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7 @A, B &A3CD3........ dx.doi.org/10.22093/wwj.2017.45875

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7 * 7 PQB ) 0; * 17 6 9 E5 ! $&@ 7 1Q < RS T!*F E5 $& 99 $& 47K5 9 1 %U7VWX1 /5 E5 9 0E5 >7 9 &$99B)01/ 1'5Y75$994 47; 4* 1'5Y75$/5 7H/ 1 & S ,<1. )1'5 Z/'= 9 H&$9D%$EIJ Z >1 H&

9 H 71$ [& .H / , 1)(LB0\9 $1 ; * 2 &$4LO9*4] 9 1@*4 47/*' 2 H^1 7 H67 7 7 %$U/ )7% 1*' D $G 7 / _IX 49`% 4H9 .4D*

% ) '!/+( ; b (NC/GO-GCE-Ag) /7.1*' / _IX NC/GO-GCE –Ag YB 9 34G 47 9`% " *$ 7 9 $'B%*' *; * c 9 \] **'$4d .H4 4^ 1@* 1S79 ) H 2& &* GeWBeeW !H' d 70pH 9 fBgWHh!C &$@!*F 9 ; * 14( 47WWe/WBgW!7 6/./9`%H U2% 7i $D7(SEM) =4/ ] 4G 034

(XRD) /*' 3 ` 2(EIS) 17FDB .H ^j4kS 4k7 7 -B 7 / *S "1L 1 Hh!CWWe/WBgW!7 7 7 6Wgl/W 6 (S/N=3) =B)/" . NC/GO-GCE-Ag 4U

m& d % ) n 1'B% '! H9 HY- 1 ( $**'$; 4* 1 1 4D .o4* 9 .X)(LB\67 HLX H^1 $ 1 p ] 1 1 D 17 G 7 / *S " $6c1^ ;

,!L 1 1- ; * H &$75!S . hI .7^ H'S1 7 2 ( )=B / .

G! BEB: IF(! FJ"$ BF"+ ;F' IK F (&

!"#$%#

& '()* +, $ - .-* /012 ,- $$% +3 -$4.-* 5 26*7!2 21

$ .,- * 9* 2:; - !2 4<2=$2- $#+% *>,,*?,. 25.-2* @5 =2A: 2-$#

B?) - C$?#"$2- !2 2 +2?".(Korostynska & Moson 2012)

2=D2 .+,% +5 >"#@5"#*22E22- !22FBG 22% !22 H22?I J22%#22- K5 22- L22-* +,22?I $22

!2"#$2%#32M @2N (2* 2"# O2&<& =P:$%!21P . 2 25 2* 2 4Q2: $#

"%#? !"#$%#2 =E9 4< @RS 2"#'2:2 #32M+,2 .-2* B&* =- .,- 2- (2T > 4= K- UB6* !BI


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2- <$ 2E @5 B2 2- +2T $2/I V2: 2BW* #2"+3 @5 #" * +$ * #" 2P5 ,-2% ,2<XY

,&$ *25 @5 ,4H2 @5 !2- 2"#*2!22 225 4@522"#*22 22-=224 225@522"#*25, $ 2 !2 ,2": U2/ 2- 1.(Salem et al. 2011;

Zapata et. 2014; Badeenejad et al. 2012) $ 2"#2B 22&I 2)* $ @5 Z,2?I

$ "#*5"'![ #," % -+3 *

?*5 K%$% +,,$.\D2 +*#$22"-$%#'22<#2222 +32222#22*.22"$* - $ %#+, : < ,!E-

-W DB?I ,$$:- .,$ $ "$ >. 2+ Z/ #- $#]=% $322& @R2S @5 !

* J" 2 .,$52-#12 $2% 02N 4"$2- 4* - 5 K% ^A OE- +_#`2: =$a2

D?N D4U $ "#:$2[ Kbb6* ) $* !222 222 (Casella & Contursi 2014)."'222< #

D?$#$ "#BW* +, #B?) $

22N*#4*22#,22"!P22,22" !22) 22% +,2 2# 25@5+32 2*,2.(Mattarozzi et al.

2013; Stortini et al. 2015) >"'< `: : $ $ c O =E3 dP +,

$ e? - O-[ 3f* +, #]* .," ,2%00"% dP +, $ 2D 2- 2P* 2,2U' 2"#O2-[

+, #*2(Velusamy & Arshak 2010) . 2"D#% 222- +,222 gR222&!222 222"#222h?" K$ (222*>

$$:-# -- 4K5 ! 1 KI"#$ (*$ "#*#WE5 i+, * ",-.(Motahar et al.

2013) gR& -"D >4$2%2< 412 !0j2N#

12 "'2< >2* 0,2-.(Mirmoghtadaei et al. 2013; Remes et al. 2009)

$ 0"_222N 222- 222S<#1222 222< 0!222D4k*%% > OD*4+2b =$a 1B 4,

- , 1 >-% D K5 ?%2 #gR2& ,2 $2F .

* * '< $ $2% +,22F<R* O2-[ #!2) $+, #*#6* $ =7"#-5.,-

! "! #$% ! &

2 2- !`2B:ll/mm ,2&$ !:2 2:$% 2?'n

32+ ., h?">NJ4=B% $34,24,"B%$, 4,, ! 4U 4J* 4+b = 2 O#%*212B .2B[ $2N 4KR#*5 422% d4,,2J

= 4N =J!: !% Q*o+3 K?5 ., OD - 1B B: !T /BN > ?,> $ .

0*5 2" J2 p2 2 O2*T 2q O*2 #2q- 2- >RN q 4.)* q KI 2D?% 2q K2I>-2% 2D 2 #N 2- +,2 gR2& 2k*% 2!

% > 22 OD22*1B22/,s+22b =$a2222- K22I +3 $T q,- . $F*$- 4A* `B:

\ $*#% 1) 2k*% (24!251XRD +32 2- +'Shimadzu XD-3A =2 72 E2- g2S - 4

Cu kα$mt/n22'5$ dθo4t22lu.!22 d22P

22222222M$-#22222222- $SEM +'22222222 722222222JEOL2011microscope >N\ $% !: =$&! .

'(% "! &)* + # ,- !

,- % > ,-+3 $ K2 2*v12 .,2w*B ,xy*$5 - ,&$#* $ Y2z2)$

e22B $ 22- O22:,22 22Wk22 . |*22B22 22,$3w'"5 - ,&$6* - 2 +12 2- K$ =

, *~)$eB , '. d? $ 2 O2<* >$ - UB6*z~Y [ -., + J" b| d ! N 2

J !I ||N d =B% J~K2?" K$ !I$ - ., W% >- (=,2*y!I2 2- $ z~Y 2- $

[$,2b* dE K2* =,2* ,2- .,2 + J2" 2b# @522+1

1 Sigma 2 Merck 3 Steden, Mayer


3

)|YY*B% - (=,2* ,2 S (|~[K2* 2b + k .$W- J" , (T $ "#3$ \W ,2

$ 2- +' $XYYY K2* ~[.,2 2j 2b K5 2N ~/|*B" ,B%$,yJP< - ,&$|YY +,2$

, * , + K5 -2 +'2 O: ,P*3\k ., j $ $ ,W , dP @5 -pH

-y2$ .,2 +, k2 (2T 2* 2- R2: K5$#xY2)$eB ., :-$2F* $2N +2b =$a2 12 .2B[

+b = 4#1B 0N KR2 T* # O* +*MTMS * p - #1B .B[ $N d p ,- ., +-B02N 2

22N L22BW* +22* $ (22T K,22 p22: 4322? 722$,b*yYB* 2S (T - *$5 - $E* p +b =

2N .,2 + J2" 2 #2* $ 2b[ + =,2* - x!I2 Z,22P* ,22 1$22 @22$ #$ 322 .22* 4!<22 yY

B* UB6* K5 >1') +b = 2 2 2 O2?I >2 ., N .! jN =$& B<* 1$2 =-2$ O2*T 2

- O&< * 4K5 6A .* K? =,*zX72 $ !IM: K? $: #- ., p: 3? 2" $2N 4726*

, Ab* @5 7 O&< (Musur & Betondi 2012).

./0% 102 34 56)& "! 7 #8%

3!GCE (* !:; 3!)

$>0"_N 2-#$ "$:2 K,2#2R 2D $ >-% $ .,2 +3 ek 2 2b* $ >YYX/Y% > d 4,YYz/Y 1B d YYz/Y=$a d

$ +b* - , LBW* ;% - K1|*2B2- @5 2% ., S K5- (- +,*5 ! =,*|~zY[d?< $ b

- Bk? +3 - ., +$[ * K,- *K1yY*Dk*% 1) !$#) $2% 2DGCE $2[ 4(

K* =,* ., +YXY[W/ UR2< ,2 + +) b 2 % JBk*% $ !#D2 D ^AO>2 .2

q-#* 0P#.! $[ +3 $*

=# ,- 1* >&7?

2- $F*b* N 4- +b =$a K% !&2=$

D?2) -#2- 4,2 +32 K5 ek2 $2F*% > K, ,- +b =$a K%$ 1B2 ,#

GCE 22D 422 22< U22B6* $ +,22 #|/Y22 $E22*,4|*B +b $E*Y~/Y*B U*2N =2 J

* ., +-#2:; #2N 2-2- O>w/|2|!I2 >D|YY*Bc - !k2 .,2 dP :; !3" , -

D @5 2- +,2 2,2 + 2 +1 .(Chen et al. 2012)

@#700 "! 300;! 7 #800% 004 ,00 300+

/A 3

:; #* !2 2 A: 0-$ - #* 4#.$* +,-$ !) $ $% D ON ,- 4$ > 2

@$) DI !) $ k* *2 .#2:; #2$- 2% !2$ $ $ -$2% >% =2IR !2 23+$2-$

022% 22"#22D? .!22$22b $ >?" Z22/22- KI-W $ -#J2 2"2- 2%#2$2- >

* A*- 4, * $%h?" .$- >=,2 K- (* O) 2 *5 2 !22FBG 2- 2G* K2 $ 2*22 4$ >#

:; # >C* 2>$ 2D?1P 2# A* #- 2* U2 D #2"2A .,2- j2N#2>

+,2 !2 2- +?" $ 22 #2"-$% 4##*2 .22:; $ # +22< 22D K 22 #22"?%,22* =22/4

%5 =/- ?.! +, ()* $ 2>$ 2$2- >U $zYY~ C,2- 2,(Golabi 2005).$*2 $#

D +3 *:D 2D 4$2% 2D 4.2)*

D?%.NO->D $% D $ U?I 2* 2

)K->D $% D D?%+,2 2#2*2 (Bourgeois et al. 2001).

$ 2 >+,2 gR22& 2D J2)$2%(22RN 2D 4>)D?%(O*% D ),"(O2& =2 +'2 2-

,, UB6* ., =J|Y*B 2- 2- 2% $E2*XJ2P< 2- 2- 42- +,2 +,$ D K2I 2 2- !+,26* .,2 +2- $2%

NB-- +, +- $%#<#2- =>Y2y/|s!2 >D !I , F $- --|YY *Bc - !.-


4

Fig. 1. XRD patterns of a) graphene oxide, and b) silver nanoparticles B:DN N #'(XRD) (a ,% > (b 1B +b =$a

CB %4 DE0 04 3! 0(& &0!:;

#7 , 3+

-#$ Kbb6* $$* DB?I D1$j2< =2 @5 *5,b6H +? )* ,, % *K1 j< =2

- !FBG 4= )D KD4=,* K* D12)

D '-$ (Duca et al. 2002) .--!FBG >2"2-b*YY~/Y|Y*B U2B6* $E* =2 2 72

* J#:; #5 $*.!2 $2[ 12h?">$ <#= - -pH -2- !>$*2#2:; 4#

+, #= $ pH 2"#o2nu>D2 !I2 2- nuu *B!$- $*- .! $[ $- $F*$ !?<1* c

+, #*k*5#=4 ,2 +3 =3 =3 D N?K5Â $ " >-% D2 #gR2&

+,22 22*k*5 $ 22-#22$-22.,,22k* +322 22-D?*IR K2"D 2- A-$ $# ,2*)

+ "#- UB6* $5 !2:4K2D U2b 2B?) !2*b*D.ED DÂ2 2- K2D Ub !*b* D.h?" $ >b6 >H-$2F* 2 +,"2*c$ ,2

*N $ >$,#< ,$ D#* 4=#2:; #D Â $ NC/GO-GCE sAg dP.,

.F4 ! G& $ ,2- 2M +322 2-XRD > 22 =632& 22 2)

% $* ,$[! 2- A-$ $ . 2 XRD > 2

%* +, 1 ,% !3 KN 22- =,2 2- E2- $ 22% > 22 22- L22-*< $ ,22ol/noθ=o229 22-#

->E#nl/d'5 N 2- 2S $< $ 2 /oθ=o29 2-#2->E2#on/d2'5 %2< 2%

- $,b* )%, $ % !6* $ +, ,* 74,- 2* +,"* .2 2 >2OD2 $ nsa!2 +,2 + K2

.(Wang et al. 2009, Qin et al. 2012) h?">5N N 1- D $F* % =2/c2'

, dP +b =$a OD)|sb(.b* 2 XRD 2-* 22-22 d22 22- +,22 122 =$a 22% K22 +22b $,22

%* UN .,-"< $2θ2-- z/4XX/X4x/xX4~/yyy/| % , "N >- " 2- L-* (

@22- 22"#) =6322& 22-|||) 4(zYY) 4(zzY) 4 (|| ()zzz* i: +b ( ,- K 2 ,2 +," 2- +2b =$a

$:/q* !.\222 $*#222% > 222 1B222 4+222b =$a222 4,k*%M +3 - !2-$ q qq*n

W) - ., + iOD) - zsa% > (+,2 12 ,$#$:#EE ! ,* 63& 2?% K5 !*W2S

~Y* *2h?" .,2- $:2 >2- 1B2 ,2* 2/ 7* +,z~* OD2) !2 +,"* O-[ OD $zsb.(

M- +2b =$a2 O&< 2=$a 2) ' 2%#OD2$ % !#E- OWBWOD) ," zsc$ .($29< !

"2 2 2 2:22% $ $22$D2,'2-: - -D 'O

1 Scanning Elctron Microscop (SEM)

a b


5

Fig. 2. SEM images of a) grapheme oxide, b) nanocellulose, c) silver nanoparticles, d) graphene oxide/nanocellulose – silver nanoparticle composite, and e) TEM impage of the synthesized silver nanoparticles

B:M SEM a(4,% > (b 41B (c 4+b =$a (d 1B /,% > sb =$a+

(e MTEM +, 1 +b =$a

Fig. 3. a) Cyclic voltammetry of nitrate 10 mM solution in the presence of a 0.2 molar buffer (pH = 4) at the surface of the modified Ag-NC/GO-GCE electrode, and b) unmodified GCE electrode (Scan rate = 100 mV/s)

B:.a(:; #* UB6* #mM|Y - UB6* $9< $ =z/Y) $E*X=pHD ^A $ ( +, gR&NC/GO-GCEs

Ag b(+, gR& DGCE) >D !I .mV/s|YY(

k*%!1)% > OD*+2b =$a2 4, * 1B$ % ,-#- OWBWE- $! OD)zsd.(

BW* $:W1 I- D O5 $ 02$ !#$ K51 P% c 0$1#* K5.

-#NK- - 4+, !W$ 0TN +b =$a* +, 1D DD$/I#n+3,TEM

1 Transmission Electron Microscope (TEM)

"$- >?A*#!2 =$a2 OD2 +,2 >.-2$M TEM =$a +,2 2% K2 +b =$a +, !/c

- +, 1$ $,< $ 1|Y* !OD)zse(.

.#7 , &!:; 3+

+, #*#2D 72 =2NC/GO-GCEsAg 2? d *2 ., dP+ 0.,2 OD2saN22)-

<2#%2,#N $ =2Z,< O|Y/|s) - !22K

a b c

d e

a b


6

,<|Y *k*% D ^A $ k*5D* K $ ," .2 $) >22- K'2<2# H *- KD Ub O

N S O+,2 gR2& d2: 2D - !/ ?%GCE OD)sbk*% 7 ( * !* +,2 2) .,-

%!22Ag 22D $NC/GO-GCEsAg 22* ,2222 >N0-? $M* $ % ,%D ,22<2#NO3

-

7!"#* dP +b U (Bonyani et al. 2016) .&: >% !*) - $!<2* 2- (2 E2- ^A2#

% > 7 +, J" b 41B2 ,22 !2 +, 222 j22c 22221 J22" 22 $ $22 >%D ,2222 (22)**N ) d,I . 2 2% 2 $ 0d *2 !2 - OD

22h?"- >22 ',22 %D22G22 -0"22% $K"#= !(Bonyani et al. 2016).

.D %4pH P5 %pH UB6*D]* "- % ! $2 2#

!6 $ d * ODc* $[ $- 4,"* $ K5#=$S $(Yang et al. 2003).*#:; #+, #

= $pH"#>D2 !I2 - BW*nuu*2B!2$ODX* F<R* O-[,- 2- 2) 2- . 2 26* OD2 >72"#

B[2-2#<2#2* =2? (22 - ,-20"% pH4

Fig. 4. Effect of pH on the cyclic voltammetry of nitrate 10 mM solution using the modified Ag-NC/GO-GCE

electrode at pH values of a) 10, b) 9, c) 8, d) 7, e) 6, f) 5, g) 4, h) 3, and i) 2. (Scan rate = 100 mV/s(

B:=c $-pH :; #* $ #mM|Y 7 =

!k*% DNC/GO-GCE sAg $pH ( - #"ai

(10(a(w)b()c(y)d(x)e(~)f(z)g()h(X)i((.!I)>DmV/s|YY(

Fig. 5. Relationship between pH and absolute value of cathodic current through the Ag-NC/GO-GCE electrode

at a nitrate concentration of 10 mM and a scan rate of 100 mV/s

B:@>- A-$pH D 7 #,% K) HBA* $,[

NC/GO-GCE sAg !FBGmM|Y >D !I = )mV/s|YY(

),% K#1 * 0.,-pH"#zK2- !W - ) - $ U22B6* U22%22>pH22"422-#+,22 22#,22 (22*

- $#N =, %< #$ =pH --Xb- - !/ 4--22- .!22 22>pH 22--X22- K22IpH N2222- #22

$-., F $ " +,2 +$ /* =Eb* $ D5 >?S dP % !6* $ 0% > 7,#- ! -#dP

* (Ghanbari 2013) . OD~212- 2A-$>pH ) 2K,%#* K $) B[ K5 $ % ," 2 2- L2-* K pH 2--X!.

..:% > % D %4

22- 22$- $22F*+,22 4>D22 !I22 22c 22#$ =22!I22 22"#>D22~Y4|YY4|~Y4zYY4z~Y4YY4~Y 4XYY4

X~Y 4~YY ~~Y *Bc - !N % , dP "#-* -2 22 (a22kD $22Ox222 + K22+, .,2 222

*50#" 1 - % K -*=,2 4>D2 !I2 0N,% #1 1* 0h?" .,-1 - >>D2 !I2 04N,% #-ON !? "#3*2 2* !3+,"2* ,2%*T$!IX~Y 2~~Y4N2$2: 2B[ !2< 2"

* - ,,2N $ ,2$ >O2"#E2-4N22" 2&G*2(2,, %2 2B* >2! - d,I +," K jN#

0

20

40

60

80

100

120

140

0 2 4 6 8 10 12

µA

pH


7

Fig. 6. Effects of scan rate on the cyclic voltammetry of nitrate 10 mM using the modified Ag-NC/GO-GCE

electrode in the presence of a 0.2 molar buffer (pH = 4) at scan rates of a) 50, b) 100, c) 150, d) 200, e) 250, f)

300, g) 350, h) 400, i) 450, j) 500, and k) 550 mV/s B:C>D !I c $- :; #* $ #mM|Y =

!k*% D 7NC/GO-GCEsAg - UB6* $9< $z/Y) $E*X=pH ( - >D !I (ak)~Y)a(|YY)b(

|~Y)c (zYY)d (z~Y)e (YY)f (~Y)g (XYY)h (X~Y)i (~YY )j (~~Y)k) ((mV/s(

!2 0% (Thinh et al. 2007). 2 2- $ >2- !I2 >=,"2* 2- )|YY *2Bc 2- !2 2 ,2 2 2F $

.(Yang et al. 2003)

.=>0HI 0D %4 0(() ,0 7 J0K 30

(1%L;*

22- 22$- $22F*!22FBG 22c 22"# 22BW** $ =2222 K1!FBG 4K5 "2b* -YY~/Y2|Y*2B $E2*

UB6* =2.,, 22 7J 1 4>D2 !I2 0N =,,25 #,2% #12 0.!2 )2N K 2 ,2% #

- A: =$&$ -12 >D !I d 0.!2 OD2y* K," T< 0% 2# U2% !26 =2a23 ,2

*,-.*#:; #25 $2*2- 2) 2- .!2 $2[ 1- +,*5 ! $ OD !FBG 0"% - 4N =, 4=

,%#0"% 1! -$#- %#!2FBG - UB6*YY~/Y*2B =,2 $E22*22N >222S ,2 $22P Oq22 >2N222$,#222 k*222% JB222- +,222 1222#222"-$%#

%DD5 5 $ %- ! 2S d,* =$& 2*2 $* K," (Keyvani et al. 2009).

-2 21 !FBG 022=42N =,2% 222,#2 1210

Fig. 7. Diagram of increasing cathodic peak current relative to the square root of the scan rate

B:M1 $?) 0N K,% #$ -!I d

>D

Fig. 8. Effect of nitrate concentration on its cyclic voltammetry by the modified Ag-NC/GO-GCE electrode at nitrate concentrations of a) 0.005, b) 0.01, c) 0.05, d) 0.1, e) 0.5, f) 1, g) 2, h) 3, i) 4, j) 5, k) 6, l) 7, m) 8, n) 9, and O) 10 mM in a 0.2 molar buffer (pH = 4) at a scan

rate of 100 mV/s B:N:; #* $ = !FBG c $- 7 K5 #

!k*% DNC/GO-GCE sAg !FBG - #")YY~/Y)a(Y|/Y)b(Y~/Y)c(|/Y)d(~/Y)e(|)f(z)g(

)h(X)i(~)j(x)k(y)l()m(w)n(|Y)o$$E* B* (( - UB6*z/Y)$E*X=pH) >D !I (mV/s|YY(

* % ,- B* >%D 02% 2,2!D< 7 +, O#D?= !2.(De et al.

2000) 6*%/OD $ Kw2* K2- 2% ,2"!2FBG >

) =,% K#b* A-$'2' J $ 2) 2- - ) (6* >W ,< $,b*+,2 gR2& 2D i* /6*.

y = 0.0034x + 0.0907R² = 0.9949

0.1

0.11

0.12

0.13

0.14

0.15

0.16

0.17

0.18

6 11 16 21 26

mA

V1/2 ((mV/s)1/2)


8

Fig. 9. Calibration curve showing the relationship between nitrate concentration and cathodic current

through the modified Ag-NC/GO-GCE electrode in a 0.2 molar buffer (pH = 4) at a scan rate of 100 mV/s

B:O6*%/K$-) !FBG A-$,% K#

k*% D 7!NC/GO-GCE sAg - UB6* $z/Y)$E*X=pH () >D !ImV/s|YY(

.@>&76* !:; PK2 Q L%

-#W ,< > i*|, +3

)|(m/LOD =3SbD

K5 $ % SbD* 6 4UB6* $blank m 426* (%2/K

*W ,< .,-- i+,*5 !Y|x/Y*/26* $E2* 2D .,

.C>Q' D %4

$>0"_N $ 4=32 =3 !?<1* c#+,2 2#*k*5#$- $* =- % ! $[ 2< - (b

cOD $|Y+,2 + K2 $2F* .,2a OD2 $=2 *- ) - .,- > N 4OD=32 =32 2- L2-*

N 1P* ZR*% K2* $ 2% +2- =2 2"#"2 2 ,)* 25 =,2 2 2- 12?% $ !2 -2- .2$- $ >B:,* = #2? P2P5 .,2%$ 2%~Yc 2 U

=322 =322 22"<22+,22 -22- 4,22>xYc22 U - - (* K* =,* KI#+, #., @W =

Fig. 10. Amperometric response at the surface of the Ag-NC/GO-GCE electrode in the presence of a) nitrate, b)

sulfate, c) phosphate 10 mM in a 0.2 molar buffer solution (pH = 4) and at an applied potential of –1.17 v

relative to SCE B:RD Â $ #*k*5 NNC/GO-GCEsAg $

$9<a= (b=3 (c=3 (mM |Y - UB6* $z/Y)$E*X=pH+, U?I ON (V|/|s- !/SCE

.MS6 %4&!:;

$-2D ,k*?2- * 2A* $2F* 2 !2*b* K1"D Â $ $- Ub#+,2 gR2&GCE 2"D #

k*% +, gR&1) NC/GO-GCE 1) 2 2Ag-

NC/GO-GCE UB6*$|*B$E*K4Fe(CN)6% $kHz |YY OD) ! dP|| .(* K 2- 2) - ,"

$1- A[ J6* $ +DD !GCE 26*)a

OD $||sa* 4() $- Ub K1Rct !/ - (02W- +- *"*6*1 $,b50 $ 2D 2% !2 2 !2<

K: +,+% $: U5 .! < $ Â2 $ !2*b* 2%1) +, gR& DNC/GO-GCE 0"%#!/2

-GCE 6*) ! b4(2 $2 +,2 gR2& 2D221)Ag-NC/GO-GCE 226*)c22* +,"22* 4( 22% 2222 >

$ D#?%*2"* 02W- $,b* >* +2- 2 K1Rct - !/1) +, gR& +, gR& D$,2b* - 4

J; #0"%U,2)) !2 |J2$ 2- ,2- 2B<* $ .(6*"#D2* ! $ K5 O2&< U2* $,2* K2 2 1

OD22) 22? J22$||sb (22 U22b !I22 !22-c K5 H" KD#)kapp $ ( +3 - 1* z? /6*

)z(K=RT/F2RctC

y = 0.0051x + 0.0792R² = 0.9992

0.07

0.08

0.09

0.1

0.11

0.12

0.13

0.14

0 2 4 6 8 10 12C/mM

I/mA


9

Fig. 11. A) Nayquist curves of: a) unmodified GCE electrode, B) modified two-part NC/GO-GCE electrode, and c) modified three-part Ag-NC/GO-GCE electrode, B) Equivalent circuit resulting from the Nayquist curve.

B:(A ) !D #" 6*a+, gR& D (GCE) 4b1) +, gR& D (NC/GO-GCE ) c!k*% D (

1) +, gR&NC/GO-GCE sAg.b) !D 6* O&< U* $,* (

$4A-$ >R-22" !I2 !2-c ' )J/molk|X/4(T

22*# H22BA*) J22kzw 4(F$22 !22-c +,22" K22#)C/molwxX~ (C>22"5 U22B6* !22FBG!22.(Sun et al.

2011) 22U,22) $ $,22* |22* K224,22" kapp 22D $

NC/GO-GCEsAg b* $2"D 2- #GCE NC/GO-

GCE E- $,b* #$$:-4! j%D ,2<#K"# ^A $ ='< >OD -

'?;#O E- !I -* dP .

.N#7 Q 3;! "! 4 , 3+

+, # K* $ +3 - =#$$; 2?b<b,* @5)2 @5 K$2- @5 4+2; @5 4#,2 d2P (

U,))z(.K?" % $* K D ,"- $%j* -:+,2 2- $2[ E2- $ !2[ - 2#=2 2: ^A2 $

*.,-

T!U?D ,k* NDDk $- $ "*$N b* Table 1. Values the parameters used in EIS investigations

Electrode )Ωk(Rs )cmµF/2 (CPE )Ωk(Rct Zw Kapp

GCE 4.541750 1.635610 2.758980 1.128290 9 ∗ 10NC/GO-GCE 3.627930 1.999999 1.502096 1.78450 1.7 ∗ 10

NC/GO-GCE -Ag 1.784060 9.946780 1.256890 1.029400 2.11 ∗ 10

T!U+, ? $ = # / #" Table 2. Measured values of nitrate concentration in natural samples

Accuracy(%)

RSD(%)

Nitrate Concentration)(Proposed Method

ppm

RSD(%)

Nitrate Concentration(Spectrophotometry)

ppm

Samples

102.4 3.92 523.0 3.84 510.3 Water well 102.2 3.87 436.4 3.81 426.9 Rain's water 97.6 2.11 25.3 4.12 25.9 Mineral water 99.4 2.65 37.9 3.69 38.1 Urban water

B

A


10

Fig. 12. Diagram of reducing current peaks of the cyclic voltamograms for the modified Ag-NC/GO-GCE

electrode in a nitrate 10 mM solution at a scan rate of 100 mV/s after 5 days

B: B[ K) 0"% $?"% # :; d *

+, gR& DNC/GO-GCE sAg = UB6* $mMnu - UB6* $9< $z/Y$E*t=pH>D !I)mV/s|YY(

!j ,-m$

.O !:; , 7 3&?GCEsGO/NCsAg

- $F* +,"*c* $ , N $ >$,#,2$ 2D<#* 4=#2:; #+,2 gR2& 2D Â2 $

6* ! dP)J2$ $ ,2 - !/ K 2 ,)OD2|z(.* K;2 0"% % ,"1#) $ 2 * 2- K 2 K1

,22&$ 22% $ 22)2222* $D225 C22S* >22D 22% ,22%NC/GO-GCE sAg 22 +322 22N +,22 ~K22h?" $

N ,- +- $,%$% - $ , >z I,P - 2 , / .$ D Â $ ,P* ek 2- K K2 $2F*

* 0"%) =,2 K1 2 2b* 4K) 22- K HBA*$,2[ =$2&.! +, +$5

= 3+ $2222- +\22N >#22$22- >'22<NC/GO-GCEsAg

- $F* +, #*# K * =Â gR& .,D >-%#-k*% ?%- !N2% > ,

- _"# - M6* 2$ E2- Â2 !<2* F % 2 1B2 +2?" 2- E-4+,2 2N +2b =$a !2

$22%022% d22P 22"#22D?22% =$,22[$1# - $ DP1 J" c -'?2; $2#2- $2F*

+, 2#2 K=2 12 . 02,2k* DNC/GO-GCEsAg 2 * '< % K+,24

?% $- Ub !*b*#+,2 gR2& 2D 2- !/2GCE j 4$%D ,<#K2"#Â2 $ =2

DOD - 2F<R* O-[ #22* O.2 2- e b6 >* H2- K $2%#'2< NC/GO-

GCEsAg+, !) $ # K=2 2< 2-!2[ !N E-$,#? $ (* "#-5 BW*N.?

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0 1 2 3 4 5 6

Cur

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