FIELD OF THE INVENTION:
This invention relates to a magnetic nanopolymer and a process for the preparation thereof.
This invention further relates to a magnetic nanopolymer and use thereof for the purification of water.
BACKGROUND OF THE INVENTION:
In recent years, magnetic nanoparticles based water purification has gained attention due to different advantages. Various methods have been developed to synthesize Fe3O4 particles in nanometer size range. However, most of the reported techniques are tedious and costly due to stringent operating condition (need high temperature heating, costly equipments and reagents, nitrogen or argon atmosphere, time consuming, complex reaction techniques). Shen et al. (2009) prepared Fe3O4 nanoparticles in nitrogen atmosphere within 10 to 12 hours at 80° to 90°C. Li et. Al (2008) synthesized Fe3O4 magnetic nanoparticles by hydrothermal method within 6-7 hours at 160°C heating in furnace. Lopez et. Al (2009) prepared Fe3O4 particles by co-precipitation technique that needs above 2 hours and heating upto 80°C. In 2003 Hyeon et al, introduced high temperature decomposition of organic precursors in which FeCup3 (Cup:N-nitrosophenylhydroxylamine) in octylamine into long chain amines produced nano-crystals of Fe3O4 ranging from 4 to 10 nm in diameter at 250°C-300°C. In 2002 Zeng et. Al, introduced an innovative procedure of magnetite preparation by high temperature reaction (265°C) of iron (III) acetylascetonate in phenyl ether in presence of alcohol, oleic acid and oleylamine. K.L. Liu, Y.D. Du, Y. Q. Wang (2011) introduced magnetic Fe3O4 nanoparticles preparation by sol-gel

method at 923K within 12 to 13 hours in argon atmosphere. Ianos et. Al (2012) experimented magnetite prepared by solution combustion method in N atmosphere at 400°C temperature.
However, most of the available techniques are complex, costly and need stringent operating conditions.
OBJECTS OF THE INVENTION:
It is therefore an object of this invention to propose a magnetic nanopolymer for water purification, which can be prepared using simple techniques and easily available materials.
It is a further object of this invention to propose a magnetic nanopolymer for water purification, which can be prepared quickly and efficiently and is cost-effective.
Another object of this invention is to propose a magnetic nanopolymer for water purification, which is prepared using non-toxic chemicals.
Yet another object of this invention is to propose a magnetic nanopolymer for water purification, which shows great dispersion stability.
A further object of this invention is to propose a magnetic nanopolymer for water purification, which is a strong adsorbent of suspended and dissolved particles, heavy metals and microorganisms in a stand alone system.
These and other objects of the invention will be apparent from the ensuing description, when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Fig. 1 (a)TEM picture of nanoparticles (b) Particle size distribution
(c) Zeta potential of particles at different pH
(d) 1R spectra of magnetic polymer.
Fig. 2: (a) SEM image of E.coli cells without nanoparticles treatment (b) SEM image of E.coli cells after nanoparticles treatment
BRIEF DESCRIPTION OF THE INVENTION:
Thus according to this invention is provided a magnetic nanopolymer, a process for the preparation thereof and a process for the purification of water using the nanopolymer.
In accordance with this invention, the magnetic polymer is prepared by a very simple and low cost technique. It is prepared by two methods
1) Generation of magnetic nano-particles of Fe3O4 separately using
capping agent like amino-alcohol followed by mixing with polymer like
a) starch mixed with chitosan (50% to 5% w/w) or b) starch embedded
with poly diallyl dimethyl ammonium chloride (polyDADMAC) (1-5% w/w)
maintaining the same weight ratio magnetic oxide and polymer (1:1 w/w
to 1:5w/w).
2) Generation of magnetic polymer in single step where cationic polymer
like a) starch mixed with chitosan (50% to 5% w/w) or b) starch
embedded with poly diallyl dimethyl ammonium chloride (polyDADMAC)
(1-5% w/w) is mixed with ferric salt and ferrous salt (mole ratio 2 :1)
followed by addition sodium hydroxide solution (10-50% w/w) to attend
the final pH close to 7. This procedure will generate magnetic
nanoparticle in situ within the polymer.

The preparation time of such nanopolymer is much less (few minutes) than any other available conventional technique.
For the method 1) Typically 1 to 4g FeCl3 and 0.5 to 2.0g FeSO4 are dissolved in 50-100ml of distilled water at room temperature so that mol ratio Fe3+ : Fe2+ = 2: 1. To this 30% ammonium hydroxide or sodium hydroxide solution (of any concentration preferably 10-50% w/w) is added under vigorous stirring for 2 to 5 minutes till final pH is close to 7. A capping agent is added into the solution before adding ammonium hydroxide or sodium hydroxide, to obtain a precipitate. The precipitate is then thoroughly washed with distilled water and then with acetone. The magnetic nanoparticles of Fe3O4 are then dried at room temperature and ground into fine powder. A stock solution of magnetic polymer is prepared by dispersing magnetic iron oxide (Fe3O4) nanoparticles and polymer in distilled water. The solution is stirred for about 30 minutes and used without further modification.
The capping agent may be selected from an amine alcohol such as triethanolamine, diethanolamine and ethanolamine, preferably triethanolamine for the method 1.
The polymer is preferably a cationic polymer selected from pure chitosan, starch mixed with chitosan (50% to 5%) and starch embedded with poly diallyl dimethyl ammonium chloride (polyDADMAC) (1-5% w/w) maintaining the same weight ratio magnetic oxide and polymer (1:1 -1:5w/w) where chitosan is used as the polymer, a separate capping agent is not used and chitosan may act as the capping agent and polymer. At normal pH of drinking water in the range of 6 to 7, the nanoparticles are positively charged.

The invention will now be explained in greater details with the help of the following non-limiting example.
EXAMPLE:
2.00 g of FeCl3 and 1.00g of FeSO4 were dissolved into 50 ml of distilled water at room temperature. To this 20 ml of 30% ammonium hydroxide was added under vigorous stirring for two minutes. 5ml of triethanolamine was quickly added into the solutions as capping agent. The black precipitate was then thoroughly washed with distilled water and then with acetone. The magnetic nanoparticles were then dried at room temperature and grinded into fine powder.
A stock solution of magnetic polymer was prepared by dispersing magnetic iron oxide (Fe3O4) nanoparticles (0.5g) and polymer (0.5g) in 50 ml of distilled water, The solution was then stirred for 30 minutes and the magnetic polymer formed, was used without further modification.
The produced magnetic iron oxide nanoparticles exhibit excellent magnetic property and stability. Furthermore, the invention iron nanoparticles are applied in water purification in presence of cationic polymer to remove suspended solid, dissolved solids and microbes in a single system. The chemicals used in this process are cheaper and non toxic in nature. Unlike other conventional techniques the invented technology requires simplest experimental conditions. The invented magnetic iron oxide nanoparticles can be synthesized within five minutes, whereas other conventional techniques need an average time of 8 to 10 hours. The invented nanoparticles exhibit great dispersion stability (upto 8 months) in water, DMF, acetone, ethanol, hexane etc.

The efficacy of produced iron oxide magnetic polymer particles in water purification has been experimented with highly turbid dirty water collected from road side nalla. The dirty sample water was poured in a beaker, to this magnetic iron oxide nanoparticles were suspended along with cationic polymer. After few minutes stirring the beaker is kept on a magnet to separate the impurities. Results show successful removal of suspended solid, dissolved solid and microbes through adsorption within few minutes. Thus this technology is an effective alternative of available tedious filtration techniques and can easily be applied to purify gallon of water within short time in adverse situation like natural calamities (flood), war camps etc.
Raw water was treated with above magnetic polymer and stirred for 15-30 min. On application of a magnetic field, the magnetically coagulated material containing bacteria, suspended particles, heavy metals separated out.
The novelty of the method resides in the bulk production of magnetic iron oxide nanopolymer with a size range of 10-20 nm. The nanopolymer are produced at room temperature so no need of external heating. The procedure of nanoparticles synthesis is faster (average time is five minutes) than any other available conventional methods and doesn't need any stringent operating condition like nitrogen or argon atmosphere, high temperature, external power, costly chemicals etc and it is an easy one bulk synthesis of magnetic iron oxide nanoparticles within 5 minutes. The synthesized nanopolymer particles are highly magnetic and show great dispersion stability (upto 8 months) in water, DMK, acetone, ethanol and hexane. The nano act as strong adsorbent of

suspended particles, dissolved particles, heavy metals, microorganisms in a standalone system. The produced magnetic iron oxide nanoparticles show strong adsorption property and can easily be used to purify gallon of water within few minutes by magnetic decantation. Hence, the invented technology is much faster than membrane technology. The technology provides a more effective alternative to the usually slow and tedious process of water filtration (such as membrane filtration).
The coated nanoparticles have been tested for their performance. The phase analysis of the synthesized coated magnetite nanopowder was performed on an X'pert Pro Phillips x-ray diffractometer, showing the mean crystalline size around 8 nm. High-resolution transmission electron microscopy (JEOL 3010, Japan) was employed to characterize the microstructure of the coated nanoparticles, exhibiting 10 to 20 nm (Fig. 1a). The particle distribution shown Fig 1b. The zeta potential of the nanoparticles was measured in the laboratory by particle size analyzer (DTS Ver. 5.00; Malverb Instruments Ltd.) and Fig 1c shows the zeta potential of the particles at different pH. FTIR was performed by
PerkinElmer Spectrum 100 spectrommeters, USA (Fig 1d), showing successful formation of the magnetic nanopolymer. Turbidity, TDS, particle size, pH and microbial analysis of raw water sample (untreated highly turbid dirty water) and iron oxide nanoparticles treated water has been experimentally tested in laboratory. The results shown in table I support the efficacy of invented nanoparticles to remove suspended solids, dissolved solids and microbes.


Fig. 2a shows the SEM image of E. coli cells without nanoparticle treatment and Fig 2b shows the SEM image of E. coli after treatment with the nanoparticles).

WE CLAIM:
1. A magnetic nanopolymer comprising magnetic iron oxide nanoparticles (Fe3O4) treated with a cationic polymer.
2. The magnetic nanopolymer as claimed in claim 1, wherein the polymer is a cationic polymer.
3. The magnetic nanopolymer as claimed in claim 1 and 2, wherein the polymer is pure chitosan, starch mixed with chitosan (50% to 5%) and starch embedded with poly diallyl dimethyl ammonium chloride (polyDADMAC) (1-5% w/w).
4. The magnetic nanopolymer as claimed in claim 1, wherein magnetic oxide and polymer are present in a ratio of 1:1 w/w to 1:5w/w.

5. The magnetic nanopolymer as claimed in claim 1, wherein said nanopolymer has a particle size in the range of 10 to 20 nm.
6. A process for the preparation of a magnetic nanopolymer comprising the steps of preparing a solution of a ferrous salt and a ferric salt, adding ammonium hydroxide or sodium hydroxide thereto with stirring, followed by quickly adding a capping agent thereto, to obtain a black precipitate of the magnetic nanoparticles, drying the same to obtain a powder, dispersing the powder and a polymer in water, followed by stirring the same to obtain the magnetic nanopolymer.
7. The process as claimed in claim wherein mole ratio of ferric salt to ferrous salt is 2:1

8. The process as claimed in claim 5, wherein ammonium hydroxide or sodium hydroxide is added quickly, over 2 to 5 minutes.
9. The process as claimed in claim 5, wherein the capping agent is an amine alcohol when it follows the process 1.

10. The process as claimed in claims 5 and 9, wherein the amine alcohol is selected from triethanolamine, diethanolamine and ethanolamine.
11. The process as claimed in claim 5, wherein the polymer is a pure chitosan, starch mixed with chitosan (50% to 5%) and starch embedded with poly diallyl dimethyl ammonium chloride (polyDADMAC) (1-5% w/w).
12. The process as claimed in claim 5, wherein the iron oxide and
polymer are used in a proportion of 1:1 w/w to 1: 5 w/w.