1. A defluoridation filter media comprising: a) Atleast a bottom composite layer comprising polyvinyl alcohol-cellulose acetate-AI2O3 nanoparticle- coconut carbon shell composite; b) Atleast a top composite layer comprising Cellulose acetate-graphene oxide- AI2O3 nanoparticle composite; c) Atleast a middle composite layer comprising AI2O3 nanoparticle - polyurethane foam composite.

2. The filter media as claimed in claim 1, comprising said top composite layer, middle composite layer and bottom composite layer is present in a ratio of 50:40:10.

3. The filter media as claimed in claim 1, wherein said AI2O3 nanoparticle is synthesized through green method from jojoba leaf.

4. The filter media as claimed in claim 2, wherein said AI2O3 nanoparticle is synthesized by following steps: a) adding aluminum nitrate to jojoba leaf extract in approximately 1:3 ratio (w/w) followed by constant stirring at room temperature to obtain a mixture; b) microwave heating the mixture resulting from step (a) for approximately 7 minutes, to obtain a yellow brown precipitate; c) centrifuging the precipitate resulting from the step (b) followed by washing by methanol and drying to obtain said AI2O3 nanoparticle.

5. The filter media as claimed in claim 1, wherein said Cellulose acetate-graphene oxide- AI2O3 nanoparticle composite is prepared by the steps of: a) preparing 1 g cellulose acetate solution by mixing in approximately 20 ml acetone; b) adding approximately 1 g AI2O3 nanoparticle and approximately 10 mg graphene oxide to the solution resulting from step (a) followed by stirring to obtain a suspension; c) Sonicating the suspension obtained from the above step to obtain said Cellulose acetate-graphene oxide- AI2O3 nanoparticle composite.

6. The filter media as claimed in claim 1, wherein said AI2O3 nanoparticle - polyurethane foam composite is prepared by the steps of: a) Suspending AI2O3 nanoparticle in approximately 100 ml of distilled water for sonication b) Impregnating AI2O3 nanoparticle resulting from step (a) on the polyurethane foam through dip adsorption method to obtain the composite.

7. The filter media as claimed in claim 1, wherein said polyvinyl alcohol-cellulose acetate-AI2O3 nanoparticle- coconut shell composite is prepared by following method: a) Washing, drying and crushing the coconut shell to uniform powder followed by adding potassium hydroxide to the powdered coconut shell matter; b) Heating the coconut shell powder resulting from step (a) at approximately 800°C for 2 hours; c) Rinsing the activated carbons obtained from step (b) followed by drying; d) Dissolving approximately 1 g of coconut shell powder in approximately 50 ml AI2O3 nanoparticle solution of 1 g concentration to obtain a solution; e) Treating the solution resulting from step (d) in vacuum oven at approximately 110°C for about 2 h for full coating of AI2O3 nanoparticle onto the coconut shell powder; f) Preparing a second solution by adding approximately 8g polyvinyl alcohol powder in approximately 100ml water to obtain a suspension followed by adding the glutaraldehyde solution and cellulose acetate; g) Adding the solution resulting from step (e) with the second solution resulting from step (f) to obtain said polyvinyl alcohol-cellulose acetate-A^Ch nanoparticle-coconut shell composite.

Field of the Invention:
The present invention relates to the Fluoride (F) remediation of water samples. The Invention in particular provides composite/s and filter media comprising the composite/s, useful for the removal of fluoride content from a water sample.
Background of the Invention:
The following background discussion includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Fluoride (F) is a major contributor to the world water crisis, affecting about 200 million people worldwide (WHO, 2015; Khairnar et ah, 2015). It is reported that around 24 countries are severely affected by high F concentration in drinking water (Khairnar et ah, 2015). The rural population is more prone to F contamination as in some places, the available techniques are neither acquainted nor affordable. The fluorosis is reported more prevalent in rural population due to excess F contaminated water inevitably consumed by the rural population (Almas et ah, 1999; Rashmi et ah, 2013). F is known to cause mottled enamel, osteoporosis, crippling skeletal fluorosis, thyroid imbalance, growth retardation, kidney imbalance, types of morbidity and in severe cases leading to mortality (Ozsvath, 2006). Several methods have been developed to efficiently remove F from water, including nanofiltration, reverse osmosis (RO), coagulation, electrocoagulation, electrochemical oxidation, ion exchange and adsorption (Raghu et ah, 2009; Bejaoui et ah, 2011; Gwala et ah, 2011; Gong et ah, 2012).
Till date, the defluorinated water at the community level in the outreach areas is far away due to its high cost and complex treatment modalities. After water, tea infusions are the most popular beverages consumed worldwide by communities (Graham, 1992). It is well-known that tea plants can accumulate F, for example, in 1930 it is reported that Camellia sinensis (tea plant) is a hyperaccumulator plant of F (TOKALIOGLU et ah, 2004). F concentrations above permissible limit were reported in tea drinks of India (1.55-3.21 mg L"1), China (1.60-7.34 mg L"1), Kenya and Tibet (2.59 mg L"1) (Gulati et ah, 1993; Cao et ah, 1996; Fung et ah, 1999). The cost and effectiveness of the defluoridation techniques are still not satisfactory and thus requires further improvements. The existing defluoridation technologies suffers with

the drawbacks in terms of high cost, low durability, non-reusability and Low water
purification capacity.
The available methods for F removal are:
1. Reverse Osmosis (RO)
2. Forward Osmosis (FO)
3. Evaporation
4. Ion-exchange
5. Precipitation
6. Adsorption
Among the reported techniques, adsorption is considered more advantageous for the rural population as it is inexpensive, rapid, easy to operate and highly efficient (Jagtap et ah, 2012). Several traditional adsorbents were reported such as activated carbon, zeolites and bone char but nanostructural materials proved highly efficient for F removal because of their high surface-to-volume ratio (Wang & Peng, 2010; Cai et ah, 2013; Gupta et ah, 2015). The limitations of existing defluoridation technologies are:
1. Ion-exchange: Synthetic chemicals, namely, cation and anion exchange resins have been used for F removal from water. A strongly fundamental anion-exchange resin can be used for F removal containing quaternary ammonium functional groups. Limitations: Contamination prone, expensive, water wastage is high, large volume regenerate required for cation and anion exchange resins regeneration.
2. Membrane process: In this process, on the basis of molecular shape and size, particles are isolated using extraordinarily composed semi-permeable membrane. The common membrane processes for F removal are reverse osmosis (RO), nano-filtration, electrodialysis.
Limitations: Expensive, large amount of water is rejected as brine, high electricity consumption and removes all ions including essential minerals, water membrane cost
is high, fouling of membrane takes place, membrane has to be changed periodically.
3. Precipitation: This method involves the precipitation of sparingly soluble F salt as
insoluble fluorapatite by the addition of chemicals (coagulants and coagulant aids).
Most common materials used in the technique are Aluminium salts (e.g. Alum), lime
and Poly Aluminium Hydroxy sulphate. It involves addition of Aluminium salts, lime
and bleaching powder followed by rapid mixing, flocculation, sedimentation,
filtration and disinfection.

Limitations: Required dosages of chemical are high, requirement of trained labor, sludge produced after treatment is high, high concentration of aluminium is released in water during process which may cause Alzheimer's syndrome. The cost and effectiveness of the F removal techniques are still not satisfactory.
Hence, there is needed a durable defluoridation technologies which is cost effective and highly efficient in terms of purification capacity.
The Invention provides a highly efficient and cost effective defluoridation filter media with high Fluoride removal capacity, durability, reusability, ease of operation, portability, environmental friendliness.
Object(s) of the Invention:
A primary object of the present invention is to overcome the drawback/s associated with the
prior art.
Yet another object of the present invention is to provide green and cost-effective solution for
the defluoridation of water.
Yet another object of the present invention is to provide polymeric composite/s for
defluoridation of water.
Yet another object of the present invention is to provide a defluoridation filter media based
on AI2O3 nanoparticle composites.
Yet another object of the present invention is to provide green synthesis of AI2O3
nanoparticles.
Yet another object of the present invention is to provide composite based on polyvinyl
alcohol-cellulose acetate-AI2O3 nanoparticle- coconut carbon shell.
Yet another object of the present invention is to provide composite based on Cellulose
acetate-graphene oxide- AI2O3 nanoparticle.
Yet another object of the present invention is to provide composite based on AI2O3
nanoparticle - polyurethane foam.
Yet another object of the present invention is to provide a defluoridation filter media which
prevents leaching of the nanoparticles, useful for the defluoridation of water.
Yet another object of the present invention is to provide a defluoridation filter media with
enhanced durability, useful for the defluoridation of water.

Yet another object of the present invention is to provide a defluoridation filter media that can
be reused in the process of defluoridation of water.
Yet another object of the present invention is to provide a defluoridation filter media with
enhanced purification capacity.
Yet another object of the present invention is to provide a process of defluoridation of water
using the defluoridation filter media as described above.
Brief Description of the Drawings:
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings in which:
Figure 1: illustrates filter media with three composites filled in tube.
Figure 2: illustrates (a) FESEM of A1203 NPs, (b) EDX spectrum A1203 NPs, (c) FESEM of graphene oxide and (d) EDX spectrum of graphene oxide.
Figure 3: illustrates XRD profile of AI2O3 nanoparticles
Figure 4: illustrates effect of time on F removal % (pH: 6 and F concentration: 2 mg L"1).
Detailed Description:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof. Throughout the patent specification, a convention employed is that in the appended drawings, like numerals denote like components.
The present invention relates to the Fluoride (F) remediation of water samples by providing a product and process based on the same for remediation of Fluoride.
The Invention provides a green and cost-effective product based on nanoparticles (NPs) for removal of fluoride content from a water sample.
The present invention provides a cost-effective, durable, reusable, portable, environment and user-friendly defluoridation filter media.
In an embodiment, the defluoridation filter media is based on AI2O3 nanoparticle synthesized through green process using jojoba (Simmondsia chinensis) leaves.
In an embodiment, the AI2O3 nanoparticle were utilized for synthesis of filter composites.
In an embodiment, the filter composite comprises Cellulose acetate-graphene oxide- AI2O3
nanoparticle composite.
In an embodiment, the filter composite comprises AI2O3 nanoparticle -Polyurethane Foam
(PUF).
In an embodiment, the filter composite comprises PVA-Cellulose acetate- AI2O3
nanoparticle- coconut carbon shell composite.
In an embodiment, the defluoridation filter media comprises following components:
a) Atleast a bottom composite layer comprising polyvinyl alcohol-cellulose acetate-AI2O3 nanoparticle- coconut carbon shell composite;
b) Atleast a top composite layer comprising Cellulose acetate-graphene oxide- AI2O3 nanoparticle composite;
c) Atleast a middle composite layer comprising AI2O3 nanoparticle - polyurethane foam composite.
In an embodiment, AI2O3 nanoparticle is synthesized by following steps:

a) adding aluminum nitrate to jojoba leaf extract in approximately 1:3 ratio (w/w) followed by constant stirring at room temperature to obtain a mixture;
b) microwave heating the mixture resulting from step (a) for approximately 7 minutes, to obtain a yellow brown precipitate;
c) centrifuging the precipitate resulting from the step (b) followed by washing by methanol and drying to obtain said AI2O3 nanoparticle.
In an embodiment, the Cellulose acetate-graphene oxide- AI2O3 nanoparticle composite is prepared by the steps of:
a) preparing 1 g cellulose acetate solution by mixing in approximately 20 ml
acetone;
b) adding approximately 1 g AI2O3 nanoparticle and approximately 10 mg graphene
oxide to the solution resulting from step (a) followed by stirring to obtain a
suspension;
c) Sonicating the suspension obtained from the above step to obtain said Cellulose
acetate-graphene oxide- AI2O3 nanoparticle composite.
In an embodiment, AI2O3 nanoparticle - polyurethane foam composite is prepared by following steps:
a) Suspending AI2O3 nanoparticle in approximately 100 ml of distilled water for sonication
b) Impregnating AI2O3 nanoparticle resulting from step (a) on the polyurethane foam through dip adsorption method to obtain the composite.
In an embodiment, the polyvinyl alcohol-cellulose acetate-Al203 nanoparticle- coconut shell composite is prepared by following method:
a) Washing, drying and crushing the coconut shell to uniform powder followed by adding potassium hydroxide to the powdered coconut shell matter;
b) Heating the coconut shell powder resulting from step (a) at approximately 800°C for 2 hours;
c) Rinsing the activated carbons obtained from step (b) followed by drying;
d) Dissolving approximately 1 g of coconut shell powder in approximately 50 ml AI2O3 nanoparticle solution of 1 g concentration to obtain a solution;

e) Treating the solution resulting from step (d) in vacuum oven at approximately 110°C for about 2 h for full coating of AI2O3 nanoparticle onto the coconut shell powder;
f) Preparing a second solution by adding approximately 8g polyvinyl alcohol powder in approximately 100ml water to obtain a suspension followed by adding the glutaraldehyde solution and cellulose acetate;
g) Adding the solution resulting from step (e) with the second solution resulting from step (f) to obtain said polyvinyl alcohol-cellulose acetate-Al203 nanoparticle-coconut shell composite.
In an embodiment, the top composite layer, middle composite layer and bottom composite layer is present in a ratio of 50:40:10.
Preparation of Simmondsia chinensis (jojoba) leaves extract:
In an embodiment, Jojoba was selected for green synthesis of Al NPs as are inedible due to presence of antinutritional factors (simmondsin) and cost effective. For this, the leaves were oven dried at 60 °C for 1 h and ground in a grinder. Next, 10 g of leaves powder was added into 100 ml deionized water and boiled at 80 °C for 25 min. After cooling, the suspension obtained was filtered using Whatman's No.l filter paper and stored at 4°C. The filtrate was further utilized as reducing and stabilizing agent for NPs synthesis.
AhOjjNPs synthesis:
In an embodiment, for AI2O3 nanoparticles (NPs) synthesis, aluminum nitrate (A1(NC>3)3) was added into leaves extract with 1:3 ratio (w/w) and allowed constant stirring at room temperature. The mixture obtained was microwave heated at 540 W for 7 min, which yield a yellow brown precipitate that was later centrifuged. The precipitate was washed with millipore water followed by methanol and dried at 100 °C in oven.
Characterization of NPs
The surface structure of A1203 NPs was observed by FESEM (MIRA3 TESCAN). The elemental composition of NPs was identified by EDX analysis.
Composite 1/ Top composite layer:

Cellulose acetate-graphene oxide- AI2O3 NPs composite:
In an embodiment, AI2O3 NPs were synthesized through green method using jojoba leaves, as described above, and graphene oxide was synthesized though modified Hummers's method. For this, 1 g cellulose acetate solution was prepared in 20 ml acetone through vigorous stirring at room temperature. Further, 1 g AI2O3 NPs and 10 mg graphene oxide was added at room temperature with stirring. Suspension obtained was sonicated for perfect mixing. Thus obtained product was dried at 80 °C in an oven and further utilized.
Composite 2/ Middle composite layer AhOa NPs- PUF:
In an embodiment, AI2O3 NPs were synthesized through green method using jojoba leaves as described above. The impregnation of AI2O3 NPs onto the PUF was performed through dip adsorption method. The NPs were suspended in 100 ml of distilled water for sonication. Then PUF were cut into a size of 4 x 4 cm with 3 mm thickness for impregnation process. For impregnation, 4 x 4 cm size PUF was placed in 0.3 g NPs solution subjected to constant stirring at 200 rpm for 24 h at 30 °C in a shaker. Finally, the resulting NPs-PUF product was repeatedly washed with distilled water twice to remove un-anchored NPs on PUF. Thus obtained product (NPs-PUF) was dried at 80 °C in an oven.
Composite 3/ Bottom composite layer: PVA-cellulose acetate-AI2O3 NPs-CCS composite:
In an embodiment, AI2O3 NPs utilized for PVA-cellulose acetate-A^Ch NPs-CCS polymeric composite development were synthesized from jojoba seed shell extract as described above. Firstly, coconut shell was washed with distilled water to remove inorganic and organic impurities, dried at 105°C for 24 h, then crushed and sieved to obtain a uniform size. In the process, potassium hydroxide acts as an activating agent which is mixed with the obtained powdered coconut shell matter. After pretreatment, the samples were heated in a furnace up to 800°C for 2 h. Further, the obtained activated carbons were rinsed repeatedly with hot and cold distilled water. The obtained CCS powder was dried in hot air oven and used further. Further, 1 g of CCS powder was dissolved with 50 ml AI2O3 NPs solution of 1 g concentration under vigorous stirring at room temperature overnight. The obtained mixture was then cured in a vacuum oven at 110°C for about 2 h to allow full coating of Al NPs onto the CCS powder.

Further, PVA-cellulose acetate-Al203 NPs-CCS composite was prepared through traditional method with slight modifications. 8 g of PVA powder was suspended in 100 ml millipore water with steady stirring for 8 h at 80°C. After PVA was fully suspended, glutaraldehyde (GA) solution (0.8 wt%) was mixed into the above suspension and dissolved after mixing at 60°C for about 4 h, followed by addition of 0.5 g CA and the above prepared Metal-CCS solutions. The final composite was dried in oven at 80°C for further application.
The Filter media of the present Invention removes approximately 97.5% fluoride in a sample.
In an embodiment, the filter media is designed in the form of tube. However, media may be designed in other forms as well.
In an embodiment, the filter media showed negligible leaching of nanomaterials. The product
also showed durability after F adsorption from drinking water and can be reused for the
defluoridation of the water samples. The Invention thus provides an affordable solution for
Fluoride removal for rural and poor population for health and safety.
The below table shows comparison of the filter media of present Invention and the existing
technologies:

The defluoridation filter media of the present Invention comprises following advantages:
a. The product prevents leaching of the nanoparticles. The nanoparticles have compact
arrangement with chemicals and are adsorbed on suitable polymers.
b. The durability of the product is enhanced. This is due to the chemical components
being used in the product
c. The product can be reusability
d. Water purification capacity is enhanced. Fluoride adsorption will be enhanced and
checked through increased surface area and NPs.
e. Highly cost effective
f Eco-friendly
g. User friendly
h. No energy requirement
i. No water wastage
The Invention is further described with the help of non-limiting examples: Example 1:
The filter media is based on atleast three composite/s. The details are mentioned below: Three composites filled in tube as: Cellulose acetate-graphene oxide- AI2O3 NPs composite, AI2O3 NPs-Polyurethane Foam (PUF) and PVA-Cellulose acetate- A1203 NPs -CCS composite are utilized for F remediation.
Example 2:
All three composites were filled in tube for further adsorption studies. Lower part is filled with PVA-cellulose acetate-A1203 NPs-CCS composite, middle layer is A1203 NPs- PUF and

upper layer is Cellulose acetate-graphene oxide- AI2O3 NPs composite (FIG. 1). The product was utilised for defluoridation studies.
Example 3: Adsorption experiments
The adsorption studies were conducted using different F concentrations, such as 2, 4, 6, 8 and 10 mg L"1 with 500 ml solution and with different adsorbent content. The contact period was varied to 20, 40, 60 and 80 min and the flasks were placed in shaker at 140 rpm. Effect of pH on the F adsorption was calculated in pH range of 2-9. Finally, the remaining F concentration was detected by F ion meter. The removal efficiency of the adsorbent was detected as: Removal efficiency (%) = C0-Ce/ C0 x 100
Example 4:
Morphology and chemical composition
FESEM images of AI2O3 NPs showed the irregular shape of NPs is shown in FIG. 2a. The Al and Oxygen (O) peak in EDX spectrum showed AlO presence in the sample (FIG. 2b). The FESEM image shows that few layered graphene oxides are formed (FIG. 2c). EDX showed the variation of relative ratio of each element in graphene oxide sample (FIG. 2d).The XRD patterns of AI2O3 NPs are shown in FIG.3. For the AI2O3 NPs, intense diffraction peaks at 66.72°, 45.46° and 36.82° were observed, which corresponded to the planes (240), (-422) and (221), respectively. The XRD patterns declared the monoclinic crystal phase of AI2O3 NPs (00-011-0517).
Example 5:
Effect of pH and Contact time
The composite filled tube is utilized for F adsorption. The pH of the solution is an important factor in the F remediation for the batch studies. The surface charge of the mineral oxides is positive when pH value is below pH zero point charges (ZPC) and negatively charged when pH value is above the ZPC. The removal of F through developed product was considered to be mostly pH dependant. The F remediation percentage enhanced with increasing pH up to 6. However, removal percentage for F reduced as the pH increased above 6.0. Under alkaline environment, F removal reduced due to the competition between F ions and hydroxyl ions for the active surface sites. In acidic pH environment, the formation of hydrofluoric acid is

accountable for the decrease of F adsorption. The results confirmed the decline in F removal upon increasing the pH above 6. Adsorption performance was considered as a function of contact period from 20 to 80 min with the developed product at pH 6 at 30°C. It is understandable from the mentioned results that F adsorption increases with time period and an equilibrium state is achieved after a contact time of 80 min.
Example 6:
Effect of initial fluoride concentration
The results illustrate that F ion adsorption decreased with enhanced initial F concentration (FIG. 4). The F removal percent was reported as 97.5% for initial 2 mg L"1 F concentration at a contact period of 80 min (FIG. 4). The difference in the percent F removal might be because of the reduction in the amount of accessible adsorption sites as they are saturated with excess F concentration and less surface area available after converting the composite into rod form.
Leaching of NPs was analyzed through Atomic adsorption spectroscopy (AAS). The developed product showed negligible leaching of nanomaterials as have compact arrangement with polymers in the cellulose tube. The product also showed durability after F adsorption from drinking water and can be reused for the defluoridation of the water samples. As the polymers and nanomaterials utilized are durable and filled in cellulose tube.

We Claims:
1. A defluoridation filter media comprising:
a) Atleast a bottom composite layer comprising polyvinyl alcohol-cellulose acetate-AI2O3 nanoparticle- coconut carbon shell composite;
b) Atleast a top composite layer comprising Cellulose acetate-graphene oxide- AI2O3 nanoparticle composite;
c) Atleast a middle composite layer comprising AI2O3 nanoparticle - polyurethane foam composite.

2. The filter media as claimed in claim 1, comprising said top composite layer, middle composite layer and bottom composite layer is present in a ratio of 50:40:10.
3. The filter media as claimed in claim 1, wherein said AI2O3 nanoparticle is synthesized through green method from jojoba leaf.
4. The filter media as claimed in claim 2, wherein said AI2O3 nanoparticle is synthesized by following steps:

a) adding aluminum nitrate to jojoba leaf extract in approximately 1:3 ratio (w/w) followed by constant stirring at room temperature to obtain a mixture;
b) microwave heating the mixture resulting from step (a) for approximately 7 minutes, to obtain a yellow brown precipitate;
c) centrifuging the precipitate resulting from the step (b) followed by washing by methanol and drying to obtain said AI2O3 nanoparticle.
5. The filter media as claimed in claim 1, wherein said Cellulose acetate-graphene
oxide- AI2O3 nanoparticle composite is prepared by the steps of:
a) preparing 1 g cellulose acetate solution by mixing in approximately 20 ml
acetone;
b) adding approximately 1 g AI2O3 nanoparticle and approximately 10 mg graphene
oxide to the solution resulting from step (a) followed by stirring to obtain a
suspension;
c) Sonicating the suspension obtained from the above step to obtain said Cellulose
acetate-graphene oxide- AI2O3 nanoparticle composite.
6. The filter media as claimed in claim 1, wherein said AI2O3 nanoparticle -
polyurethane foam composite is prepared by the steps of:
a) Suspending AI2O3 nanoparticle in approximately 100 ml of distilled water for sonication
b) Impregnating AI2O3 nanoparticle resulting from step (a) on the polyurethane foam through dip adsorption method to obtain the composite.

7. The filter media as claimed in claim 1, wherein said polyvinyl alcohol-cellulose acetate-AI2O3 nanoparticle- coconut shell composite is prepared by following method:
a) Washing, drying and crushing the coconut shell to uniform powder followed by adding potassium hydroxide to the powdered coconut shell matter;
b) Heating the coconut shell powder resulting from step (a) at approximately 800°C for 2 hours;
c) Rinsing the activated carbons obtained from step (b) followed by drying;
d) Dissolving approximately 1 g of coconut shell powder in approximately 50 ml AI2O3 nanoparticle solution of 1 g concentration to obtain a solution;
e) Treating the solution resulting from step (d) in vacuum oven at approximately 110°C for about 2 h for full coating of AI2O3 nanoparticle onto the coconut shell powder;
f) Preparing a second solution by adding approximately 8g polyvinyl alcohol powder in approximately 100ml water to obtain a suspension followed by adding the glutaraldehyde solution and cellulose acetate;
g) Adding the solution resulting from step (e) with the second solution resulting from step (f) to obtain said polyvinyl alcohol-cellulose acetate-A^Ch nanoparticle-coconut shell composite.