuong

Hnh 1.3 Cuvet ng mau

3. Thiet b tron va tach song (Wave length selection): co chc nang thu hep bc xaien t, tang cng cng o cua bc xa tai v tr thu hep (khuyech ai bc xa lenv sau khi qua 2 se b yeu i). Trong thc te may quang pho 3 co the la bo loc(fifter) hoac may n sac (monochromater)

1 32 4 5


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Hnh 1.4May n sac Bo loc

4. Detector: ghi nhan tn hieu va chuyen hoa tn hieu nang lng anh sang thanh tnhieu ien (te bao quang ien)

Hnh 1.5 Te bao quang ien

5. Thiet b ieu tuyen tn hieu (Data/Signal pressesing): hien th d lieu di dangso hoa Pho hap thu phan t (Motercular uv-vis)Vung ng dung 180-3000nmMot so khai niem chung lien quan en quang pho hap thu: khi cac phan t cua maumoi trng nhan c mot phan nang lng bc xa no se chuyen len trang thai kchthch va ton tai trang thai nay rat ngan (10-7 10-8s). e giai thch hien tng hapthu nay ngi ta dung mot so khai niem:-o truyen suot (Transmittance) %T = P/PO x 100%-o hap thu (Absorbance) A = -logT = -log P/PO = log PO/P

-o hap thu phan t (Molar Absorptivity) va nh luat BeerA=abcA: o hap thu cua vat chatb: chieu day Curvetc: nong o vat chat trong moi trng nao oa: hang so phu thuoc tnh chat moi trng

A

e


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nh luat Beer ung vi mau loang C#0.01M (do nhng phan t cua moi trngam ac co khoang cach gan nhau, de va cham dan ti khong con c hoi hap thunang lng bc xa)ng dung cu the: chuan o quang hoc, Si quang (gom hai si day truyen bc xaien t)

Hnh 1.6 Mot vai loai may Spectrophotometer1.4.2 Phng phap phan tch sac ky

ai cng ve phng phap sac ky

ac iem cua phng phap sac ky

Phng phap sac ky do nha bac hoc ngi Nga Mikhail Tswett (1872-1919)

phat minh vao nam 1903. Ong a dung cot cha oxit nhom tach cac pigment cua la

cay xanh thanh cac vung mau rieng biet va ong a at ten cho phng phap nay la

sac ky (chromatography)

Hnh 1.7 Th nghiem cua nha bac hoc Mikhail Tswett


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Sac ky la mot phng phap dung e phan tach nhng thanh phan gan giong nhautrong mot mau moi trng phc hp. Trong ky thuat sac ky, mau c hoa tan vaotrong pha ong (mobile sample) co the la mot dong kh, chat long hay la mot dongchat long sieu ti han (nhiet o, ap suat co nh). Pha ong nay c ay qua motpha tnh ma khong tron lan pha ong. Pha tnh co the co nh tren mot cot hoac trenbe mat cua chat ran. Thanh phan cua hai pha c chon la sao cho cac thanh phan

khac nhau cua mau moi trng se phan bo lan nhau gia pha ong va pha tnh. Cacthanh phan c lu gi manh hn bi pha tnh se chuyen ong mot cach chamchap hn so vi dong pha ong, va ngc lai nhng thanh phan c lu gi bi phatnh yeu hn se chuyen ong nhanh hn. Ket qua la nhng thanh phan khac nhau sec tach ri ra.

Bang 1.2 Phan loai cac dang sac kyLoai Phng phap Pha tnh Trang thai can

bang

Sac ky long(pha ong lachat long)

-Sac ky long-long(sac ky phan bo) -Nhng chat longc hap thu trenbe mat chat ran

-S phan bo giacac chat long khongtron lan nhau

-Sac ky long-lienket pha

-Nhng phan thu c lien ket trenbe mat chat ran

-S phan bo giachat long va be matlien ket pha o

-Sac ky long-ran(sac ky hap thu)

-Nhng hat nhoihoac chat ran

-Hap phu

-Sac ky trao oiion

-nha trao oi ion

-Sac ky ngoai c -nhng hat nhoi cokhoet lo

Sac ky kh(pha ong lachat kh)

-Sac ky kh-long -Nhng chat longc hap thu trenbe mat chat ran

-S phan bo giakh va long

-Sac ky lien ketpha

-Nhng phan thu c nh tren bemat chat ran

-S phan bo giakh va be mat lienket pha o

-Sac ky kh-ran -Chat ran -Hap phu vat ly nthuan

Sac ky dongti han

-Nhng phan thu c nh tren bemat chat ran

-S phan bo giadong ti han va bemat lien ket pha


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Hnh 1.8 Mo hnh may sac ky longCac ai lng c ban trong sac ky

Mot qua trnh sac ky c ac trng bi rat nhieu cac ai lng ac trng thuyong hoc cua cot sac ky, cac ai lng ac trng cho s lu gi, ai lng ac trngcho s phan tach va mot so ai lng khac. Trong phan nay chung toi ch e cap timot so ai lng ac trng quan trong cua mot qua trnh sac ky.

Hnh 1.9 Sac ky o

Trong o:- tR1, tR2: Thi gian lu cua cau t th nhat va th 2

- tM: Thi gian lu chet

- w1, w2: Be rong ay cua mui sac ky


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1.4.3 Phng phap phan tch khoi lngPhng phap phan tch khoi lng la mot phng phap cua phan tch nh lng datren s o chnh xac khoi lng cua chat can xac nh, hoac cua thanh phan noc tach ra trang thai tinh khiet hoa hoc, hoac di hp chat thch hp (thngcac thanh phan nay khong oi va biet chnh xac).Trong phng phap nay ngi ta thng can mot lng mau chnh xac (c goi la

lng can) can phan tch, roi hoa tan no thanh dung dch. Neu oi tng la dungdch th lay mot the tch chnh xac cua no. Sau o ket tua hp phan can xac nhdi dang mot hp chat rat t tan, oi khi di dang n chat. Loc ra, say va nunge chuyen thanh mot hp chat ben co thanh phan hoa hoc xac nh (tc la co congthc hoa hoc mot dang nhat nh) c goi la dang can. Cuoi cung em can kettua a c say hoac nung o tran can phan tch, da vao khoi lng cua no e tnhham lng chat can xac nh.V du:-e xac nh ham lng cua sat co trong mau quang, ngi ta can chnh xac mot

lng mau quang va chuyen hoan toan sat ve dang Fe

3+

, ket tua Fe

3+

di dangFe(OH)3.xH2O. Loc, ra va nung ket nay en khoi lng khong oi e chuyen kettua hoan toan ve dang Fe2O3. Cuoi cung can lng ket tua sau khi nung nay va tnhra ham lng cua sat.-Xac nh o am cua mau at, xac nh chat ran l lng trong mau nc...

1.4.4 Phng phap chuan o the tchPhng phap nay thng dung e xac nh nong o cua mot chat bang cach dungmot chat khac a biet nong o ket hp vi ch th thch hp da tren lng the tchdung dch phan ng tai iem oi mau cua ch th.

Ap dung nh luat bao toan ng lng: Cac chat phan ng vi nhau theo caclng ty le vi ng lng cua moi chat trong phan ng o.

CN1 x V1 = CN2 x V2

Trong o: CN la nong o ng lngV la the tch dung dch

Tuy thuoc vao loai phan ng dung lam c s cho moi phng phap ma phng phapthe tch c at ten theo o. Cac phng phap phan tch the tch chia lam 4 loaida vao phan ng ma chung dung e xac nh iem tng ng :Phng phap ket tua: co phan ng tao thanh hp chat t tan ( ket tua).Phng phap trung hoa : co phan ng acid - bazPhng phap oxy hoa kh: co phan ng gia cac chat kh va chat oxy hoa .Phng phap Complecxon: co phan ng tao phc gia ion kim loai vi complexon.


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BAI 2: DUNG DCH CHUAN1. ai Cng

Trong qua trnh phan tch nc va nc thai thng gap nhieu dung dchchuan ma nong o ghi di hnh thc so hu t thay v so thap phan hay so nguyen.S viec tren c giai thch bi hai ly do:

Ket qua bao cao: Cac so lieu c yeu cau ghi the nao e ngi thiet ke(thng la nhng ngi khong chuyen mon trong nganh hoa) de hnh dung. Do on v thng s dung la mg/l, n v nay c dung pho cap.

Tnh toan: oi vi ngi lam cong tac xet nghiem, cong thc cang de dang,de nh cang giam thi gian tnh toan, cang tranh c nhng nham lan co the xayra.T hai ly do tren, viec chon nong o dung dch chuan c tien hanh nh mot thongle sao cho: 1 lt dung dch nh phan luon luon tng ng vi 1g chat can nhlng. ieu nay cung co ngha 1ml dung dch chuan se tng ng vi 1mg chat cannh lng. Ro rang viec pha che dung dch chuan khong phu thuoc vao ban chat

chuan ma tuy thuoc vao khoi lng ng lng (KLL) chat can chuan.Th du phan ng

KLLChat can chuan

Dung dchchuan

Nong o dungdch chuan

nh lngamonias

KLLNH3 = 17 Acid N/17

nh lngnitrogen dangamonia

KLLN-NH3 = 14 Acid N/14

nh lng okiem dang CaCO3

KLLCaCO3 = 50 Acid N/50

nh lng carbondioxide

KLLCO2 = 44 Kiem N/44

nh lng oacid dang CaCO3

KLLCaCO3 = 50 Kiem N/50

nh lng clorua KLLCl = 35,45 AgNO3 N/35,45nh lng NaCl KLLNaCl = 58,4 AgNO3 N/58,44nh lng oxyhoa

KLLO2 = 8 Kh N/8

Sau cung cong thc tnh toan ham lng chat can nh lng trong 1 lt mau cungtr nen n gian va de nh

Nong o/ham lng chat khao sat (mg/l) =mlmau

chuanmldungdich (1)

Mot vai trng hp nh nh phan oxi hoa tan vi the tch mau an nh trc, nongo dung dch chuan se c hieu chnh vi muc ch toi gian viec tnh toan. Luc o1ml dung dch chuan khi dung se tng ng vi 1mg/l oxy.


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2. Chuan b dung dch chuanKhong phai xac nh lai nong o dung dch chuan sau khi pha che, hoa chat

chuan phai co o tinh khiet cao va viec can cac loai hoa chat can can than, ungtheo khoi lng tnh toan. Sau khi rot vao cac bnh nh mc co the tch rieng biet,viec ong o pha che oi hoi mc o chnh xac cao. Thc te nhieu trng hpkhong co so lieu ve o tinh khiet hoac kho o lng chnh xac v hoa chat de bay

hi, hut am, bien chat nhanh trong khong kh. Dung dch sau khi pha xong phai nhlng lai vi mot dung dch chuan c s ma nong o a biet ro va am bao.

3. nh chuan mot dung dch vi mot dung dch chuan c s3.1 Pha che va xac nh lai nong o dung dch NaOH N/50

Dung dch NaOH thng c s dung trong phep nh phan o acid didang CaCO3 co phan t lng M=100, ng lng gam = 50. Do o nong o yeucau la N/50. Tuy nhien NaOH thng mai thng dang vien kho can chnh xac,o hut am cao, de bien chat do CO2 trong khong kh. V the dung dch NaOH N/50

thng c pha loang t dung dch chuan co nong o NaOH 1N e co o chnh xaccao.Dung dch c s la H2SO4 N/103.1.1. Thiet b va dung cu

Can ky thuat sai so 0.01gBecher 500mlBnh nh mc 1000 mlBuretErlen 125ml

3.1.2. Hoa chat

NaOH tinh khiet dang vienDung dch chuan c s H2SO4 N/103.1.3. Thc hanha.Tnh s khi

NaOH tinh khiet co phan t gam M=40 trung hoa 1,008g H+ , so ng lnggam =1e pha che 01 lt dung dch NaOH 1N, khoi lng NaOH tnh c laM/1=40/1=40ge loai bo cac yeu to co the lam giam nong o thc te, he so an toan c tang 5%Khoi lng NaOH can thiet : 401,05 =42gb. Cach lam

Dung becher can 42g NaOH vien bang can ky thuatHoa tan lng NaOH trong 500ml nc cat, rot vao bnh nh mc 1000ml.

Tran sach becher nhieu lan vi nc cat. Nhap chung nc ra vao bnh nh mc.Them nc cat cho u 1000ml


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Dung pipet hut 5ml dung dch tren ra erlen nh phan bang dung dch chuanH2SO4 N/10. Ch th mau phenolphathalein oi t hong nhat sang mat mau. Nong oNaOH pha che theo cong thc:

N1V1=N2V2 (2)Trong o

N1: Nong o dung dch acid chuan c s N/10

V1: The tch dung dch H2SO4 N/10 a dung (ml)N2: Nong o dung dch NaOH pha cheV2: The tch dung dch NaOH trch ra e nh phan (ml)Ket qua tnh c thng ln hn nong o mong muon. Ap dung cong thc (2)

tnh lng nc can e pha loang dung dch NaOH tren thanh 1000ml dung dchNaOH 1NT dung dch NaOH 1N va co, pha che 1000ml dung dch NaOH N/503.2. Pha che va xac nh lai nong o dung dch H 2SO4 N/50

Dung dch acid sulfuric thng c s dung trong phng phap nh phan o

kiem di dang CaCO3, do o nong o yeu cau la N/50. ac tnh cua acid sulfuricam ac la de hut am, kho o lng va de gay phong, do o dung dch H 2SO4 N/50thng c pha loang t dung dch H2SO4 1N lu tr. Dung dch chuan la NaOH1N va NaOH n/50 a pha loang trong phan tren.3.2.1. Thiet b va dung cu

Xem lai phan 23.2.2. Hoa chat

Acid sulfuric P-A, o tinh khiet 96-98%. Khoi lng rieng d=1.84-1.86g/cm3.Dung dch NaOH 1N

3.2.3. Thc hanh

a. Tnh s khiAp dung cong thc tnh gan ung :V=100M N/b p dTrong o:V: The tch acid sulfuric am ac tnh toan (ml)M: Phan t gam acid sulfuric (g)N: Nong o muon phab: Tr so ng lngp: o tinh khiet (%)d: Khoi lng rieng (g/cm3)Tng t nh tren he so an toan c tang them 2%.The tch acid sulfuric am ac can thiet: V(ml)=v1,02

b. Cach lamDung pipet va qua bop cao su hut can than V(ml) acid sulfuric am ac va

500ml nc cat nh san trong bnh nh mc 1000ml.Dung bnh xt ra sach acid sulfuric con ong trong pipet, rot tat ca nc ra

nhap chungThem nc cat cho u 1000ml


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Dung pipet trch dung dch tren ra erlen. nh phan bang dung dch NaOH 1Na pha che trong giai oan tren. Ch th mau phenolphthalein chuyen t khong mausang mau hong nhat ben. Nong o dung dch H2SO4 c tnh t cong thc (2).

Pha loang dung dch tren thanh 1000ml H2SO4Vi dung dch H2SO4 1N va co, pha che 1000ml H2SO4 N/503.3. Dung dch chuan Fe

3.3.1. Dung dch lu tr sato 20ml H2SO4 am ac vao 50ml nc cat va them vao 1,404

Fe(NH4)2(SO4)2.6H2O. Pha thanh 1000ml vi nc cat (1,00ml = 200g Fe).3.3.2. Dung dch chuan : chuan b moi khi s dung.

Lay 50ml dung dch lu tr sat cho vao bnh nh mc 1000ml, them nc catti vach nh mc (1,00ml = 10,00g Fe).3.4. Dung dch chuan N-NO3 : (1ml = 2 g N-NO3)3.4.1. Dung dch N-NO3 lu tr: (1ml = 2 g N-NO3)Hoa tan 0,7218g Anhydrous Potassium Nitrate KNO3 + nc cat = 1 lt.

3.4.2. Dung dch N-NO3 chuan: (1ml = 0,002mg = 2 g N-NO3).Pha loang 10ml dung dch lu tr thanh 500ml e co 1ml dung dch chuan =2 g N-NO3.3.5. Dung dch chuan N-NH3(1ml= 10 g N-NH3)3.5.1. Dung dch lu tr NH3 : ( 1ml=1mg N= 1000 g N-NH3)Hoa tan 3,819g NH4Cl( a say kho 100oC), them nc cat cho u mot lt (1ml=1mgN= 1,22 mg NH3)3.5.2. Dung dch chuan N-NH3: (1ml = 10 g N-NH3)Pha loang 10ml dung dch lu tr vi nc cat cho u mot lt (1ml=0,010 mgN

=0.0122mg NH3)3.6. Dung dch photphate chuan3.6.1. Dung dch lu tr

Hoa tan 219,5 mg KH2PO4 khan (say kho 105o C mot gi) trong nc catva nh mc thanh 1000 ml (1,00 ml=50,0 g P-PO4)3.6.2. Dung dch chuan

Dung 50 ml dung dch chuan pha loang thanh 1000 ml. Dung dch nay conong o 1,00 ml =2,5 g p-PO4.3.7. Dung dch sulfate chuan: (1,00 ml= 100 g SO42-)

Lay chnh xac 10,4 ml H2SO4 0.0200N chuan + nc cat = 100ml hoac147,9mg NaSO4 khan +nc cat pha thanh 1000 ml.


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4. Cong thc tnh pha dung dch theo cac nong o4.1 oi vi chat ran

- Pha theo nong o mol CM (mol/lit):

mct =P

VMC PhaAM 100

1000

...

Trong o:mct khoi lng mau can can pha, gCM nong o hoa chat can pha, mol/lt.MA phan t lng cua chat can pha,VPha the tch mau can pha, ml.P la o tinh khiet cua hoa chat.

- Pha theo nong o ng lng CN (N):

mct =P

VC PhaN 1001000

..

Trong o:mct khoi lng mau can can pha, gCN nong o ng lng hoa chat can pha, N so ng lng cua hoa chat can pha.VPha the tch mau can pha, ml.P la o tinh khiet cua hoa chat.

- Pha theo nong o ppm:

mct =PM

MVC

nhdangxac

dangcanphappm 100

10

*3

Trong o:Cppm la so mg chat tan trong mot ltmct khoi lng mau can can pha, g.VPha the tch mau can pha, lt.P la o tinh khiet cua hoa chat.%.Mdang can: phan t lng cua dang can.Mdang xac nh : phan t lng cua dang can xac nh

- Pha nong o %:

mct = PdVC pha 100

.100

(%).

Trong o:

C% nong o phan tram cua dung dch can pha.d la t trong cua dung dch, vi dung dch loang xem d 1Vpha the tch dung dch can pha, ml.P o tinh khiet cua hoa chat.


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4.2 oi vi chat long- Pha theo nong o mol CM (mol/lit)

V =dP

VMC PhaM

.10.

..

Trong o:V the tch hoa chat am ac can hut e pha (ml)CM nong o hoa chat can pha (mol/lt)VPha the tch mau can pha (ml)P o tinh khiet cua hoa chat can pha, (vd p = 99)d la khoi lng rieng cua dung dch can pha (g/ml)

- Pha theo nong o ng lng CN (N)

V =dP

VC PhaN

.10.

..

Trong o:V the tch hoa chat am ac can hut e pha, ml.CN nong o ng lng hoa chat can pha, N.VPha the tch mau can pha, ml.P o tinh khiet cua hoa chat can phad la khoi lng rieng cua dung dch can pha. = M/z

Hay CM = CN/z- Pha theo nong o %

V = phaV

dCdC

11

22

Trong o:C1 : nong o phan tram cua dung dch co nong o cao ban au (P)C2 : nong o phan tram cua dung dch can pha.V: the tch dung dch co nong o cao ban au ml.Vpha the tch dung dch can pha, ml.Vi cac dung dch co nong o xap x nhau, co the xem d1 d2


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CHNG 2PHAN TCH CAC THONG SO VAT LY

BAI 3: pH, EC, O MAN

1. Y ngha moi trng o pHpH la mot thuat ng ch o acid hay baz cua mot dung dch, pH anh hng en cacqua trnh sinh hoc trong nc va co anh hng en s an mon, hoa tan cac vat lieu.Trong ky thuat moi trng, pH c quan tam trong cac lnh vc nh qua trnh keotu, qua trnh lam mem nc, qua trnh kh trung, on nh nc

Trong x ly nc thai bang phng phap sinh hoc, ch tieu pH c duy tr tronggii han toi u e sinh vat phat trien, thng 6.5-7.5

H2O H+ + OH-

pH = -lg[H+

]pH + pOH = 14

2. Thc hanhTrong phan nay sinh vien se thc tap s dung may o pH- Lac eu mau trc khi o ra coc 100ml e o- Ra sach ien cc bang bnh tia- Bat may, nhung ien cc vao mau can o- i cho gia tr pH tren may on nh oc ket qua- Ra sach ien cc bang nc cat, ngam ien cc vao dd bao quan ien cc.

3. EC, o manGiao vien hng dan sinh vien s dung may o

4. Cau hoin v o EC va o man la g?


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BAI 4: CHAT RAN

1. Gii thieu chung1.1. Y ngha moi trngChat ran trong nc bao gom chat ran ton tai dang l lng va dang hoa tan. Trongnc co ham lng chat ran cao gay cam quan khong tot va cac benh ng ruot

cho con ngi.1.2 Cac nh nghaChat ran tong cong (TS) = Chat ran l lng (SS) + Chat ran hoa tan (TDS)Chat ran on nh (thanh phan la cac chat vo c): la phan con lai cua chat ran tongcong sau khi ot 550OCChat ran khong on nh hay con goi la chat ran bay hi (VS - thanh phan la cac chathu c): la lng chat ran tong cong mat i sau khi ot 550OC

2. Thc hanh

2.1 Xac nh chat ran tong cong (Total Soilds)- Chuan b coc s a say kho 100oC trong 1h, ngui trong bnh hut m n nhit phong, can coc xac nh khoi lng coc ban au mo (mg)- Chon the tch mau sao cho lng can nam trong khoang 2,5-200mg, lac eu mautrc khi s dung- Cho mau vao coc say 100oC e lam bay hi nc- e nguoi trong bnh hut am en nhiet o phong- Can xac nh khoi lng m1 (mg)

Chat ran tong cong(mg/l) = (m1 mo)x1000/Vmau(ml)

2.2 Xac nh chat ran bay hi (VS Volatile Solids)- Tiep tuc ly coc tren em nung 550OC- e nguoi trong bnh hut am en nhiet o phong- Can xac nh khoi lng m2 (mg)

Chat ran bay hi (mg/l) = (m1 m2)x1000/Vmau(ml)

2.3 Xac nh chat ran l lng (Suspended Soilds) bang phng phap khoi lng- Chuan b giay loc si thuy tinh a say kho 100oC trong 1h, can giay loc xac nhkhoi lng ban au m3 (mg)

- Loc mot the tch mau phu hp qua giay loc (mau a tron eu trc khi loc)- Say giay loc 100oC e lam bay hi nc- e nguoi trong bnh hut am en nhiet o phong- Can xac nh khoi lng m4 (mg)

Chat ran l lng (mg/l) = (m4 m3)x1000/Vmau(ml)2.4 Xac nh chat ran l lng (SS) bang phng phap o quangLac eu mau trong bnh, lay 50ml mau vao coc 100mlBat may, vao ma chng trnh 630-Enter


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Chnh bc song ve 810nmCho nc cat vao Curet en vach trang, t vo bung o, y np, nhan Zero choman hnh xuat hien 0.SUSP.SOLIDSCho mau vao Curvet, bam read oc gia tr o.

2.5 Xac nh chat ran hoa tan (TDS)Giao vien hng dan sinh vien s dung may o

2.6 Mt s ch s khacSVI: ch s lng ca bun

=SS

VSVI

1000

Trong o:SS: cht rn llng (mg/l)

V: th tch lp bun lng sau 30 phut trong ng Imhoff1000ml (l)SVI < 100: bun lng ttSVI >100: bun ni b mt nhiu100< SVI < 200: bun ni t3. Cau hoi1.Giai thch tam quan trong cua viec phan tch chat ran trong cac lnh vc:a. Ham lng chat ran hoa tan va viec cap nc o th.b. Chat ran tong cong va chat ran bay hi oi vi nc thai va bun lang.c. Chat lang c va nc thai sinh hoat.2. D oan ket qua phan tch va gia tr thc khi xac nh ham lng chat ran trongcac ieu kien sau:a. Coc nung con am.b. Xac nh tong chat ran bay hi khi t le magan carbonate cha trong mau cao.


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BAI 5:O UC

1. Gii thieu chung1.1. Y ngha moi trngo uc cua nc bat nguon t s hien hu cua vo so vat the li ti trang thai huyenphu nh at set, vat chat hu c va vo c, vi sinh vat gom cac loai phieu sinh ong

vat.1.2. Nguyen tacNguyen tac c ban cua phng phap nay da tren s hap thu anh sang cua cac canl lng co trong dung dch.1.3. Cac tr ngaiCan ln co kha nang lang nhanh, curvet ban, co bot kh trong mau, o mau that cuamau la nhng nguyen nhan anh hng ti ket qua o uc.

A) XAC NH O UC BANG PHNG PHAP DNG NG CHUAN

2. Dung cu, thiet b va hoa chat2.1. Dung cu va thiet b :May Spectrophotometer.Pipet 5ml, 25ml.2.2. Hoa chat :Dung dch lu tr4000FTU (s dung trong mot thang)

+ Dung dch 1: hoa tan 1g hydrazine sulfate (NH2.H2SO4) trong 100ml nccat.

+Dung dch 2: hoa tan 10g hexamethylenetetramine (C6H12N4) trong 100mlnc cat.

+ Hoa 5,0ml dung dch 1 va 5,0 ml dung dch 2. Pha loang thanh 100ml vinc cat, sau o e yen 24 gi nhiet o 253oC. Dung dch nay co o uc la 4000FTU. Lac eu khi s dung.

- Nc dung pha loang khong mauDung dch chun 400 NTU: Ly 100 ml dung dch lu tr c 4000 NTU phalong vi nc ct, nh mc thnh 1000 ml.3. Thc hanh3.1. Lap ng chuanPha che dung dch chuan: pha loang t dung dch chuan e co o uc chuan theobang sau :STT 0 1 2 3 4 5 6Vdung dch chuan (ml)400FTU

0 2 4 6 8 10 12

Vnc cat (ml) 100 98 96 94 92 90 88o uc (FTU) 0 8 16 24 32 40 48

o o hap thu cua cac dung dch chuan tren may spectrophotometer bc song450nm.


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4. Cach tnhT o mau va o hap thu cua dung dch chuan, ve gian o A = f(C), s dung phngphap bnh phng cc tieu e lap phng trnh y = ax + b. T gia tr o hap thu A mcua mau, tnh nong o Cm. Neu tr so Am cua mau vt qua cac tr so cua dung dchchuan, phai pha loang mau en nong o thch hp.

B) XAC NH O UC BANG CHNG TRNH CAI SAN TREN MAYS dung may spectrophotometer HACH-DR 2010Lac eu mau trong bnh, lay 50ml mau vao coc 100mlBat may, vao ma chng trnh 750-EnterChnh bc song ve 860nmCho nc cat vao Curet en vach trang, nhan Zero cho man hnh xuat hien0.FAUTURBIDITYCho mau vao Curvet, bam read oc gia tr o.5. Cau hoi

1. Nguyen nhan tao o uc cho:Dong song, dong song b o nhiem, nc thai sinh hoat?2. Co s lien quan nao gia cac n v o o uc: mgSiO2/l, FTU, NTU?

BAI 6: O MAU

1. Gii thieu chung1.1. Y ngha moi trngMau cua nc thien nhien do mun, phieu sinh vat, cac san pham t s phan huychat hu c tao ra. Tuy nhien mot so ion kim loai hay nc thai cong nghiep cung

la nguyen nhan gay cho nc co mau. Theo thoi quen chung ta ngh mau cua ncla mau quan sat c ngay sau khi lay mau. Thc ra ay ch la mau bieu kien gommot phan t chat cac chat hoa tan va phan con lai do chat huyen phu tao thanh. Vvay mau bieu kien c xac nh ngay tren mau nguyen thuy ma khong can loai bochat l lng. Ngoai ra con co o mau thc cua mau. o mau thc c xac nhtren mau a qua ly tam e loai bo cac hat l lng. Khong nen loc e loai bo cac hatl lng trong nc v cac cau t mau co the b hap phu tren giay loc.1.2. Nguyen tacNguyen tac c ban cua phng phap nay da tren s hap thu anh sang cua cac hpchat mau co trong dung dch.1.3. Cac tr ngaio uc anh hng en o mau thc cua mau. Ngoai ra o mau con tuy thuoc vaopH cua nc, do o trong bang ket qua cn ghi ro pH luc xac nh o mau.


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A) XAC NH O MAU BANG PHNG PHAP DNG NG CHUAN2. Dung cu, thiet b va hoa chat2.1. Dung cu va thiet bMay Spectrophotometer.Pipet 10ml, 50ml.2.2. Hoa chatDung dch mau chuan potassium chloroplatinate K2PtCl6 (tng ng vi 500 n vmau Pt-Co). Hoa tan 1,246g K2PtCl6 va 1g CoCl2.6H20 trong nc cat + 100ml HClam ac, nh mc en 1000ml bang nc cat.

3. Thc hanh3.1. Lap ng chuan:1ml dung dch chuan = 500 Pt-CoSTT 0 1 2 3 4 5Vdung dch mau chuan (ml) 0 5 10 15 20 25

Vnc cat (ml) 50 45 40 35 30 25o mau Pt-Co 0 50 100 150 200 250o o hap thu cua cac dung dch chuan bc song 455nm.

B) XAC NH O MAU BANG CHNG TRNH CAI SAN TREN MAYS dung may spectrophotometer HACH-DR 2010Bat may, vao ma chng trnh 120-EnterChnh bc song ve 455nmCho nc cat vao Curet en vach trang, nhan Zero cho man hnh xuat hien 0.UnitsPtCo APHACho mau vao Curvet, bam read oc gia tr o.4. Cau hoi- Nguyen nhan gay ra o mau?- The nao la o mau bieu kien, o mau thc?


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CHNG 3PHAN TCH CAC THONG SO THE TCH

BAI 7: CHLORIDE

1. Gii thieu chung1.1. Y ngha moi trngChloride (CT) la ion chnh trong nc thien nhien va nc thai. V man cua chloridethay oi tuy theo ham lng va thanh phan hoa hoc cua nc. Vi mau cha 250mg Cl-/l ngi ta a co the nhan ra v man neu trong nc co cha ion Na+. Tuynhien, khi mau nc co o cng cao, v man lai kho nhan biet du nc co cha en1000 mg Cl-/l. Ham lng chloride cao se gay an mon cac ket cau ong kim loai. Vemat nong nghiep, chloride gay anh hng xau en s tang trng cua cay trong.

1.2. Nguyen tac

Trong moi trng trung hoa hay kiem nhe, potassium chromate (K 2CrO4) co thec dung lam chat ch th mau tai iem ket thuc trong phng phap nh phanchloride bang dung dch silver nitrate (AgNO3).Ag+ + Cl- AgCl (Ksp = 3 10-10) (1)2Ag+ + CrO42- Ag2CrO4 (Ksp = 5 10-12) (2)

o nauDa vao s khac biet cua tch so tan, khi them dung dch AgNO 3 vao mau co honhp Cl- va CrO42-, Ag+ lap tc phan ng vi ion Cl- di dang ket tua trang en khihoan toan, sau o phan ng (2) se xay ra cho ket tua o gach de nhan thay.

1.3. Cac tr ngaiNhng chat thng co trong nc uong hau nh khong anh hng g en viec nhphan. Cac ion bromide, iodide, cyanide c xem nh tng ng vi chloride.Rieng sulfide, thiosulfate, sulfit co the can thiep vao phan ng (1). Tuy nhien sulfitde dang b oxy hoa bi nc oxy gia (H2O2) trong moi trng trung hoa. Thiosulfateva sulfide b mat anh hng trong moi trng kiem. Orthophosphat vi ham lngcao > 25 mg/l cung tac dung vi silver nitrate nhng ieu nay t xay ra. Ham lngsat tren 10 mg/l se che lap s oi mau tai iem ket thuc.2. Dung cu, thiet b va hoa chat

2.1. Dung cu va thiet b- 02 Becher 100 ml- 03 Erlen 100ml- 02 Pipet 10ml- 01 Buret 10ml2.2. Hoa chat

Dung dch AgNO3 0,0141N: can 2,395g AgNO3 hoa tan vi nc cat va nhmc thanh 1 lt.


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Ch th mau K2CrO4: hoa tan 2,5 g K2CrO4 trong 30 ml nc cat, them tnggiot AgNO3 en khi xuat hien mau o ro. e yen 12 gi, loc, pha loang dung dchqua loc thanh 50 ml vi nc cat.

Dung dch huyen treo Al(OH)3: hoa tan 125 g KAl(SO4).12H2O hayAl(NH4)(SO4)2.12H2O trong 1 lt nc cat, lam am 600C, them t t 55 ml NH4OHam ac, lac eu. i 1 gi ra huyen troc nhieu lan vi nc cat en khi nc ra

khong con Cl- na (th bang AgNO3) sau o them nc cat cho u 1 lt.Ch th mau phenolphthalein.Dung dch NaOH 0,1 N(hoac H2SO4 0,1N) tuy pH mau ban au.Nc oxy gia H2O2 30%.

3. Thc hanhLay 50 ml mau cho vao Erlen, dung NaOH loang hoac H2SO4 loang e chnh

pH.nh phan mau trong khoang pH = 7 10 (tot nhat la 7 - 8). Neu pH ngoai

khoang nay, tot nhat nen trung hoa trc khi them 3 giot ch th K2CrO4.Dung dung dch AgNO3 0.0141N nh phan en khi dung dch t mau vangchuyen sang mau o gach (co the so vi mau trang gom nc cat + ch th K2CrO4).Ghi nhan the tch V1 ml AgNO3 s dung.

Lam mau trang co the tch ong vi the tch mau. Ghi nhan the tch Vo mlAgNO3 s dung.Lu y:

Nu mu co nng Cl- cao th phai tien hanh pha loang mauNeu mau co o mau cao, them 3 ml huyen treo khuay ky, lang, loc, ra giay

loc, nc ra nhap chung vao nc qua loc.

Neu co sulfide, sulfit hoac thiosulfate, them tng giot NaOH 0,1N cho en khioi mau phenolphthalein. Them H2O2 quay eu, sau cung trung hoa vi H2SO40,1N.

4. Cach tnh(V1 - Vo) 500

Chloride (mg/l) = -----------------------ml mau

NaCl (mg/l) = Chloride (mg/l) 1,65Trong o :

V1 : The tch dd AgNO3 dung nh phan mau thatVo : The tch dd AgNO3 dung nh phan mau trang

5. Cau hoi1. Tai sao phai thc hien mau trang trong phng phap nh phan chloride?2. nh phan chloride bang phng phap Morh c thc hien trong moi trng

trung hoa. Giai thch tai sao?3. Ket qua nh phan chloride se nh the nao khi them mot lng tha chromate?


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BAI 8: O ACID

1. Gii thieu chung1.1. Y ngha moi trngo acid bieu th kha nang phong thch proton H+ cua nc. o acid cua mau nc

phan ln do s hien dien cua cac loai acid yeu nh acid carbonic, acid tanic, acid

humic bat nguon t phan ng phan huy chat hu c gay ra, phan khac do s thuyphan cac muoi cua acid manh nh sulfate nhom, sat tao thanh. ac biet khi b cacacid vo c tham nhap, nc se co pH rat thap.

Nc thien nhien s dung cho cap nc luon duy tr mot the can bang gia cac ionbicarbonate, carbonate va kh carbon dioxide hoa tan, do o nc thien nhienthng ong thi mang hai tnh chat oi nhau: tnh acid va tnh kiem. Khi b onhiem bi cac acid vo c hoac cac muoi acid t khu vc ham mo, at phen hoac donguon nc thai cong nghiep, pH thap hn 7 kha nhieu.

Trong thc nghiem hai khoang pH chan c s dung e bieu th s khac biet tren.Khoang pH th nhat ng vi iem oi mau cua chat ch th methyl cam (t 4,2 4,5) anh dau s chuyen bien anh hng cua cac acid vo c manh sang vung anhhng cua carbonic acid. Khoang pH th hai ng vi iem oi mau cua chat ch thphenolphtalein (t 8,2 8,4) chuyen sang vung anh hng cua nhom carbonatetrong dung dch.

1.2. Nguyen tac chnhDung cac dung dch kiem manh e nh phan o acid cua ca acid vo c manh cung

nh acid hu c hoac acid yeu.o acid do anh hng cua acid vo c c xac nh bang cach nh phan en iemoi mau cua ch th methyl cam nen c goi la O ACID METHYL (dung dch tmau o chuyen sang da cam).Qua trnh tiep tuc nh phan sau o e xac nh o acid toan phan c thc hienen iem oi mau cua ch th phenolphthalein, goi la O ACID TONG CONG(dung dch khong mau chuyen sang tm nhat).

1.3. Cac tr ngaiCac chat kh hoa tan lam anh hng en o acid la CO2, H2S, NH3 co the b mat ihoac hoa tan vao mau trong qua trnh lu tr hoac nh phan mau. Co the giam anhhng nay bang cach nh phan nhanh chong, tranh lac manh va tranh e mau nico nhiet o cao hn nhiet o ban au cua mau.Khi nh phan mau nc cap, ket qua thng b anh hng bi ham lng chlorinekh trung nc co tnh tay mau. Muon tranh sai so nay, can them vai giot Na2S2O30,1N vao mau e loai bo anh hng cua chlorine. Neu mau co o mau va o uccao, phai xac nh o acid bang phng phap chuan o ien the.


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2. Dung cu- thiet b hoa chat2.1. Dung cu02 Erlen 150 ml01 Ong ong 100 ml01 Buret 25 hoac 50 ml2.2. Hoa chat

Dung dch sodium hydroxide (NaOH) 0,02N: pha dung dch NaOH 1N(can40g NaOH vien + nc cat = 1 lt) lay 20 ml dung dch NaOH 1N + nc cat = 1 lt.nh phan lai bang dung dch potassium biphthlate 0,02N (hoa tan 4,085gKHC8H4O4 a say kho trong 2 gi 1200C va lam nguoi trong bnh hut am + nccat = 1 lt)

Ch th phenolphthalein: 500 mg phenolphthalein + 50 ml methanol + nccat = 100 ml

Ch th methyl cam : 50 mg methyl cam + nc cat = 100 ml

3. Thc hanhNeu mau la nc uong, trc khi nh phan them mot giot Na2S2O3 0,1 N eloai anh hng cua chlorine.

Dung pH ke o pH cua mau. Neu mau co gia tr pH < 4,5: lay 10 ml mau vaoerlen, them 3 giot methyl cam. Dung dung dch NaOH 0,02 N nh phan en khidung dch co mau da cam. Ghi nhan the tch V1 ml dung dch NaOH a dung e tnho acid methyl.

Neu mau co gia tr pH > 4,5: lay 10 ml mau vao erlen them 3 giotphenolphthalein. Dung dung dch NaOH 0,02 N nh phan en khi dung dch va comau tm nhat. Ghi nhan the tch V2 ml dung dch NaOH a dung, tnh o acid tong

cong.

Lam hai Erlen oi chng khi dung ch th Metylcam , cho vao hai Erlenmoi Erlen 20 ml nc cat, Erlen th nhat them 1 ml H2SO4 1N + 3 giot methyl cam.Erlen th hai them 1 ml NaOH 1N + 3 giot methyl cam.

4. Cach tnhV 1000

o acid (mg CaCO3/ l) = --------------------ml mau

Vi V : the tch dung dch NaOH dung nh phan : V1, V2

5. Cau hoi1.Mau nc co pH = 7,3 va ham lng HCO3- la 30 mg/ l. Gia s rang anh hngcua chat ran hoa tan tren hoat tnh cua cac ion khong ang ke, nhiet o cua nc la250C. Tnh ham lng CO2 cua mau nc.


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2.Nc cap co ham lng HCO3- la 30 mg/ l va ham lng CO2 la 30 mg/l. Tnh pHcua nc nhiet o 250C. Neu ham lng CO2 cua mau giam con 3 mg/ l bi suckh, pH cua nc luc nay la bao nhieu?

BAI 9:O KIEM

1. Gii thieu chung1.1. Y ngha moi trngo kiem bieu th kha nang thu nhan proton H+ cua nc. Nc thien nhien hay nct he thong cap nc, o kiem eu do 3 ion chnh tao ra: hydroxide, carbonate vabicarbonate. Trong thc te cac muoi acid yeu nh borate, silicate cung gay anhhng ln en o kiem. Mot vai acid hu c ben vi s oxy hoa sinh hoc nh acidhumic, dang muoi cua chung co kha nang lam tang o kiem. Trong ieu kien thiennhien thch hp, tao de dang xuat hien va ton tai oi vi mot vai nguon nc mat,qua trnh phat trien va tang trng cua tao giai phong mot lng ang ke carbonate

va bicarbonate lam cho pH nc tang dan co the len en 9 10. nhng nguon ncc x ly vi hoa chat co cha nhom carbonate cung lam gia tang pH.

1.2. Nguyen tacTien hanh nh phan o kiem vi ch th phenolphtalein va methyl cam (hoac

ch th hon hp bromoresol luc + methyl o) trong tng giai oan va tuy trng hp:Ch th phenolphtalein se co mau tm nhat trong moi trng co ion hydroxide

va ion carbonate, mau tim se tr nen khong mau khi pH < 8,3.Ch th methyl cam cho mau vang vi bat ky ion kiem nao va tr thanh mau

o khi dung dch tr thanh acid. Viec nh phan c xem la hoan tat khi dung dch

co mau da cam (pH = 4,5), nam gia mau vang (moi trng baz) va mau o (moitrng acid). Do o mau iem ket thuc thng c so sanh vi hai ong chuan.V s oi mau cua methyl cam kho nhan thay, nen ch th hon hp

bromocresol luc + methyl o co khoang oi mau ro rang hn cung tr so pH nenthng c s dung rong rai hn.1.3. Cac tr ngai

Lng chlorine d trong nc uong anh hng en ket qua nh phan lamnhat mau chat ch th. e tranh sai lech, ta cho them vao mau mot vai giot Na2S2O30,1 N. Khi mau nc co o mau va o uc cao phai dung phng phap chuan oien the. Nhng chat ket tua, xa bong, chat dau, chat ran l lng co the phu iencc thuy tinh lam cho iem cuoi en cham. e khac phuc hien tng nay cn phichui schin cc moi khi tien hanh th nghiem. Khong loc, pha loang hay co acmau.

2. Dung cu thiet b va hoa chat2.1. Dung cu va thiet b02 Erlen 150 ml


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01 Ong ong 100 ml01 Buret 25 hoac 50 ml

2.2. Hoa chatDung dch sulfuric acid (H2SO4) 0,02 N: pha dung dch H2SO4 1N (28 ml H2SO4

amac + nc cat = 1 lt), lay 20 ml dung dch H2SO4 1N + nc cat = 1 lt. nh

phan lai acid nay bang Na2CO3 0,02N (hoa tan 1,06g Na2CO3 a say 1050C valam nguoi trong bnh hut am + nc cat = 1 lt).

Ch th mau phenolphthalein 0,5 %Ch th mau methyl cam 0,5 %Ch th mau hon hp bromocresol luc + methyl o: 20 mg methyl o + 200mg

bromocresol + 100 ml ethanol 95%

3. Thc hanhNeu mau co pH > 8,3: lay 10ml mau vao erlen, them 3 giot ch th mau

phenolphthalein. nh phan bang dung dch H2SO4 0,02N cho en khi mat mau. Ghithe tch V1 ml H2SO4 0,02N a dung e tnh O KIEM PHENOL(P).Neu mau co pH < 8,3: lay 10 ml mau vao bnh tam giac, them 3 giot ch th

mau methyl cam (hay 3 giot ch th mau hon hp). nh phan mau bang dung dchH2SO4 cho en khi dung dch co mau da cam (mau gia hai Erlen oi chng). Neudung ch th hon hp, tai iem ket thuc dung dch co mau o xam. Ghi the tch V2mlH2SO4 0,02N a dung e tnh O KIEM METHYL CAM hay O KIEM TONGCONG.

Lam hai Erlen oi chng khi dung ch th Metylcam , cho vao hai Erlenmoi Erlen 20 ml nc cat, Erlen th nhat them 1 ml H2SO4 1N + 3 giot methyl cam.

Erlen th hai them 1 ml NaOH 1N + 3 giot methyl cam.

4. Cach tnhV1 1000

o kiem PHENOL (mg CaCO3/l) =ml mau

V2 1000o kiem tong cong T (mg CaCO3/l) =

ml mauDa tren ket qua co the tnh o kiem do cac ion khac nhau gay ra theo bang sau:

Ket qua phan nh o kiem do cac cac ion (mg/lCaCO3)OH- CO32- HCO3-

P = 0 0 0 TP < T/2 0 2P T 2PP = T/2 0 T-2P 0P > T/2 2P - T 2(T P) 0P = T T 0 0


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P o kiem phenolT o kiem tong congOH- (mg/l) = o kiem OH- (mgCaCO3/l) 0,34CO32-(mg/l) = o kiem CO32 (mgCaCO3/l) 0,6HCO3-(mg/l) = o kiem HCO32 (mgCaCO3/l) 1,22

5. Cau hoiGia s rang anh hng cua cac muoi hoa tan tren hoat tnh cac ion khong ang ke.Mot phan nc 250C co pH = 10,3 va ham lng carbonate la 120 mg/l.- Hay tnh ham lng ion bicarbonate (mg/l).- Tnh o kiem OH, CO32, HCO3 va o kiem tong cong cua mau tren (mg/lCaCO3).

BAI 10:O CNG TONG CONG

1. Gii thieu chung

1.1. Y ngha moi trngo cng c hieu la kha nang tao bot cua nc vi xa bong. Ion calci va magnestrong nc se ket tua vi xa bong, do o lam giam sc can be mat va pha huy actnh tao bot. Nhng ion dng a hoa tr khac cung co the ket tua vi xa bong,nhng thng nhng ion nay di dang phc chat, hoac la chat hu c, do o anhhng cua chung trong nc khong ang ke va kho xac nh. Tren thc te, o cngtong cong c xac nh bang tong ham lng calci, magnes va c bieu th bangmg CaCO3/l1.2. Nguyen tac (phng phap nh phan bang EDTA)Ethylenediaminetetraacetic acid (EDTA) hoac muoi natri dan xuat (Na-EDTA) khi

them vao dung dch cha nhng ion kim loai a hoa tr dng, pH 10,0 0,1 se taothanh cac phc chat. oi vi hai ion calci va magnes chu yeu gay o cng trongnc, neu co mot lng nho ch th mau hu c nh Eriochrome Black T (EBT) haycalmagite c cho vao, dung dch tren se tr nen mau o ru vang. nh phanbang EDTA, phn ng tao phc gia EDTA vi ion calci, magnes se lam chuyenmau dung dch t o ru vang sang xanh dng tai iem ket thuc.1.3. Cac anh hng

Mot vai ion kim loai nang gay tr ngai cho viec nh phan, lam ch th maunhat dan hay khong ro rang tai iem ket thuc. Co the khac phuc tr ngai nay bang

cach them chat che luc nh phan. Muoi Mg-EDTA co tac dung nh mot chat phanng kep va tao phc vi cac kim loai nang, va giai phong Mg vao trong mau, cothe dung thay the cho cac chat che co mui kho chu va oc tnh. Muoi Mg-EDTAch co tac dung tch cc khi thay the cho cac kim loai nang song khong lam bien oio cng tong cong trong mau nc.

Bang di hng dan cach s dung chat che tuy thuoc ham lng kim loainang hay lng polyphosphate co trong mau, giup viec xac nh Ca va Mg bangphng phap EDTA; o cng tong cong se co c qua phng phap tnh.


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Ham lng toi a cac chat gay nhieu can loai bo bi chat cheChat gay tr ngai Ham lng toi a chat gay tr ngai(mg/l)

Chat che 1 Chat che 2NhomBasiumCadmiumCobaltongSatChMangness (Mn2+)NiekelStrontiumKemPolyphosphate

20++Tren 20Tren 30Tren 30++Tren 20++

20++0,32052010,3+20010

Lieu lng tren ch thch hp vi 25 ml mau pha loang thanh 50 ml.Nhng lu y khi nh phanViec nh phan ch thc hien nhiet o phong hay gan vi nhiet o phong,

tranh s cach biet nhiet qua ln so vi nhiet o moi trng xung quanh. S oi mautr nen cham va ket qua kem chnh xac nh trong trng hp mau c nh phangan khoang nhiet o ong ac. Chat ch th mau se b phan huy trong nc nong.ac biet pH co the tao ra moi trng dan en tua CaCO3, tuy nhien nh phan colau cung co the hoa tan lai ket tua. S thay oi cham tai iem ket thuc thng choket qua thap hn. Nham giam thieu ket tua CaCO3 tao thanh. Viec nh phan canhoan tat trong vong 5 phut. Ba phng phap sau ay lam giam ket tua CaCO3.

Pha loang mau bang nc cat e toi giam lng CaCO3. Dung mot lngmau qua nho de dan en sai lech khi oc ket qua tren than ong nho giot.

Neu o cng a c biet hay a c xac nh bang phng phap nh phans bo. Them nhanh EDTA vi khoang 90% lng can dung hay mot t le thch nghituy vao the tch mau can nh phan trc khi chnh pH bang dung dch em.

Acid hoa mau va khuay trong vong 2 phut e uoi CO2 trc khi chnh pHxac nh o kiem sau moi lan them axit.

2. Dung cu, thiet b va hoa chat

2.1. Dung cu va thiet b02 Coc 250 ml01 Buret 10 ml01 Erlen 100 ml01 Ong ong


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2.2. Hoa chat2.2.1.Dung dch ema. Hoa tan 16,9g NH4CL trong 143 ml NH4OH am ac + 1,25g muoi Mg- EDTA +nc cat = 250 mlb. Neu khong co muoi Mg- EDTA, hoa tan 1,179g muoi Na-EDTA(PA) + 780 mgMgSO4.7H2O hoac 644 mg MgCl2. 6H2O trong 50 ml nc cat.

Hoa tan 16,9g NH4Cl trong 143 ml NH4OH am ac.Tron eu hai dung dch tren va pha loang thanh 250 ml vi nc cat.e at o chnh xac cao can gi ung t le ve phan lng gi cac hoa chat tren.ng cac dung dch tren trong chai nha deo hay chai thuy tinh trung tnh. Thi hans dung khong qua mot thang. ay nap kn e ngan NH3 bay hi va CO2 ngoaikhong kh khong xam nhap vao dung dch.Them vao mau 1- 2 ml dung dch em, neu dung dch mau nh phan cha at tipH 10,0 0,1 tai iem ket thuc chuan o.2.2.2.Nhng tac nhan che

Phan ln cac loai nc khong can them tac nhan che. Tuy nhien mot vai mau nccha nhng ion gay nhieu, can them tac nhan che e lam s oi mau tai dt iemc ro rang. Sau ay la nhng chat che thch hp.Chat che IMau co tnh acid phai c trung hoa ti khi pH = 6 bang dung dch em hay NaOH0,1N trc khi them 200 mg sodium cyanide (NaCN) di dang tinh the. Them udung dch em e co pH 10 0,1. (Chu y: NaCN rat oc. Can than khi s dung no.Xa that nhieu nc trc khi o bo dung dch tren e tranh phan ng toa hi ochydroxyanide (HCN).Chat che II

Hoa tan 5g NaS. 9H2O hay 3,7g Na2S. 5H2O trong 100 ml nc cat.Dung dch Na2S de b oxy hoa bi kh tri tao ra ket tua sulfide anh hng en viecxac nh iem chuyen mau chat ch th. Phai bao quan dung dch nay trong chai aykn bang nut cao su. Khi biet ro co s hien dien cua cac kim loai nang, s dung chatche x ly mau trc khi nh phan (xem phan nhng lu y khi nh phan)2.2.3. Chat ch th maua. Eriochrome Black T : muoi natri dan xuat t 1 (1 hyroxy 2 naphthylazo 5nitro 2 naphthol 4 sulfonic acid), hoa tan 0,5 g ch th tren 100 g 2, 2 ,, 2,, -nitrilotriethanol. Them hai giot cho moi 50 ml mau. Chnh the tch mau nc canthiet.b. Calmagite: 1 (1 hydroxy 4 methyl 2 phenylazo) 2 napthol 4 sulfonic acid.Calmagite thch hp cho dung dch long va tao ra s thay oi mau tng t nhEryochrome Black T. vi iem ket thuc ro rang hn. Hoa tan 0,10 g Calmagite trong100ml nc cat. Dung 1ml cho moi 50 ml mau nh phan. Chnh the tch neu canthiet.c. Chat ch th I va II co the dung di dang tinh the kho. Khong nen dung chat chth qua nhieu. Chan b hon hp kho cua chat ch th di muoi tinh thiet.


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d. Neu tai iem ket thuc chuan o, s thay oi mau cua ch th khong ro rang trongtrng hp nay can phai them tac nhan che. Neu cho chat che NaCN vao mau maiem oi mau van khong ro rang, nguyen nhan co the do chat ch th mau b h.2.2.4. Dung dch chuan EDTA 0,01 M

Can 3,723g EDTA. Hoa tan trong nc cat va pha thanh 1000 ml, chuan olai bang dung dch Calcium.

Dung dch chuan EDTA phai c ng trong chai thuy tinh trung tnh haybnh nha polyethylen.2.2.5. Dung dch chuan CalciumCan 1g CaCO3 (dung chat chuan tot nhat hay hoa chat at biet co ham lng cackim loai nang, o kiem va magnesium thap) vao trong mot erlen 500 ml. at motcai pheu tren mieng bnh, moi lan them mot t HCl cho ti khi tat ca CaCO3 tanhoan toan. Them 200 ml nc cat va un soi vai phut e oi CO2 lam lanh va themvai giot ch th methyl o, chnh lai pH en khi co mau cam bang NH4OH 3N hayHCl chuyen qua bnh nh mc va pha thanh mot lt vi nc cat: 1 ml = 1 mg

CaCO3.2.2.6. Dung dch sodium hydroxide: NaOH 0,1 N

3. Trnh t th nghiemLay mot the tch mau sao cho lng EDTA chuan o khong qua 15 ml, hoan

thanh viec nh phan trong vong 5 phut tnh t thi iem cho dung dch em. Neulng EDTA ln hn 15ml th phai pha loang mau.

Lay 25ml mau, them 1 ti 2 ml dung dch em, thng dung 1 ml u e atpH 10 0,1, them chat che neu s thay oi mau tai iem ket thuc chuan o khongro rang. Sau khi them chat che nhng mau the hien van khong ro rang. Chat ch th

co the a b hong.Them chat ch th mau (lng nho bang 1/5 hat gao). Chuan o t t bangdung dch EDTA cho en luc co mau xanh da tri lai iem ket thuc . Neu the tchmau co u va khong co chat gay can tr th tr so nh phan se tang khi s dung 1lng mau nhieu hn c mieu ta trong phan c di ay.

Mau co o cng thap: nc sau khi qua trao oi ion, cac loai nc mem khacva cac loai nc thien nhien co o cng thap ( t hn 50 mg/l) can lay mot the tchln hn (100 1000 ml) e nh phan va them vao mot lng dung dch em. Chatche. Chat ch th mau theo t le tng ng. Chuan o bang ong nho giot nh phannho nhat, lam them mau th khong: dung nc cat 2 lan nc qua cot trao oi ionbang the tch mau. Lng dung dch em, chat che, chat ch th mau tng t nhmau. Lay the tch EDTA nh phan cua mau tr i the tch dung nh phan cho mauth khong.

4. Cach tnh( A B 1000)

o cng (EDTA) mg CaCO3/l = .........


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ml mauTrong o:

A ml EDTA tham gia phan ng trong mauB mg CaCO3 tng ng 1 ml EDTA nh phan.

5. Cau hoi1. Nguyen nhan gay ra o cng cua nc?2.Mau nc c phan tch co cac ket qua nh sau:

Na+ = 20mg/l Cl- = 40 mg/lK+ = 30 mg/l HCO3- = 40 mg/lCa2+ = 15 mg/l CO32- = 67 mg/lMg2+ = 10 mg/l SO42 = 5 mg/lSr2+ = 2 mg/l NO3- = 10 mg/l

Tnh o cng tong cong, o cng carbonate, bicarbonate cua mau nc; (n vmgCaCO3/l)

BAI 11: O CNG CALCI

1. Gii thieu chungCalci la mot nguyen to thng gap trong nc thien nhien v chay qua nhng

vung co nhieu a voi, thach cao, dolomit Tuy theo nguon goc va cach x ly maham lng calci trong nc co t 0 en vai tram mg/l. Ch vi mot lng nhocalcicacbonate cung co the tao nen mot mang cng bam vao mat trong cac ong dantheo thi gian tch tu, bao ve kim loai chong lai s an mon. Mat khac, lp mang naylai la mot tai hai ln cho nhng thiet b s dung nhiet o cao nh noi hi

Phng phap lam mem nc bang hoa chat hoac nha trao oi ion thng c apdung e kh bt calci ti gii han chap nhan c

2. Nguyen tacTrong dung dch co cha calci va magnes, pH=12-13, magne se b ket tua didang hydroxy. Chat ch th mau ket hp vi calci cho mau hong. Khi EDTA cthem vao dung dch se ket hp vi calci va phan ng xay ra hoan toan. iem ketthuc dung dch chuyen mau hong sang tmCAC ANH HNG (XEM PHAN O CNG)

3. Dung cu, thiet b, hoa chat3.1. Dung cuErlenPipetBuretOng ong


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3.2. Hoa chatDung dch NaOH 1NCh th mau Murexider: Can 200g murexider + 100g NaCl nghien nho, tron euDung dch EDTA 0.01M: Xem phan o cng4. Thc hanhe tranh ket tua, viec nh phan can thc hien nhanh chong sau khi nang pH

a. Lay 25ml (hay mot the tch mau pha loang en 25ml) sao cho the tch EDTAdung nh phan khong vt qua 15ml. Neu mau nc co ham lng calci vt qua300mg/l nen pha loang hoac trung hoa vi acid roi un soi mot phut, lam nguoitrc khi nh phan.b. Them 2ml dung dch NaOH 1N hoac mot the tch ln hn e nang pH len 12-13,lac euc. Them 0,1-0,2g ch th mau murexider (lng nho bang 1/5 hat gao), dung dch comau hong nhatd. nh phan bang dung dch EDTA 0,01M, iem ket thuc dung dch co mau tm. e

kiem soat iem ket thuc chuan o, can ghi nhan the tch EDTA a dung, sau othem mot hoac hai giot EDTA e am bao mau cua dung dch khong oi

5. Cach tnh

Calci (mg/l) =mlmau

VMlEDTA 8,400

o cng calci (mgCaCO3/l) =mlmau

VmlEDTA 1000

BAI 12: NITROGEN ORGANIC

1. Gii thieu chung1.1. ai cng

Viec xac nh Nitrogen hu c bang phng phap Kjeldahl khong tnh ennit cac dang khac nh: azide, azo, hydrazone, nitrate, nitrite, nitro, nitroso, oximeva semi carbazone. Neu nitrogen ammonia khong c kh trc th phng phapnay cho ket qua la lng nitrogen tong cong. V the, muon xac nh lng nitrogenhu c can xac nh rieng nitrogen ammonia trc sau o tien hanh chng cat tieptheo.

1.2. Nguyen tacVi s hien dien cua acid sulfuric, potassium sulfate va mercuric sulfate lam

chat xuc tac, amino-nitrogen cua nhng chat hu c c bien oi thanh ammoniumsulfate. Ammonia t do va ammonium-nitrogen cung chuyen thanh ammoniumsulfate. Trong thi gian phan huy mau, hon hp mercury ammonium c hnhthanh va b phan tch bi Na2S2O3. Sau o trung hoa mau bang dung dch kiem vachng cat. Ham lng ammonia hu c c hap thu bang acid boric va xac nh


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bang phng phap so mau hay chuan o vi acid chuan tren the tch chng catpham thu c.Phng phap so mau xac nh ham lng N-Organic thap khoang 5mg/l.Phng phap chuan o xac nh ham lng N-Organic ln hn 5mg/l.2. Dung cu, thiet b va hoa chat2.1. Dung cu va thiet b- Thiet b phan huy bnh Kjeldahl 800 ml dung phan huy mau di tac dung cua motdung dch phan huy (acid manh) va un nhiet o 370oC.- Thiet b chng cat :he thong chng cat gom mot dan Kjeldahl vi 6 bnh Kjeldahl800 ml c noi vi he thong lam lanh ngng tu. Hi ammonia bay ra c hap thubang dung dch acid boric.- Buret 25ml.- Erlen 500 ml .- Ong ong 250 ml.2.2. Hoa chat

2.2.1. Ch th hon hpHoa tan 200 mg methyl red vao 100 ml ethyl alcohol (hoac isopropyl alcohol) +dung dch 100 mg methylene blue trong 50 ml ethyl acohol. Hoa hai hon hp lai,dung dch s dung trong mot thang.2.2.2. Dung dch acid boric (H3BO3)20 g acid boric +nc cat = 1 lt + them 10 ml ch th mau e dung dch co mau tm.2.2.3. Dung dch acid sulfuric (H2SO4) 0,02 N2.2.4. Dung dch mercuric sulfate

Hoa tan 8 g oxit thuy ngan o HgO trong 100 ml H2SO4 6N.2.2.5. Dung dch phan huy (acid manh )

Hoa tan 134g K2SO4 trong 650 ml nc cat + 200 ml H2SO4 am ac. Themvao dung dch Mercuric sulfat a ieu che san gom 2g HgO (mercuric oxid red)trong 25 ml ,quay eu + Them nc cat cho u mot lt. Gi nhiet o thap gan20oC.2.2.6. Dung dch borate

Them 88 ml NaOH 0,1N vao 500 ml dung dch tetraborate Na2B4O7 0,25 M(9,5g Na2B4O7. 10H2O/ lt ) va pha loang thanh mot lt.2.2.7. Dung dch sodium hidroxide (NaOH) 6N

Hoa tan 240g NaOH vien trong mot lt nc cat.

2.2.8. Dung dch sodium hidroxide sodium thiosulfateHoa tan 500g NaOH va Na2S2O3.5 H2O bang nc cat va pha thanh 1lt.

3. Thc hanh3.1. Chuan b va chon the tch mau thch hp theo bang hng dan sau

Lng Nitrogen trong mau(mg/l)

The tch mau (ml)


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0 -11 -10

10 2020 - 50

50 100

5002501005025

Neu can pha loang mau thanh 300 ml roi trung hoa en pH = 7.

3.2. Them 25ml borate buffer va NaOH 6N en pH = 9,5. Chng cat va xac nhlng ammonia-nitrogen bang the tch chng cat pham thu c (hap thu vi 25mlacid boric + vai giot ch th mau hon hp). Dung can con lai trong bnh Kjeldahl exac nh lng Nitrogen hu c.3.3.Phan huy: Can than them 50ml dung dch phan huy vao bnh kjeldahl co chacan con lai + vai vien bi thuy tinh va un nong trong tu hut hay trong mot thiet b cothe loai bo khoi acid bay ra. Tiep tuc un cho en khi thay khoi trang bay ra, dungdch co mau vang rm va trong. e nguoi, pha loang thanh 300ml vi nc cat roitrung hoa bang dung dch sodium hiroxie thiosulfate (khoang 30 40ml. dung

phenolphtalein lam ch th mau) lac eu, oi khi thay xuat hien tram en cua HgS.pH cua mau luc nay khoang 11,0.3.4. Chng cat: noi bnh Kjeldahl vao he thong chng cat, au ra nhung chm trong25ml acid boric, chng cat en khi chng cat pham thu c khoang 200ml. Sau onh phan bang HCl 0,1N hay H2SO4 0,1N. Lam mot mau th khong vi nc cat.

4. Cach tnh

(mg) N-hu c =mlmau

VV ot 140)(

Vt : the tch HCl 0,1N dung cho th that.Vo : the tch HCl 0,1N dung cho th khong.

5. Cau hoi5.1. Y ngha moi trng cua viec xac nh nitrogen organic5.2. Tai sao muon xac nh nitrogen organic phai s dung phng phap chng catva phai nang pH = 9,5


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CHNG 4PHAN TCH CAC THONG SO TRAC QUANG

BAI 13:SAT

1.Gii thieu chung1.1. Y ngha moi trng

T lau con ngi a nhan biet, uong nc co cha sat se khong gay hai oivi sc khoe. Nc mat sau khi loai bo can l lng th ham lng sat t khi at ti1mg/l. Rieng oi vi nc ngam va nc thai sinh hoat, ham lng sat co the caohn rat nhieu. Nhng loai nc nh the khi tiep xuc vi khong kh se tr nen uc vaco mau vang, nguyen nhan la do sat dang Fe2+ b oxy hoa thanh Fe3+ tao ra nhngchat ket tua di dang keo. nhng ieu kien t nhien va pH thap, toc o cua quatrnh oxy hoa thng xay ra cham va sat trong nc thng ton tai di dang Fe2+.Trong moi trng pH < 6 va co suc kh, Fe3+ co the ton tai mot thi gian. Toc o

oxy hoa se tang len khi trong moi trng co pH > 6, co mat cua cac chat oxy hoahay do hoat ong cua vi sinh vat. Sat co trong nc la nguyen nhan lam cho quanao b vang sau khi giat, lam o cac o vat bang s va tao ra cac vet o tren cac o vathan ch. Khi ham lng sat trong nc ln hn 1mg/l gay ra v tanh trong nc vave mat cam quan khong the chap nhan c. Ngoai ra, can sat bam tren thanh ongdan lau ngay lam thay oi lu lng va tac cac ong dan cua he thong phan phoinc. Chnh v nhng ly do tren nen tieu chuan at ra cho nc s dung trong sinhhoat va an uong phai co ham lng Fe tc


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Phng phap phenanthroline co the xac nh ham lng sat ln nhat la 1mg/l1.3. Tr ngai

Nhng chat oxy hoa manh nh cyanide, nitrite va phosphate (polyphosphatemanh hn orthophosphate), chromium, zine vi ham lng ln hn sat 10 lan,cobalt, copper ln hn 5mg/l va nicken ln hn 2 mg/l eu gay anh hng en ketqua phan tch. Bismuth, cadmium, mercury, molybdate va silver ket tua vi

phenanthroline. Trong qua trnh thc hien th nghiem, bc un soi vi acid nhamchuyen polyphosphate thanh orthophosphate, loai bo anh hng cua nitrite vacyanide. Them mot lng tha phenanthroline e loai bo nhng sai so gay ra bicac chat oxy hoa manh va tao phc vi mot so ion kim loai co trong dung dch. Neuham lng cac ion kim loai qua cao, can phai s dung phng phap trch ly.

Neu mau co mau hay chat hu c, x ly mau bang cach un soi mau nhieugi vi acid HCl 1:1 trong coc co quai bang silica, s hay platinum. Khi mau can,ot nhe, phan tro con lai c hoa tan bang acid. Neu ham lng chat hu c quacao, bc phan huy se c thc hien trc giai oan trch ly.

2 . Dung cu, thiet b va hoa chat2.1. Dung cu va thiet b2.1.1. Dung cuDung cu thuy tinh: nham loai bo sat bam tren thanh dung cu can phai ra tat cadung cu thuy tinh bang acid HCl am ac, trang lai bang nc cat trc khi s dung.

+ 02 Erlen 125ml+ 01 Ong ong 50ml+ 06 Bnh nh mc 100ml+ 02 pipet 2ml, 5ml, 10ml

+ 01 pipet 25ml2.1.2.Thiet b:

+ Spectrophometer+Bep ien

2.2. Hoa chat:S dung nhng hoa chat co ham lng sat thap va nc cat khong co sat e chuanb cac dung dch chuan va tac nhan.2.2.1.. Hydrochloric acid (HCl) am ac.2.2.2.Dung dch hydroxylamine:hoa tan 10g NH2OH.HCl trong 100ml nc cat.2.2.3. Dung dch em ammonium acetate (NH

4CH

3COOH): hoa tan 250g

NH3C2H3O2 trong 150ml nc cat, them 700ml acid acetic (CH3COOH) am ac.Lac eu nh phn bng nc ct n 1000ml.2.2.4. Dung dch phenanthroline:Cach 1: hoa tan 100mg 1,10 phenanthroline (C12H8N2.H2O) trong 100ml nc cat,khuay va un ti 80oC. Khong c un soi.Cach 2: cho 10ml nc cat vao trong coc cha 100mg phenanthroline C12H8N2.H2O,them 2 giot acid am ac, khuay eu en khi tan hoan toan, pha loang thanh 100ml.


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Khong s dung khi dung dch co mau.2.2.5. Dung dch lu tr sat: (500ppm)o 20ml H2SO4 am ac vao 50ml nc cat va them vao 1,7594gFe(NH4)2(SO4)2.6H2O. Sau khi dung dch ong nhat. Pha thanh 500ml vi nc cat(1,00ml = 500g Fe).2.2.6. Dung dch chuan:Lay 20ml dung dch lu tr sat cho vao bnh nh mc 1000ml, them nc cat tivach nh mc (1,00ml = 10,00g Fe).

3. Thc hanh3.1. Sat tong cong (Fe tc)

Mau phai c lac eu trc khi phan tch, lay 50ml mau cho vao erlen. Neuthe tch mau co ham lng sat cao hn 200g, s dung mot lng mau t hn va phathanh 50ml. Them 2ml HCl am ac va 1ml NH2OH.HCl. Them vai vien bi thuytinh vao erlen, un soi en khi the tch con khoang 15 20ml (neu mau b can, cho

vao 2ml HCl am ac va 5ml nc cat).Lam nguoi mau nhiet o phong, chuyen dung dch vao bnh nh mc100ml, them 10ml dung dch em NH4CH3COOH va 4ml dung dch phenanthroline.Cho nc cat ti vach nh mc va lac eu, sau o e khoang 10 15 phut chocng o mau at cc ai va on nh. o o hap thu tren may spectrophotometer bc song 510nm.3.2. Sat hoa tan

Ngay sau khi lay mau, loc mau bang giay loc co ng knh 0,45 m, ncsau loc c acid hoa vi t le 1ml HCl am ac/100ml mau. Tong ham lng sathoa tan c xac nh nh trong phan 3.1.

3.3. Sat hai (Fe2+)Viec xac nh Fe2+ phai thc hien tai v tr lay mau bi v co s thay oi ty le

gia Fe2+ va Fe3+ theo thi gian trong moi trng acid. e xac nh Fe2+, acid hoamau theo t le 2ml HCl am ac/100ml mau tai thi iem lay mau.

Lay 50ml mau a c acid hoa, them 20ml phenanthroline va 10ml dungdch em NH4C2H3O2, lac eu. Pha thanh 100ml vi nc cat, i khoang 1015phut, sau o o o hap thu A bc song 510nm.


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4. Cach thanh lap ng cong chuanS dung dung dch chuan co nong o 1ml = 10g Fe.Pha loat dung dch chuan sat nh sau :

STT0 1 2 3 4 5

V dd chuan (ml) 0 2 4 6 8 10

V nc cat (ml) 50 48 46 44 42 40V dd em ammonium acetateNH3C2H3O2 (ml)

10

V dd phenanthroline (ml) 4** nh mc 100mlHam lng Cg 0 20 40 60 80 100Nong o C mg/l 0 0,2 0,4 0,6 0,8 1,0o hap thu A (o bang may)bc song 510nm.

zero ? ? ? ? ?

Chu thch** nh mc thanh 100ml bang nc cat. Lac eu va o o hap thu.Neu mau b uc va co mau, thay v s dung nc cat lam mau chuan trang, s dungchnh mau lam mau chuan trang va x ly mau qua tat ca cac bc nh trong quatrnh thc hien nhng khong cho phenanthroline.

Day chuan sat5. Tnh toan

Sau khi co o hap thu cua mot loat chuan. Ve gian o A = f(C), s dung

phng phap bnh phng cc tieu e lap phng trnh y= ax + b. T tr so o hapthu cua dung dch mau Am suy ra Cm t phng trnh tren. Ket qua bieu dien bangn v mg/l.

6. Cau hoi6.1.Trnh bay nhng trang thai khac nhau cua sat trong nguon nc t nhien, neuieu kien ton tai cua moi trang thai.


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6.2.Neu nhng nguyen nhan chnh gay o nhiem sat trong nguon nc ngam.


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BAI 14: NITROGEN NITRITE (N NO2)

1. Gii thieu chung1. 1 Y ngha moi trngNitrite la mot giai oan trung gian trong chu trnh am hoa do s phan huy cac chatam hu c. V co s chuyen hoa gia nong o cac dang khac nhau cua nitrogen

nen cac vet nitrite c s dung e anh gia s o nhiem hu c. Trong cac he thongx ly hay he thong phan phoi cung co nitrite do nhng hoat ong cua vi sinh vat.Ngoai ra nitrite con c dung trong nganh cap nc nh mot chat chong an mon.Tuy nhien, trong nc uong, nitrite khong c vt qua 0.1 mg/l.1.2 Nguyen tacNitrite c xac nh bang phng phap so mau. Mau do phan ng t cac dung dchtham chieu va mau sau khi tac dung vi acid sulfanilic va naphthylamine moitrng pH = 2 2.5 tao thanh hp chat mau o tm cua acid azobelzolnaphthylamine sulfonic nh sau:

HSO3- -NH3 + NaNO2 HSO3- -N=N+Cl- + NaCl + H2O

Phng phap DIAZO thch hp khi xac nh ham lng N-NO2 t lg/25-1 1.3 Cac nh hngChlorine va nitrogen trichloride ton tai trong mau se gay ra tr ngai oi vi phngphap nay. Anh hng nay se giam thap khi them naphthylamine hydrochloridetrc, sau o en acid sulfanilic. Nhng ion tao ket tua lam sai lech ket qua nh:Sb, Fe3+, Pb2+, Hg2+, Ag+, khong nen ton tai trong mau. Mot lng nho chat ran llng cung gay can trm co the loc qua giay loc kch thc m0.45

2. Dung cu, thiet b va hoa chat2.1 Dung cu va thiet b2.1.1 Dung cuPipet 1ml (1); ong ong 50ml (1); pipet 25ml (1)Erlen 125ml (9); qua bop cao su (1)Coc ot 100ml (1)SpectrophotometerOng o o truyen suot

2.1.2 Hoa Chata. Dung dch chuanDung dch lu tr N-NO2: (1ml = 250 g N-NO2): NaNO2 0.05: hoa tan 1.232gNaNO2 trong nc cat va nh mc thanh 1000ml.Dung dch N-NO2 chuan (1ml = 0.0005mg = 0.5 g N-NO2): Lay 2ml dung dch lutr + nc cat = 1 lt.Xac nh lai nong o dung dch NO2- mi pha bang cach pha cac dung dch sau:


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KMnO4 0.05N: can 1.6g KMnO4 + nc cat = 1 lt.FAS 0.05N: can 19.607g Fe(NH4)2(SO4)2.6H2O + 20ml H2SO4 am ac + nc cat =1 lt.Na2C2O4 0.05N: can 3.350g Na2C2O4 the6m nc cat cho u 1 lt (neu khong dungFAS).Cho vao bnh thuy tinh co mai 50ml KMnO4 0.05N va 5ml H2SO4 am ac, them

50ml dung dch NaNO2 0.05N (hoac Na2C2O4 0.05N) vi dung dch bang cach themmoi lan 10ml dung dch FAS (hoac Na2C2O4) vi dung dch KMnO4 0.05N en khidung dch chuyen sang mau hong nhat. Tnh nong o cua dung dch lu tr N-NO2bang cong thc:

F

EDCBA

7*)]*()*[( = mg/ml N-NO2

B ml dung dch KMnO4 a dungC nguyen chuan o cua dung dch KMnO4 (0.05N)D ml FAS (hoac Na2C2O4) a dungE nguyen chuan o cua dung dch chuan (0.05N)F ml dung dch NaNO2 dung nh phanb. Dung dch EDTA: can 0.5g muoi natri dan xuat t EDTA + nc cat = 100mlc. Acid sulfanilic + 70ml nc nong e nguoi + 20ml HCl am ac pha loang thanh100ml vi nc cat.d. Dung dch Naphthylamine chlohydrate: can 0.6g naphthylamine chlohydrate +50ml nc cat + 1ml HCl am ac + nc cat = 100ml. Pha dung ngay hoac lu gi nhiet o thap.e. Dung dch em axetat: can 16.4g CH3COONa hay 27.2g CH3COONa.3H2O +

nc cat = 100ml.f. Dung dch huyen treo Al(OH)3: can 125g AlK(SO4)2.12H2O hayAl(NH4)(SO4)2.12H2O trong 1000ml nc cat, un nhe en 600C + 55ml NH4OHam ac. T t lac eu. c 1 gi, ra huyen troc nhieu lan vi nc cat en khinc ra khong con Cl- (th bang AgNO3). Sau o them nc cat cho thanh 1000ml.2.2 Trnh t th nghiemNeu mau th nhieu chat l lng va mau, them 2ml Al(OH)3 vao 100ml mau, elang vai phut, loc bo lp nc qua loc au tien. (Neu mau trong th khong phai lambc nay).

Chuan b mau va dung dch tham chieu (ng chuan) theo bang sau:STT 0 1 2 3 4 5 6(mu)

ml dd N-NO2 chuan(1ml = 0.5 g N-NO2)

0 2.5 5 7.5 10 12.5 0

ml nc cat 25 22.5 20 17.5 15 12.5 -ml mau nc - - - - - - 25


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ml dd EDTA 0.5ml/ongml acid sulfanilic 0.5ml/ong i 10 phutml naphthylamine 0.5ml/ongml dd em axetat 0.5ml/ong i 20 phutC ( g ) 0 1.25 2.5 3.75 5.0 6.25 -C (mg/l) 0 0.05 0.1 0.15 0.2 0.25 -

Cac dung dch theo ung th t trong bang, sau moi lan them dung dch phan ngch ung thi gian qui nh.o o hap thu A bc song nm520= 2.3 Tnh ToanT loat chuan o o hap thu. Ve gian o A = f(C), s dung phng phap bnhphng cc tieu e lap phng trnh y = ax + b.

3. Cau Hoi1. Phan tch mot mau nc ngam, ket qua ham lng nitrite cao, co the ket luan g?

2. Nitrogen thng ton tai dang nao trong nc mat? Nc ngm?

BAI 15:NITROGEN-NITRATE (NO3-)

1. Gii thieu chung1.1. Y ngha moi trng

Nitrate la san pham cua giai oan oxy hoa cao nhat trong chu trnh cuanitrogen, cung la giai oan quan trong trong tien trnh oxy hoa sinh hoc. lp ncmat thng gap nitrate dang vet nhng oi khi rong nc ngam mach nong lai coham lng cao.

Neu nc uong co qua nhieu nitrate thng gay benh huyet sac to tre em.Do o, trong nguon nc cap cho sinh hoat gii han nitrate khong vt qua 6mg/l.1.2. Nguyen tac

Phan ng gia nitrate va brucine cho san pham co mau vang c ap dunge xac nh ham lng nitrate bang phng phap so mau. Cng o mau c o bc song = 410nm. Toc o phan ng gia nitrate va brucine chu anh hng roret vao lng nhiet toa ra trong qua trnh phan ng. V the, cac chat phan ng cthem vao lan lt va u mot khoang thi gian chnh xac tai nhiet o a biet. Nongo acid va thi gian phan ng c la chon e tao mau tot nhat va on nh.

Phng phap nay thch hp vi ca nc ngot va nc bien, vi ham lng N-NO3xap x 0,1-2 mg/l.1.3. Cac anh hng

S hien dien cua tac nhan oxy hoa co the c loai tr bang cach them chatphan ng orthotolidine. Tr ngai bi clor d co the b loai bang mot lng sodiumarsenite khi chlor d khong qua 5 mg/l. Mot lng d sodium arsenite nho khonganh hng en viec xac nh nitrate. Ion Fe2+, Fe3+ va Mn4+ se gay anh hng nhe,


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nhng neu ham lng cac ion nay nho hn 1mg/l th anh hng khong ang ke. Trngai do nitrite gay ra khi N-NO2 < 0,5 mg/l c ngan nga bang acid sulfanilic.Ham lng chat hu c cao trong nc thai cung se gay tr ngai cho viec xac nhnitrate.

2. Dung cu, thiet b va hoa chat

2.1. Dung cu va thiet bOng nghiem 25ml a anh so t 1-5 va 7 ong khac;Pipet 1ml, 2ml, 10ml, 25ml;Hop giay kn hoac tu kn;Spectrophotometer.

2.2. Hoa chat2.2.1. Dung dch N-NO3 chuan: (1ml = 2 g N-NO3)

Dung dch N-NO3 lu tr: (1ml = 2 g N-NO3). Hoa tan 0,7218g AnhydrousPotassium Nitrate KNO3 + nc cat = 1 lt.

Dung dch N-NO3 chuan: (1ml = 0,002mg = 2 g N-NO3). Pha loang 10mldung dch lu tr thanh 500ml e co 1ml dung dch chuan = 2 g N-NO3.2.2.2. Dung dch Brucine-Sulfanilic:Can 1g Brucine Sulfate + 0,1g Sulfanilic Acid trong 70ml nc cat nong, them 3 mlHCl am ac, lam lanh, pha loang thanh 100ml. Gi trong chai am mau 5oC.Dung dch nay co mau hong nhng khong anh hng en ket qua phan tch va cothe dung rong vai thang (chu y: rat oc khong c dung mieng e hut dung dchvao pipet).2.2.3. Dung dch H2SO4 am ac2.2.4. Dung dch Sodium Arsenite (NaAsO2)

Hoa tan 5,0g NaAsO2 vi 1 lt nc cat (chu y: rat oc khong c dungmieng e hut dung dch vao pipet).2.2.5. Dung dch Sodium Chloride

Hoa tan 300g NaCl vi 1 lt nc cat.

3. Trnh t th nghiemNeu mau co chlorine, kh lng clor d nay bang cach them 1 giot sodium arsenitecho moi 0,1mg Cl2 tren 50ml mau.Chuan b dung dch tham chieu nh sau:

STT 1 2 3 4 5 6ml dd N-NO3 chuan(2ppm)

1 2 3 4 5 6

ml nc cat 9 8 7 6 5 4C(g) 2 4 6 8 10 12C(mg/l) 0,2 0,4 0,6 0,8 1,0 1,2

Trong loat ong nghiem khac, can than lay 4ml H2SO4 vao tng ong.


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That chnh xac, trch 1ml dung dch tham chieu cung nh mau vao tng ong nghiemtheo ung so th t tng ong.STT 0 1 2 3 4 5 6 7(mu)ml dd tham chieu 0 1 1 1 1 1 1 -ml nc cat 2 1 1 1 1 1 1 1ml mau nc - - - - - - - 1Dung dch brucine 0,5ml/ongH2SO4 Rot nhanh 4ml dung dch acid a chuan b vao moi

ong ng dung dch N-NO3 chuan va mau. Lac eutng ong

Lac eu. at tat ca vao tu kn hoac hop giay trong bong toi. i 10 phut.Trong thi gian i phan ng hoan tat, hut san 5ml nc cat vao loat ong

nghiem a dung H2SO4 trc o.Sau 10 phut rot nhanh 4ml nc cat vao tng ong nghiem, lac eu. Tiep tuc

e trong bong toi them 20 phut na cho phan ng hoan toan.

o o hap thu A = 410nm.

4. Cach tnhT loat chuan o o hap thu.Ve gian o A = f(C), s dung phng phap bnh phng cc tieu e lap

phng trnhy = ax + b.

T tr so o hap thu Am cua mau tnh nong o Cm.mgNO3/l = mg N-NO3 x 4,43

5. Cau hoi1. Tai sao phai phan tch Nitrate trong kiem tra o nhiem?2. Nitrate co mat trong nguon nc mat, nc ngam, nc cap do nguyen nhan

nao?3. Khi s dung nc co cha nhieu Nitrate co anh hng en sc khoe nh the

nao?

BAI 16:NITROGEN AMMONIA (NH3)

1. Gii thieu chung1.1. Y ngha moi trngS hien hu cua ammonia trong nc mat hay nc ngam bat nguon t hoat ongphan huy chat hu c do cac loai vi sinh vat trong ieu kien yem kh. oi vi nguonnc cap cho sinh hoat, ammonia c tm thay khi b nhiem ban bi cac dong ncthai. Trong mang li cap nc, ammoniac con c s dung di dang hoa chatdiet khuan chloramines nham tao lng chlor d co tac dung keo daithi gian diet


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Phng phap phan tch cac ch tieu moi trng - ThS. inh

phan tich cac chi tieu moi truong - ts dinh hai ha

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