WO2017002137A1

WO2017002137A1 - Sustainable biomaterial nanocomposites for water treatment and process for preparation thereof

Info

Publication number: WO2017002137A1
Application number: PCT/IN2016/050216
Authority: WO
Inventors: Parimal Paul; Sanna Kotrappanavar NATARAJ; Anshu KUMAR; Pradeep Kumar PRAJAPATI
Original assignee: Council Of Scientific & Industrial Research
Priority date: 2015-07-01
Filing date: 2016-07-01
Publication date: 2017-01-05

Abstract

Invention discloses a sustainable biomaterial Scaffold (BMS) nanocomposites useful for removal of fluoride, reactive black and Cr(VI) for water purification and process for the preparation of biomaterial Scaffold (BMS) nanocomposites. Its application in removal of fluoride (F-), chromium (Cr(VI)) and color contaminants from water is reported. This BMS nanocomposite exhibited as high as ~168 mg g-1 and ~60 mg g-1 fluoride uptake efficiency at pH 4 and pH 7 respectivily, and ~8.5 mg g-1 Cr(VI) uptake capacity. With this material, >99 % reactive black-5 (RB-5) removal was achieved with remarkable surface regeneration property.

Description

SUSTAINABLE BIOMATERIAL NANOCOMPOSITES FOR WATER

TREATMENT AND PROCESS FOR PREPARATION THEREOF

FIELD OF THE INVENTION

Present invention relates to sustainable biomaterial Scaffold (BMS) nanocomposites for water treatment. Particularly, present invention relate to a process for the preparation of biomaterial Scaffold (BMS) nanocomposites useful for removal of Fluoride, reactive Black and Cr(VI) for water purification.

BACKGROUND OF THE INVENTION

Reference may be made to the article by Jie Liua et al. in Applied Surface Science, 2014, 293, 46-54, wherein titanium(IV) hydrate based on Chitosan template (Ti- CHI), was synthesized using Ti(S04)₂ and Chitosan for defluoridation from aqueous solutions is disclosed.

Reference may be made to the review by Eva Kumar et al. In Chemical Engineering Journal, 2014, 241, 443-456, wherein Various phases of aluminum (Al) oxides, hydroxides and oxyhydroxide are increasingly being employed as adsorbents for the detoxification of water and wastewater contaminated with anionic pollutants is disclosed.

Reference may be made to the article by Jianqing Ma et al. in Chemical Engineering Journal, 2014, 248, 98-106, wherein aluminum and doping Chitosan-Fe(III) hydrogel (Al-CS-Fe) was prepared and investigated as a possible adsorbent for the removal of fluoride from aqueous solutions is disclosed.

Reference may be made to the article by H. Basu et al. in Water Air Soil Pollutant, 2013, 224, 1572, wherein alumina impregnated calcium alginate beads to sorb the excess fluoride ions from the potable water is disclosed.

Reference may be made to the article by Vivek Ganvir et al. in Journal of Hazardous Materials, 2011, 185, 1287-1294, wherein effective defluoridation method that is based on surface modification of rice husk ash (RHA) by coating aluminum hydroxide from water is disclosed.

Reference may be made to the review by Patricia Miretzky et al. in Journal of Fluorine Chemistry, 2011,132, 231-240, wherein Fluoride removal in water treatment, using Chitosan derivatives and composites in order to provide useful information about the different technologies is disclosed.

Reference may be made to an article by Xiaoli Zhao et al. in Journal of Hazardous Materials, 2010, 173, 102-109, wherein magnetic nanosized adsorbent using hydrous aluminum oxide embedded with Fe₃04 nanoparticle (Fe₃04@Al(OH)₃ NPs), was prepared and applied to remove excessive fluoride from aqueous solution is disclosed.

Traditionally, there are several multi-step defluoridation treatment units in use in rural neighborhoods. Despite the fact that many adsorption/absorption-based technologies have been tested to address fluoride epidemic and colored wastewater, yet simple and sustainable methods are still in demand. Activated alumina and bone char are some of commercially successful methods available to treat fluoride contamination. In addition, ion-exchange resins are being considered user friendly and relatively stable fluoride chelating agents. Membrane process like nanofiltration, reverse osmosis and electrodialysis are also widely used technologies for treating fluoride contamination and wastewater. However, many of above described processes economically classified in the range of medium to very high cost.

OBJECTS OF THE INVENTION

The main object of the present invention is to provide sustainable biomaterial Scaffold (BMS) nanocomposite for water treatment.

Another object of the present invention is to prepare superior alternatives to conventional and sustainable biomaterial Scaffold (BMS) nanocomposite for removal of fluoride and color black (reactive black).

Yet another objective of the of the present invention is to provide sustainable biomaterial Scaffold (BMS) nanocomposite to remove Cr(VI) from contaminated water. Yet another object of the present invention is to provide formation of biomaterial Scaffold (BMS) nanocomposites in Bayerite form at room temperature (RT).

Still another object of the present invention is to develop biomaterial Scaffold (BMS) nanocomposite for removal of fluoride as a form of Ralstonite at RT.

Still another object of the present invention is to develop carbon material derived from BMS- Ralstonite for super capacitor application.

Yet another object of the present invention is to develop biomaterial Scaffold (BMS) nanocomposite derived from fluoride adsorbed BMS (Ralstonite) act as hydrophilic surface and used for oil water separation.

Yet another object of the present invention is to develop biomaterial Scaffold (BMS) nanocomposite for removal of color (Reactive Black) in water and recovery 80% (wt.) in Methanol.

Yet another object of the present invention is to develop biomaterial Scaffold (BMS) nanocomposite for removal of Cr(VI) in water and recovery 84% (wt.) Cr(VI) by NaOH treatment.

Yet another object of the present invention is to make very simple technique to removal of color (reactive black), Cr(VI) and Fluoride by using tea bag and column method under gravitational force.

Still another object of the present invention is to use naturally occurring polysaccharides, nonhazardous as major chemical for synthesis.

SUMMARY OF THE INVENTION

Accordingly, present invention provides a sustainable biomaterial scaffold(BMS) nanocomposite comprising:

i. seaweed derived polysaccharides in the range of 50-95 wt%;

ii. amino polysaccharides in the range of 5-50 wt%; and

iii. cross linker in the range of 0.2 to 0.8 M;

iv. Silver nanoparticles in the range of 0.0025 to 0.005wt%. In an embodiment of the present invention, the seaweed derived polysaccharides used is sodium alginate.

In another embodiment of the present invention, the amino polysaccharides are selected from Chitosan and Chitin.

In another embodiment of the present invention, the cross linker used is water soluble aluminum salt.

In yet another embodiment of the present invention, the water soluble aluminum salt is selected from the group consisting of A1₂(S0₄)₃, A1(N0₃)₃ and AlCl₃.xH₂0.

In yet another embodiment, present invention provides a process for the preparation of the hydrophilic biodegradable biomaterial scaffold (BMS) nanocomposite comprising the steps of:

a) dissolving 5 to 50 wt% of the seaweed derived polysaccharides in water by stirring at room temperature in the range of 20 to 30°C to obtain a homogenous solution; b) adding 50 to 95 wt% amino polysaccharide solution of 0.5% HN0₃ at room temperature in the range of 20 to 30°C in aqueous medium under constant stirring for period in the range of 1 to 30 min;

c) mixing the solution as obtained in step (a) and (b) followed by adding 0.2-0.8 M cross linker and keeping at room temperature in the range of 20 to 30°C for period in the range of 50 to 60 minute to obtain the cross-linked solid mass;

d) treating the cross-linked solid mass as obtained in step [c] with 1 to 2M NaOH at temperature in the range of 25° to 28 °C followed by stirring for period in the range of 50 to 60 minute and washing to obtain the precipitate;

e) coating the precipitate as obtained in step (d) with 0.0025 to 0.005 wt% silver nanoparticle with stirring followed by washing and drying at temperature in the range of 28 to 100°C to obtain biomaterial scaffold(BMS) nanocomposite.

In yet another embodiment of the present invention, the composites is useful for removal of fluoride, reactive black and Cr(VI) for water treatment. In yet another embodiment of the present invention, the nanocomposites is useful for removal of Fluoride, reactive Black and Cr(VI) for water treatment in tea bag like pouches, column filter or Hollow Fiber Water Treatment Kit.

In yet another embodiment of the present invention, the nanocomposites exhibit fluoride uptake efficiency is in the range of -60 mg ^ 10 -168

In yet another embodiment of the present invention, the nanocomposites exhibit Cr(VI) uptake efficiency is 8.5 mg g^"1.

In yet another embodiment of the present invention, the nanocomposites exhibit removal capacity of reactive black in the range of 95 to 99%.

In an embodiment, the present invention provides a process which uses alginate, and Chitosan as the polysaccharides to be synthesize Biomaterials Scaffold (BMS) Nanocomposite.

BRIEF DESCRIPTION OF THE DRAWING

Figure 1 represents (a) Synthetic route of biomaterials scaffold (BMS) nanocomposite preparation from Chitosan, Na-alginate and aluminium precursors and finally BMS surface modification through Ag nanoparticle layer, (b) TEM images showing layered structure of BMS with discernible Al⁺³-Alginate clusters and (c) Schematical evaluation of BMS formation.

Figure 2 represents photograph and schematic column configured experimental set-up to show Reactive black dye removal before and after.

Figure 3 represents Photograph BMS nanocomposite in tea bag configured experimental setup to show time dependent Reactive black (RB) dye removal. UV plot to confirm the RB's concentration reduction in feed stock with time. Activity of BMS nanocomposite regenerated by washing in methanol and tested for several cycles to for dye removal efficiency.

Figure 4 represents indigenous BMS nanocomposite compartmentalized hollow fiber water treatment kit. Figure 5 represents graphical representation of biomaterial scaffold (BMS) and its application in water treatment using tea bag like pouches.

DETAIL DESCRIPTION OF THE INVENTION

Present invention relates to the application of bio-derived functionalized nanomaterial useful in combination with hollow fiber membranes as an efficient water treatment kit for domestic usage. Chitosan and Na-alginate are considered as green materials and can be easily obtained from renewable bio-mass resources. Bio-materials Scaffold (BMS) bed was designed to retain large volume toxic dyes and fluoride in a column filter. Tea-bag configuration was evaluated in a series of experiments to assess the feasibility of domestic usage. BMS actively uptake -174 mg.g^"1 of fluoride at 8.5 pH, while 99.99 % removal of Reactive Black achieved using both filter and tea-bag-like pouches. BMS are biodegrade within 10-15 days, to enhance life shelf-life of BMS composite surface was further modified by coating silver nano particles. It was determined that, AgNPs only increase life span of BMS without interfering results. This invention stands as a viable, sustainable, cost-effective and environmentally benign solution to provide safe and clean drinking water from domestic water streams. To characterize BM's retention properties, in Step-1, individual experiments have been carried out with dye (reactive black), fluoride and chromium.

Chitosan-alginate based biomaterial scaffolds (BMS) with in-situ functionlized alumina hydroxide networks and enhances the shelf life, growing Ag NPs on the surface of the BMS . Its application in removal of fluoride (F-), chromium (Cr(VI)) and color contaminants from water is reported. This BMS nanocomposite exhibited as high as -168 mg g-1 and -60 mg g-1 fluoride uptake efficiency at pH 4 and pH 7 respectively, and -8.5 mg g-1 Cr(VI) uptake capacity. With this material, >99 % reactive black-5 (RB-5) removal was achieved with remarkable surface regeneration property. As a part of its application for purification of water, BMS nanocomposite was tested in tea-bags like pouches and column filter mode in a series of experiments to assess the feasibility of domestic usage and the results are excellent. This study appears as a viable and sustainable solution for removal of fluoride, chromium(VI) and color contaminants from drinking water.

Synthesis of Biomaterials Scaffold (BMS) Nanocomposite

Present invention relates to the synthesis of polysaccharides based Biomaterials Scaffold (BMS) Nanocomposite for color (reactive black), Cr(VI) and fluoride removal through sustainable process. Figure 1 gives BMS synthesis route and characterization details. A process for the preparation of the hydrophilic biodegradable biomaterial scaffold (BMS) nanocomposite comprising the steps of:

a) dissolving 5 to 50 wt% of the seaweed derived polysaccharides in water by stirring at room temperature in the range of 20 to 30°C to obtain a homogenous solution; b) adding 50 to 95 wt% amino polysaccharide in the solution of 0.5% HNO₃ at room temperature in the range of 20 to 30°C in aqueous medium under constant stirring for period in the range of 1 to 30 min;

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a three-step process: (i) 0.5-2 g Chitosan was dissolved in 0.5% nitric acid solution, (ii) 0.5-2 g Sodium Alginate was dissolved in 100ml water solution was added drop wise in solution of step (i). (iii) 100 ml of 0.5M aluminium sulphate was added and further 140 mL of 1-2 M sodium hydroxide was added drop wise to precipitate aluminium, Na- Alginate and Chitosan (referred to as Bayerite Bio-Material). The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (ii) Further, BMS was surface modified with silver nanoparticle: After re- dispersing the precipitate in water, 100 mL of 5-10 mM silver nitrate was added and incubated for 1 h. Afterwards, 100 mL of 20 mM sodium borohydride was added drop wise and the mixture was stirred continuously. The final precipitate was subsequently washed with copious amounts of water, dried at temperature (28-100°C), crushed, and used for further studies. Fluoride and Dye Removal Studies by Column Filter Method

Therefore, present invention aims to develop bio-derived nanomaterial as an efficient and sustainable media to fluoride and colored wastewater in simple and robust user modules. Also, easy to use design and packing makes green nanomaterials more attractive. Natural polymers like Chitosan and Na-alginate in combination with alumina precursor in scaffold morphologies have shown greater fluoride and color removal efficiencies.

BMS nanocomposite having both basal and edge active surfaces was directly tested for anion uptake efficiency in tea-bag format. In a simple and affordable design of rectangle shaped porous nylon sealed bang containing BMS was tested. At different pH conditions uptake level was in the range of 166 mg g^"1 to 174 mg g^"1. In a robust process active BMS absorbs fluoride as high as 174 mg g^"1 at pH 8.5.

Further, reactive dye (RB-5), a commonly used for coloring cellulosic fabric has been used to test the retention property of BMS. Reactive black dissociates to attain negatively charged moiety in water instantly interact with BMS in filter bed form as shown Figure 2(a). Loosely packed cake placed in between macroporous fabric retains >99 % color from initial 500 mg L^"1 feed stock. UV analysis of permeate at different time interval revealed higher dye retention capacity of BMS. Initially 99.99 % removal of efficiency of RB-5 recorded which remain constant for a period of 240 min (Figure 2(b)). Even though flux decline was observed with 1 g of active BMS cake under gravity, additional applied pressure retained significant flux with slight loss in rejection (-97 %). To alter the packing density of BMS during filter making, different compositions of scaffolds were prepared and tested for their rejection performance. In column filter 1 gm of active BMS is filled in filtrate chamber at the dead end of column. The column is connected to fluoride or chromium or dye contaminated feed. Under gravitational force, contaminated feed solution passes through BMS active materials fitted at the dead end of column allowing fluoride or chromium or dye to be absorbed. The permeate obtained after passing through BMS active material is purified water.

Tea-Bag-Like Pouches Method

Knowing targeted end user from rural and semi-urban population it is important to demonstrate robustness of the product for contaminated dye and fluoride water samples. Hence, an easy to use and store module of tea-bag like pouches containing 1 g of BMS were prepared and tested against reactive block dye as shown in Figure 3(a).

To monitor the robustness, timer was fixed next to 500 mg L^"1 containing beaker. Once the BMS pouch was inserted, time dependent adsorption process was quantified under constant stirring conditions. From Figure 3(b) it is clear that ~4 h of stirring 100 mL RB-5 with 500 mg L^"1 stock solution turned transparent solution. Further, sampling was done every 30 min to record the percent color adsorption on BMS. UV-vis spectrum recorded from as collected sample as shown in Figure 3(c). Further, BMS containing pouch was washed in methanol and repeated several cycles to know the recyclability of the material. The BMS has shown excellent surface regeneration and reusability for 500 mg L^"1 dye feed stock. Figure 3(d) indicates in first 3 cycles >95 % color removal was achieved in ~5 h of stirring.

BMS Nanocomposite-Hollow Fiber Water Treatment Kit

Further, BMS nanocomposite compartmentalized hollow fiber membrane hybrid water treatment kit is being tested as final target module as shown in Figure 4.

EXAMPLES

Following examples are given by way of illustration and therefore should not be construed to limit the scope of the invention.

Chitosan, Sodium Alginate, Sodium borohydride and Reactive Black 5 used in the present invention were purchased from sigma Aldrich. Example 1

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na- Alginate) polysaccharides in 100 ml water by stirring at room temperature (30°C) to obtain a homogenous solution, (ii) adding 0.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature in aqueous medium under constant stirring for 30 min (iii) adding 100 ml of 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 140ml of 2M NaOH at 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step (iv) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 87% for fluoride, 90% for reactive black and 57% of Cr(VI) with A1^J+ leaching was observed.

Example 2

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na- Alginate) polysaccharides in water by stirring at room temperature (24 °C) to obtain a homogenous solution, (ii) adding 1 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature in aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 2M NaOH at 27°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the obtained BMS as obtained in step iv (biomaterial scaffold) is coated with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 90% for fluoride, 92% for reactive black and 62% of Cr(VI) with Al³⁺ leaching was observed.

Example 3

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 27°C to obtain a homogenous solution, (ii) adding 2 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature in aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 2M NaOH at 27°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the obtained BMS as obtained in step iv (biomaterial scaffold) is coated with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 90% for fluoride, 92% for reactive black and 62% of Cr(VI) with Al³⁺ leaching was observed.

Example 4

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 0.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 30°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature 30°C in aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature 30 °C for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 2M NaOH at temperature in the range of 24° to 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 72% for fluoride, 62% for reactive black and 71% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.4 L g^-1 h^_1.

Example 5

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 30°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature 30°C in aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature 30 °C for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 2M NaOH at temperature in the range of 24° to 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 78% for fluoride, 72% for reactive black and 80% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.5 L g ¹ h ^l.

Example 6

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 2 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 30°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HNO₃ at room temperature 30°C in aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature 30 °C for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 2M NaOH at temperature in the range of 24° to 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 92% for fluoride, 94% for reactive black and 93% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g^-1 h^_1.

Example 7

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 30°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature 30°C in aqueous medium under constant stirring for 30 min (iii) adding 0.2 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature 30 °C for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 2M NaOH at temperature in the range of 24° to 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 52% for fluoride, 58% for reactive black and 55% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g^-1 h^_1. Example 8

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 30°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature 30°C in aqueous medium under constant stirring for 30 min (iii) adding 0.3 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature 30 °C for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 2M NaOH at temperature in the range of 24° to 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 62% for fluoride, 65% for reactive black and 68% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g^-1 h^_1.

Example 9

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 30°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature 30°C in aqueous medium under constant stirring for 30 min (iii) adding 0.4 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature 30 °C for 3 h to obtain the crosshnked solid mass, (iv) treating the crosshnked solid mass as obtained in step (iii) with 2M NaOH at temperature in the range of 24° to 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 75% for fluoride, 77% for reactive black and 78% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g ¹ h ^l.

Example 10

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 25°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature in aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature in the range of 24 to 30 °C for 3 h to obtain the crosslinked solid mass, (iv) treating the crosslinked solid mass as obtained in step (iii) with 2M NaOH at temperature in the range of 24° to 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 94% for fluoride, 95% for reactive black and 93% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g^"1 h^"1.

Example 11

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 24 °C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature in aqueous medium under constant stirring for 30 min (iii) adding 0.6 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature for 3 h to obtain the crosslinked solid mass, (iv) treating the crosslinked solid mass as obtained in step (iii) with 2M NaOH at 24°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 94% for fluoride, 95% for reactive black and 93% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g^-1 h^_1 (Figure 2).

Example 12

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 30°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature in aqueous medium under constant stirring for 30 min (iii) adding 0.8 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature for 3 h to obtain the crosslinked solid mass, (iv) treating the crosslinked solid mass as obtained in step (iii) with 2M NaOH at 30°C followed by stirring for 1 hr. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water, (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 94% for fluoride, 95% for reactive black and 93% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g^"1 h^"1.

Example 13

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na- Alginate) polysaccharides in water by stirring at room temperature 24 °C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature in aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature for 3 h to obtain the crosslinked solid mass, (iv) treating the crosslinked solid mass as obtained in step (iii) with 2M NaOH at 27°C followed by stirring for 1 hr. (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water and dried at room temperature (28°C), Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 94% for fluoride, 95% for reactive black and 93% of Cr(VI) with A1^J+ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g ¹ h ^l.

Example 14

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature 25°C to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperature in aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature for 2 h to obtain the crosslinked solid mass, (iv) treating the crosslinked solid mass as obtained in step iii with 2M NaOH at 30°C followed by stirring for 1 hr. (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water and dried at 60°C, Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 95% for fluoride, 95% for reactive black and 95% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g^-1 h^_1.

Example 15

An aluminum based Na-Alginate-Chitosan bed [Al(OH)₃] nanostructure embedded with silver nanoparticles was synthesized by a five-step process: (i) dissolving 1.5 gm of the seaweed derived (Na-Alginate) polysaccharides in water by stirring at room temperature (30°C) to obtain a homogenous solution, (ii) adding 1.5 gm amino polysaccharide (Chitosan) in the solution of 0.5% HN0₃ at room temperaturein aqueous medium under constant stirring for 30 min (iii) adding 0.5 M crosslinker (Aluminum sulphate) into the reaction mixture as obtained in step (i and ii) followed by keeping at to room temperature for 3 h to obtain the crosslinked solid mass, (iv) treating the crosslinked solid mass as obtained in step iii with 2M NaOH at 30°C followed by stirring for 1 hr. (v) coating the BMS as obtained in step iv (biomaterial scaffold) with 0.005 wt% silver nanoparticle to obtain biomaterial scaffold (BMS) nanocomposite. The resultant precipitate was further stirred for 1 h and subsequently washed with copious amounts of water and dried at 100°C, Resultant biomaterials Scaffold (BMS) nanocomposite having good removal capacity 97% for fluoride, 95% for reactive black and 96% of Cr(VI) with Al³⁺ leaching was observed. Water was separate out from contaminated water with flux 0.7 L g^-1 h^_1. ADVANTAGES OF THE INVENTION

• The separations of contaminated of natural and industrial hazardeous and molecules with different mixtures including fluoride, Cr(VI) mixture and Reactive black mixtures inevitably requires the use of suitable materials and that the non- biodegradability of existing materials can pose a serious threat where separation is undertaken on very large scale, leading to massive problem of pollution with solid waste. The present invention provides a solution to the problem by providing biodegradable hydrophilic BMS nanocomposite which can be used for energy-efficient and eco- friendly water purification material.

Recognizing that, preparation of hydrophilic biocompatible Biomaterial scaffold nanocomposite using eco-friendly materials.

Recognizing that, preparation of hydrophilic biocompatible Biomaterial scaffold nanocomposite using natural polymers.

Recognizing that, preparation of hydrophilic biocompatible Biomaterial scaffold nanocomposite using seaweed derived polysaccharides.

Recognizing that, preparation of hydrophilic biocompatible Biomaterial scaffold nanocomposite using hybrids of natural polymers.

Recognizing that, preparation of hydrophilic biocompatible Biomaterial scaffold nanocomposite using hybrids of seaweed polysaccharides and other biopolymers. Recognizing that, Use of bio-based scaffolds embedded with functional nanoparticle for brackish water and wastewater treatment.

Recognizing that, Biomaterial scaffold nanocomposite was tested for their fluoride and color removal efficiencies in filters bed form and novel tea-bag-like pouches. Recognizing that, Biomaterial scaffold nanocomposite removes effectively several anions at low pressure, stirring condition and works effectively at room temperature. Recognizing that, Biomaterial scaffold nanocomposite pouches and filters are easy to recover and reuse with one step recovery process which adds value to the sustainable factor.

Recognizing that, Along with tea-bag like pouches and filters, BMS nanocomposite can be incorporated in a compartmentalized hybrid kit to retain anions further assisting hollow fibers to retain bacteria, virus, and other suspended particles. This makes kit useful alternative to rural and semi-urban population to afford cheap and safe drinking water

Claims

We Claim

1. A sustainable biomaterial scaffold(BMS) nanocomposite comprising:

a. seaweed derived polysaccharides in the range of 50-95 wt%;

b. amino polysaccharides in the range of 5-50 wt%; and

c. cross linker in the range of 0.2 to 0.8 M;

d. Silver nanoparticles in the range of 0.0025 to 0.005wt%.

2. The nanocomposite as claimed in claim 1, wherein the seaweed derived polysaccharides is sodium alginate.

3. The nanocomposite as claimed in claim 1, wherein the amino polysaccharides are selected from the group consisting of chitosan and chitin.

4. The nanocomposite as claimed in claim 1, wherein the cross linker is water soluble aluminum salt.

5. The nanocomposite as claimed in claim 1 and 4, wherein the water soluble aluminum salt is selected from the group consisting of A1₂(S0₄)₃, A1(N0₃)₃ and AlCl₃.xH₂0.

6. A process for the preparation of the hydrophilic biodegradable biomaterial scaffold (BMS) nanocomposite comprising the steps of:

a) dissolving 5 to 50 wt% of the seaweed derived polysaccharides in water by stirring at room temperature in the range of 20 to 30°C to obtain a homogenous solution;

b) adding 50 to 95 wt% amino polysaccharide in the solution of 0.5% HN0₃ at room temperature in the range of 20 to 30°C in aqueous medium under constant stirring for period in the range of 1 to 30 min;

c) mixing the solution as obtained in step (a) and (b) followed by adding 0.2-0.8 M cross linker and keeping at room temperature in the range of 20 to 30°C for period in the range of 50 to 60 minute to obtain the cross-linked solid mass; d) treating the cross-linked solid mass as obtained in step [c] with 1 to 2M NaOH at temperature in the range of 25° to 28°C followed by stirring for period in the range of 50 to 60 minute and washing to obtain the precipitate; e) coating the precipitate as obtained in step (d) with 0.0025 to 0.005 wt% silver nanoparticle with stirring followed by washing and drying at temperature in the range of 28 to 100°C to obtain biomaterial scaffold(BMS) nanocomposite.

7. The nanocomposite as claimed in claim 1, wherein the nanocomposites for use in removing of fluoride, reactive black and Cr(VI) for water treatment.

8. The nanocomposite as claimed in claim 1, wherein said nanocomposites for use in removing of fluoride, reactive black and Cr(VI) for water treatment is in pouches or column filter or hollow fiber water treatment kit.

9. The nanocomposite as claimed in claim 1, wherein the nanocomposites exhibit fluoride uptake efficiency is in the range of -60 mg g^"1 to -168 mg g^"1 .

10. The nanocomposite as claimed in claim 1, wherein Cr(VI) uptake efficiency of the nanocomposites is 8.5 mg g^"1.

11. The nanocomposite as claimed in claim 1 , wherein the nanocomposites exhibit removal capacity of reactive black in the range of 95 to 99%.