Design, development and characterization of graphene sand Nano-composite water filter

Shahid Hussain Abro1 Thouth Sung woan2 (타성원)

Department of Materials Engineering NED University of Engineering and Technology (Pakistan)

Email: engrabro@neduet.edu.pk

Abstract

Water purification and filtration is a global issue and many researchers are engaged to resolve

this problem, connecting to this major issue a scientific approach will be adopted in the present

research work, graphene sand composite will be prepared through biosynthesized technique by

means of anchoring of sugar particles upon the particles of sand from sugar anchoring on sand

particles except using the binder, this will develop a composite that can be cited as graphene

sand composite (GSC), that will be employed in water filtration. River sand will be used in this

context, to remove the impurities already present in the sand particles; nitric acid will be to treat

the sand. After treating the sand in 0.1M nitric acid, deionized water will be used to wash the

treated sand and drying of the wet sand at around 100±3°C. After drying twenty gram of sand

will be mixed in 1M sugar suspension, to dissolve both solutions, the mixture will be stirred on

magnetic hot plate for five hours at 86oC and then dried. This prepared mixture will be place in a

ceramic crucible having activated charcoal and will be heat treated for 360 minutes in a muffle

furnace. The product after heat treatment will be in the form of a powder that can be by

concentrated sulfuric acid for sufficient time and the powder will be washed using deionized

H2O. To remove the moisture content the washed powder may then be dried on hot at 120oC the

product then can be obtained a powder black in color, referred as GSC, graphene sand

composite.

Key Words: Graphene, biosynthesized, sugar anchoring, sand particles, water filtration.

Introduction: and Literature review

Drinking water purity and refining has been a hot issue nowadays. Water is a basic need for

living things especially for human beings. A scientific approach is made in this work to design

and establish the unique method using advanced and traditional method to purify the drinking

water. Graphene is a exceptional 2-dimensional allotrope of carbon [1-2]. It gains attentions by

many researchers around the globe due to its extraordinary structure and physicochemical

characteristics. Many research scientists have conducted investigation on grapheme, modified

form of graphene, graphene/metal nanoparticle composites, graphene hybrids as well as

graphene- oxide composites. The applications of graphene along with graphene based

compounds/composites for the removal of pollutant, filtration, environmental remediation,

electronic circuits, solar cells and several chemical, industrial and medical processes are being

explored. Graphene can be prepared by two distinct methods I) Graphite is chemically

transformed to GO, graphite oxide followed by reducing the graphite oxide by N2H4 (hydrazine)

to reduced grpahene oxide II) Anchoring of graphite oxide and reduced graphite oxide upon sand

particles either by applying heat treatment or by covalently bonding on silica directly as well as

by applying molecular binders. Although many different chemical can also be used to synthesize

of RGO such as N2H4 (hydrazine), (P2O5) and (K2S2O8) as a result it can generate unwanted

hazardous products such as, (P2O3), (SO2), etc. This may require laborious work such as post-

synthesis cleaning. It is most desirable to develop and produce the graphenic adsorbent in

economically way as well as it must be echo-friendly used for water purification and filtration

[3-5]. Many graphene based composites have been developed so far even with and without metal

oxides for water filtration applications but being success of any such materials, cost is always the

main criterion, and therefore it becomes compulsory that new and advanced prospective

techniques should always be used for producing such products [5-8]. Graphene sand composite is

the in situ development of graphenic stuff material supported upon the surface of river’s sand

which requires additional binders. But in this research process no harmful residues are left when

sugars readily decompose into carbon. Waste water can be treated by bio synthesized grapheme

process imposing the anchoring of graphene upon the river’s sand can make unlikely to change

the graphene as a result by farming it more suitable for treatment of flowing water framework

[9-10]. The method used in this research work for synthesis of our composite is different from

conventional composite manufacturing, because it is a nanocomposite. The solution of sugar and

river sand is prepared with appropriate ratio. This solution is then heated and mixed with

magnetic stirrer to evaporate the water and a solid mass of sugar and sand mixture is obtained. It

is then placed in the muffle furnace and heat treated [11]. After removing from furnace it is

treated with sulfuric acid to activate it. The different characterizations techniques used for the

identification formation of graphene sand composite are SEM imaging, XRD analysis and FTIR

spectroscopy. Adsorption test and Water drinkability test are performed as Water filtration tests.

Materials and Experimental work

Materials used in the process were almost all easily available and purchased from the local

suppliers. Sugar, sulfuric acid, nitric acid, activated charcoal and deionized water. The sand was

obtained from the sea view, having the particle size of 180 microns; some of this sand was

grounded to fine particle size of 3 microns. The overall experimental work was performed in the

following steps:

Step 1. a) Synthesis of GSC. Sand was first washed with 0.1M nitric acid in order to remove

any contaminants present in the sand. These contaminants could be different ions causing any

unfavorable reaction during the process. Then this sand was dried subsequently in air for one

day. This washed sand was used in all the experimental iterations, performed as shown in Fig 1

A.

Fig.1 A) washing sand with 0.1 molar nitric acid. B) weighing of 20gm of sand. C) preparation

of 1M sugar solution and and sand mixture.

b) Preparation of sugar sand solution. 1Molar sugar solution was prepared by adding 342

grams of sugar in 1Litre of deionized water. This was done by mixing the solution thoroughly.

Then 20 grams of sand (particle size 180micron) was added to the solution by weighing it on

weight machine. As has been shown in Fig 1B and 1C.

A B C

Step 2. Mixing and drying on magnetic stirrer a) The beaker containing the solution of sugar

and sand was placed on the hot plate magnetic stirrer for about 6 hours for continuous stirring

around 85oC to evaporate the water. The sample was ready indicating the grey color of the

solution as shown in Fig. 1.7

Fig.2A sample obtained after hot plate stirring. Fig.2B cruicible covered with charcoal. The

dried sample was put inside of the graphite crucible.

The crucible was under cover by activated charcoal dispersed from all sides to provide for the

reducing environment as shown Fig 1B. Heat treatment was performed in a muffle furnace.

Fig.2C heat treatment cycle for GSC sample, first it was heated to about 2000C in 1 hour then it

was held there for about 1 hour to uniformly heat all the sample, heated to 7500 C in 1 hour and

held at this temperature for about 3 hours and then furnace cooled. After heat treatment, black

sample was obtained which was graphene sand composite as shown in fig. 2.4.

Fig.2.4 GSC powder after heat treatment. Fig.2.5 Filtering sample after Fig.2.6 drying the

sample on hot plate at 1200C treating with sulfuric acid.

A B C

The sample obtained from the furnace was treated with sulfuric acid; for every 5gm of sample

20ml of acid was used; for about 1 hour to active it and then washed with deionized water after

which it was filtered by means of filter paper along with funnel assembly. The resulting sample

was then after dried on the hot plate for about half hour at 1200C as shown in fig. 2.5 and 2.6.

Step 3 Now again followed same methodology but in this iteration the particle size of sand was

reduced from 180 microns to 3 microns. This was achieved through ball milling of the sample

for about 75 hours. The sample obtained from ball milling machine was very fine powder of

white color as shown in Fig. 3.1 and 3.4

Fig 3.1 Ball milling machine Fig.3.2 White Powder of 75 hrs. Ball Milling Sand. Fig.3.3 GSC

obtained after treatment.

The sample obtained after magnetic stirring, heat treatment process and washed with sulphuric

acid was of whitish brown color.

Step 4 water Filtration. A simple filter was made by taking a glass tube open at both the ends.

The tube was closed at one end which will allow only water to pass through the sample and also

hold the sample in place as shown in Fig.4.1

.

Fig.4.1 Filter Design with simple tube covered at one end with cloth. Fig 4.2 dirty water from

mud. The water from the mud was collected in a beaker and passed through the filter tube and

collected in the bottles for further testing of this purified water as shown in Fig.4.1

Results and discussion

(1) Synthesis and characterization of GSC

a) X-ray Diffraction

The XRD result of the GSC sample in the powdered form (180 micron) is shown in Fig 5.1. The

peak obtained at 20.93 degrees represents the multilayered graphene structures which are formed

by the treatment of the composite with acid and application of the high temperature in the

procedure. The d-spacing for GSC is also higher, from pristine graphene because of this

treatment, and equals to 0.42 nm. The characteristic peaks of graphene are obtained at 26.69,

42.46, 44.7, 54.82 degrees.

Compared to the results obtained from the articles shown in figure 4.2, the peak for multi layered

graphene is obtained at 20.97 degrees and the corresponding d-spacing is 0.402 nm. As from the

article, the characteristic peaks of graphene are obtained at 26.73, 42.541, 45.875, 54.959 and

64.11 degrees.Almost similar results were obtained when the sand size was reduced to 3 microns

by ball milling for 60 hours. Here, the peaks are obtained at 26.56, 42.40, 44.53, 52.51 degrees,

as shown in figure 6.3.

Fig.5.1 XRD Pattern for 180 micron GSC. Fig.5.2 FTIR of GSC sample

b) FT-IR SPECTROSCOPY

The FTIR results as shown in fig 5.2 verify the proper and perfect graphitization of 180-micron

sand. Look at the GSC spectrum, clearly indicate the absorption band on 1/1631.5 cm, that has

close similarity straighten at C=C point, that indicates the sketchy grapheme structure. An

absorption band straighten at 1/1095.1 cm indicates the C=O sketchy grapheme structure.

However, the band straighten at 1/3415.5 cm indicates O-H, which represents the oxygen

functionality is present at that point. The spectrum at 1/2925cm is C-H and at 1/778 is C-H.

3. Results of filtration

(1) UV visible spectroscopy

The Fig. 5.3 and 5.4 below communicate an elementary UV-visible absorption spectrum for mud

water and filtered mud water sample. The values on y-axis indicate the amount of light absorbed.

If the Y-axis value is greater the higher the wavelength is being absorbed. The huge difference

was obtained between absorption of mud and filtered mud water.

Fig. 5.3 UV-visible absorption spectrum for mud water and Fig. 5.4 UV-visible absorption

spectrum for filtered mud water.

Acknowledgement

Authors are great fully to NED university of Engineering and Technology and Korea Advanced

Institute of Science and Technology for their support and help to complete this research work.

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