Title of Invention

"A PROCESS FOR PREPARTION OF A SYNERGISTIC COMPOSITION USEFUL FOR THE REMOVAL OF ARSENIC FROM WATER"

Abstract This invention relates to an improved process for the preparation of a synergistic composition useful for the removal of arsenic from water which comprises conventional mixing of complexing and coprecipitating agent 73% to 87%, oxidizing agent 9% to 18% and adsorbing agent 4% to 10%.
Full Text The present invention relates to a composition useful for the removal of arsenic from water and capsules/tablets made from the said composition. Arsenic is a commonly occurring toxic metal in natural ecosystem. It may originate from geochemical reactions, industrial wastes or arsenical pesticides. When its concentration gets increased (>0.05 ppm) in ground water which ultimately is used for drinking purposes, it results in the incidence of many diseases caused by arsenic poisoning amongst the people, drinking such water. Incidence of arsenic contamination in ground water and consequent sufferings of the people from chronic arsenic toxicity are reported from different parts of the globe. But the problem reported from the seven districts of West Bengal, India, surpasses all other reported cases as more than 1,75,000 villagers are showing advanced manifestations of arsenic toxicity. Thus the development of a cost effective treatment method for the removal of arsenic from drinking water becomes an imperative. The concerted efforts of the Geo-scientists, Engineers, Planners and Administrators of both state and central organisations, universities and research institutes and NGO's have already made some progress in mitigating the problem of arsenic menace in the state of West Bengal by harnessing surface water, completely circumventing the use of ground water. But, this may not be such a feasible method, more so in far flung villages where people will have to ultimately tap the ground water sources. So, it is of paramount importance that a simple, efficient and economically viable treatment technique should be developed for treating the drinking water in a domestic scale.
Most research has been directed at the control of arsenic pollution of potable water (Prasad, Gur (1994); Removal of Arsenic (v) from aqueous system by adsorption onto some geological materials. Arsenic in Environment, Part I, J.O. Nriagu(Ed.), John Wiley & sons, Inc.). A variety of methods have been used in the past for the arsenic removal from water and wastewater which include ion-exchange, complexation with ferric iron and coprecip-itation with metal hydroxide plus adsorption onto coagulant flock or onto other adsorbents. However, most of these methods describe the removal of a single species of arsenic separately and are also not very cost effective. Use of lime water softening process yielded 85% removal (Magnusen, L.M., Wough, T.C., Galle, O.K. and Bredfeldt, J. (1970); Arsenic in detergents, Science). Simple filtration through a charcoal bed yielded 70% removal (Magnusen, L.M., Wough, T.C., Galle, O.K. and Bredfeldt, J. (1970); Arsenic in detergents, Science ; Patterson, J.W. and Minar, R.A. (1973); Waste water Technology, 2nd Edn., Illinois Inst, for Environment Quality Document). Lee and Rosehart (Rosehart, R. and Lee, J. (1972); Effective methods for Arsenic Removal from Gold Mine Waste, Can mining J.) have reported 40% reduction of arsenite by activated carbon. Ion - exchange resins also appear effective in removing arsenate and arsenite but these are too costly. The treatment process development for arsenic removal making use of activated carbon (Huang, C.P. and Fu, P.L.K. (1982); Treatment of Arsenic (v) containing water by activated carbon process. 55th Annual Conf., W.P.C.F., St. Louis Missour) takes care of only As(V). Similarly, attempts to remove arsenic from aqueous system
by adsorption onto hematite and feldspar (Prasad, Gur (1994); Removal of Arsenic (v) from aqueous system by adsorption onto some geological materials. Arsenic in Environment, Part I, J.O. Nriagu(Ed.), John Wiley & sons, Inc.) were fruitful only for As(V). Removal of arsenic (pentavalent) from drinking water was achieved by the activated alumina system, treating the raw water at pH 5.5 (Hathaway, S.W. and Rubel, F.(Jr.)(1988); Removing Arsenic From Drinking Water. Journal of A.W.W.A.), not at drinking water pH (pH 6.5 - 8.5). Adsorption of arsenic (both As(III) and As(V) onto clay minerals, kiolinite and montmorillonite, has been studied by some workers (Frost, R.R. and Griffin, R.A. (1977) ,-Effect of pH on adsorption of Arsenic & Selenium From landfill leachate by clay minerals. Soil Sci. Am. J.). But this study has been done for leachate of these species by the minerals and not for the removal of arsenic from water. In all the above described methods, dependent on adsorption theory, a large amount of adsorbent is needed which is possible only in laboratory scale and is inconvenient for commercial use due to production of huge quantity of sludge.
Major treatment methods for arsenic removal employing precipitation technique include sulfide precipitation with addition of sodium or hydrogen sulfide (Curry, N.A. (1972);Philosophy & Methodology of Metallic Waste Treatment. 27th Purdue Industrial Waste Conf., Purdue University) which is partially effective for arsenate, but ineffective for arsenite (Rosehart, R. and Lee, J. (1972); Effective methods for Arsenic Removal from Gold Mine
Waste, Can mining J.). Other precipitating agents have also been used for arsenic removal such as, lime which is effective for both, arsenite and arsenate (Rosehart, R. and Lee, J. (1972); Effective methods for Arsenic Removal from Gold Mine Waste, Can mining J.) but at a higher pH ( > 11.0 ) and it is effective only in the presence of iron (Skripach, T.,Kagan,v., Ramanov, ML, Kamer, L. and Semina, A. (1971); Removal of Fluorine and Arsenic from the Waste Water of rare earth Industry. 5th Internat.Conf. Water Poll. Res.). Alum could be used for arsenic (pentavalent) removal but is less effective giving only 10-25 % removal (Logs-don, G.S., Sorg, T.J. and Symons, J.M. (1974);Removal of heavy metals by Conventional Treatment. 16th Water Quality Conf., University of Illinois Urbana, Illinois.) and doses are also high. When polyvalent metallic ions are introduced in the water samples, they react with the complex arsenic ions and are copre-cipitated at the pH of their hydroxide deposits (Patterson, J.W. and Minar, R.A. (1973); Waste water Technology, 2nd Edn., Illinois Inst, for Environment Quality Document.). Thus ferric chloride has been used for precipitation (Shen, Y.S. (1973); Study of Arsenic Removal from Drinking Water. J. of A.W.W.A.) giving good results with As(V) in the absence of any oxidising agent. Recent workers (Pande, S.P., Deshpande, L.S., Patni, P.M. and Lutade, S.L. (1997); Arsenic Removal Studies on Some Ground Waters of West Bengal, India. J. Environ. Sci. Hlth.) have used chlorine for oxidation followed by coagulation using ferric chloride. This method apart from being clumsy, is a two step process and the suggested dose is also high. Ferric sulfate along with alum has
also been used as coagulant and has given good results (Logsdon, G.S., Sorg, T.J. and Syraons, J.M. (1974)/Removal of heavy metals by Conventional Treatment. 16th Water Quality Conf., University of Illinois Urbana, Illinois.) but it is successful only in removing As(V). Ferrous sulfate can also precipitate arsenic but then again it can only remove pentavalent arsenic (Shabumin, I.I., Gutman, A.I. and Kogan, B.L. (1968); Removing Arsenic from sewage of Gold extraction Plants. Tsventnye Metally.; Rosehart, R. and Lee, J. (1972); Effective methods for Arsenic Removal from Gold Mine Waste, Can mining J.). Similar is the case with ferrous and ferric hydroxide precipitation (Viniegra, G., Marquez, R.E., Espinosa, M.B. and Caballero, P.J. (1964); Treatment of the Drinking Water.Salud. Publ. Mex. ; Gulledge, J.H. and 0 Connor, T.J. (1973); Removal of Arsenic (v) from water by Adsorption on Alumina and Ferric hydroxide. J. A.W.W.A.). Thus, in all these methods, described above, chemicals were used separately for adsorption or precipitation of either arsenite or arsenate and if used for both species, they have not given good results or have huge sludge yield or need high doses. While the composition of present invention can initiate different actions like oxidation, complexation, coprecipitation and adsorption followed by decolou-risation simultaneously at pH levels specified for drinking water
(pH 6.5 - 8.5), overcoming the previous shortcomings. So, also,
above 99% removal of arsenic is achieved.
The main object of the present invention is to provide a composition useful for the removal of arsenic from water. Another
Object is to provide capsule/tablets made from the said composition .Yet another object of the present invention is to provide a composition useful for removal of arsenic, both As(III) and As(V), from water which can be easily adopted in ordinary households.
Accordingly the present invention provides a process for preparation of a synergistic composition composition useful for removal of arsenic from water which comprises conventional mixing of complexing and coprecipitating agent (ferrous sulphate) 73% to 87%,oxidising agent (potassium permanganate) 9% to 18% and adsorbing agent ( activated charcoal) 4% to 10% .
In an embodiment of the present invention the complexing and co precipitating agent used is ferrous sulphate. In another embodiment oxidizing agent used is potassium permanganate.In yet another embodiment the adsorbing and de colourising agent used is activated charcoal.
Accordingly , the present invention provides a capsule/tablet made from the above composition by conventional methods.
The composition prepared is not a mere admixture resulting in mere aggregation of the properties of individual ingredients but is a synergistic mixture.
It is a small capsule, containing about 0.6 g of simple chemicals
like ferrous sulphate (FeSO 4. 7H20), potassium permanga
nate (KMn04) and activated charcoal in the ratio of 7.5:1.5:1 to 20:2:1 (+O.05) . The composition achieves the removal of arsenic by a process of oxidation, complexation, co-precipitation and adsorption followed by decolourisation simultaneously. The resulting precipitate can be removed by filtration (using clean cotton wool or a fine cloth or water filter candle). Here, one component of the composition i.e., potassium permanganate oxidises ferrous to ferric and arsenite to arsenate and then, arsenic forms a complex with iron and gets coprecipitated with its hydroxide. Thus, KMn04 acts as an oxidising agent as well as a disinfectant and activated charcoal acts as an adsorbent and decolourising material. In short, ferrous sulphate and potassium permanganate collectively precipitate arsenic and activated charcoal works as a good adsorbent. Hence, the efficiency of arsenic removal is enhanced.
The process is as follows, the contents of one capsule is added to about 10 litres of water containing upto about 0.3 ppm of arsenic and after stirring well with wooden or glass rod it is allowed to stand for about 45 minutes to 1 hour. Then, the water is filtered through clean cotton wool or a fine piece of cloth. Arsenic concentration in the filtered water falls below 0.005 ppm. This result has been found at normal conditions of pH and temperature of water. This composition must prove to be a boon to the villagers threatened with arsenic poisoning owing to its simplicity and low cost. Even the very poor can afford it. Care has to be taken in storing the capsules in airtight containers to prevent them from coming into contact with atmospheric moisture. Following examples are given by way of illustration therefore it should not for construed to the limit of the scope of present invention.

Example : 1
0.6g of said composition, FeS04.7H20, KMn04 and activeted charcoal in the ratio of 87% : 9% : 4% was added in 10 litres of water containing 0.3ppm arsenic, stirred well and filtered after one hour. In the filtrate the concentration of aresenic was estimated and was found 0.037ppm which is below permissible limit. The removal was 87%.
Example 2 0.6g of said composition, FeS04.7H20, KMn04 and activeted charcoal in the ratio of 75% : 15% : 10% was added in 10 litres of water containing 0.3ppm arsenic, stirred well and filtered after one hour. In the filtrate, the concentration of aresenic was estimated and was found 0.006ppm which is below permissible limit. The removal was 98%.
Example 3
0.6g of said composition, FeS04.7H20, KMn04 and activeted charcoal in the ratio of 73% : 18% : 9% was added in 10 litres of water containing 0.3ppm arsenic, stirred well and filtered after one hour. In the filtrate the concentration of aresenic could not be detected upto 0.005ppm which is below permissible limit. The removal was more than 99%.
The main advantages of the present invention
(1) The Composition of the present invention can be used for the removal of both species i.e. arsenite and arsenate from water
(2) The composition acts as a disinfectant.
(3) The composition acts as a decolourising mixture. (4) The composition is very easy to use.





We claim :
l. A process for preparation of a synergistic composition useful for the removal of arsenic from water which comprises conventional mixing of complexing and coprecipitating agent 73% to 87%,oxidising agent 9% to 18% and adsorbing agent 4% to 10%.
2.A process for preparation of a synergistic composition as claimed
in claim 1 wherein complexing and co precipitating agent used is
ferrous sulphate.
3. A process for preparation of a synergistic composition as claimed in
claim 1-2 wherein oxidizing agent used is potassium permanganate.
4. A process for preparation of a synergistic composition as claimed in claim 1-3 wherein adsorbing decolourising agent used is activated charcoal.
5. A process for preparation of a synergistic composition useful for the removal of arsenic from water substantially as herein described with reference to the examples.

Documents:

1115-del-1998-abstract.pdf

1115-del-1998-claims.pdf

1115-del-1998-complete specification [granted].pdf

1115-del-1998-correspondence-others.pdf

1115-del-1998-correspondence-po.pdf

1115-del-1998-description (complete).pdf

1115-del-1998-form-1.pdf

1115-del-1998-form-2.pdf

1115-del-1998-form-4.pdf


Patent Number 188959
Indian Patent Application Number 1115/DEL/1998
PG Journal Number 48/2002
Publication Date 30-Nov-2002
Grant Date 19-Sep-2003
Date of Filing 27-Apr-1998
Name of Patentee COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 DHIRENDRA BAHADUR SINGH CENTRAL MINING RESEARCH INSTITUTE, DHANBAD-826001, INDIA.
2 BHARAT BHUSHAN DHAR CENTRAL MINING RESEARCH INSTITUTE, DHANBAD-826001, INDIA.
3 KARUVAPATTY CHAMIYER JAYAPRAKAS CENTRAL MINING RESEARCH INSTITUTE, DHANBAD-826001, INDIA.
PCT International Classification Number CO2F 5/000
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA