Title of Invention	"A NOVEL CATALYST USEFUL FOR CONTROLLING MICROORGANISM IN WATER AND A PROCESS FOR THE PREPARATION THEREOF"
Abstract	The present invention relates to a process for the preparation of highly active silver deposited on carbon covered alumina catalyst, in controlling the microorganism in water.

Full Text

Field of the invention The present invention relates to a process for the preparation of highly active silver deposited on carbon covered alumina catalyst, in controlling the microorganism in water. Background of the invention Most of the diseases are spreading because of the poor quality of water, which is one of the most essential elements for the survival of living beings, particularly because of the presence of bacteria and viruses in the water. Hence it is utmost important to purify the water before its use. There are several methods of water purification like chlorination, iodination, ozonation, UV-purification, reverse osmosis and silver ions. Chemical purification like addition of chlorine, iodine or ozone has several disadvantages. For example, excess chlorination leads to cancer. Other methods like UV-purification and reverse osmosis are not cost effective. Ever since silver has been recognized as a bactericide, its application in purification of water is increasing. The present invention provides a process for the preparation of silver deposited on carbon covered alumina and its ability in controlling the microorganism in water. The ability of silver in water purification was disclosed in a US patent 4,608,247 wherein silver micro crystals on (X-AI2O3 with a copper sheath surrounding it has a capability of Ag and Cu to leach into the swimming pool by galvanic action without application of electric current. A US patent 6758345 discloses treatment medium comprising silver deposited on to an alumina substrate useful for controlling microorganism in water effectively. Another US patent discloses silver and a second metal say Pd co-deposited on alumina as an effective catalyst in controlling the microorganism in water. Another co-pending Indian patent application 1055/DEL/03 discloses a process of making silver on activated carbon by in-situ deposition using low voltage current for controlling microorganism in water. The main drawbacks of the above mentioned patents is that alumina reacts with various impurities in water on contact for a long time because of its acidic character and also activated carbon is not a high strength material. Moreover in activated carbon the micro pores are not accessible for depositing silver ions. However both these supports alumina and carbon have advantages like high mechanical strength possessed by alumina and high inertness of carbon towards various impurities present in water. Also carbon is known to be deodorizer and decolorizing agent. Objectives of the invention The main objective of the present invention is therefore to utilize the combined characteristics of alumina and carbon as a support by depositing silver on carbon covered alumina. Yet another objective of the invention is to provide a process wherein the silver content in the catalyst is in the range of 0.1 to 10 weight percent preferably 1 to 5 weight percent Still another objective of the invention is to provide a process for controlling the microorganism present in water. Summary of the invention Accordingly the present invention provides a novel catalyst useful for controlling the microorganism in water comprising silver deposited on carbon covered alumina catalyst. In an embodiment of the present invention the catalyst has a silver content in the range of 0.1-10 Wt% In yet another embodiment the catalyst has a silver content preferably in the range of 1-5 Wt%. The present invention further provides a process for the preparation of a catalyst useful for controlling the microorganism in water which comprises depositing the silver on carbon covered alumina either by an impregnating method or an electrochemical method. In an embodiment the present invention further comprises impregnating silver on carbon covered alumina by stirring as aqueous solution mixture of silver nitrate and carbon covered alumina for a period of 0.5-3 hrs, evaporating the solvent and drying the resultant product in a hot air oven for an over night period, reducing the above said dried product in a flow of hydrogen, at a temperature in the range of 150 -400°C, for a period of 2-5 hrs to obtain the desired product. In yet another embodiment the temperature used is preferably in the range of 200-300°C. In yet another embodiment the process further comprises electrochemically depositing silver nano particles over carbon covered alumina by passing a DC power of about 40V through a pair of silver electrodes in an aqueous solution, under stirring for a period of 8-15 hrs, evaporating the water solvent to dryness followed by drying the resultant catalyst in an air oven to obtain the desired product. In yet another embodiment the catalyst obtained has a silver content in the range of 0.1-10 Wt%. In yet another embodiment the catalyst obtained is 100% microbial active after about 1 hr of contact with microorganism in water. Detailed Description of the Invention In our continuous intensive research and experimental studies we found that both silver deposited on carbon and silver deposited on alumina are effective in controlling microorganism in water. The objective of the present invention is to provide a process to utilize the combined characteristics of alumina and carbon in the form of carbon covered alumina, which acts as a support for silver and the ability of the material in controlling the microorganism in water. An embodiment of the present invention is a process for making silver deposited on carbon covered alumina support. Other embodiment of the present invention is a process wherein the silver content in the catalyst is in the range of 0.1 to 10 weight percent preferably in the range of 1 to 5 weight percent. Another embodiment of the present invention is a process wherein the ability of silver deposited on carbon-covered alumina in controlling microorganism in water is disclosed. Micro crystals of silver have a tendency to lightly bound nascent oxygen (with a binding energy of only 40 kcal/mol) and these species readily oxidize bacteria or viruses, resulting in complete disintegration. Among all the metals, silve- is unique in its affinity towards oxygen. It was reported that atomic oxygen had an almost perfect fit in the octahedral holes of gold, silver and copper. However, in gold the electron cloud of oxygen tends to be expelled by lattice oxygen of gold atoms and this block the movement through holes. Copper, on the other hand forms the oxide providing an impossible barrier. Silver offers so little repulsion to oxygen that only a small amount of thermal energy is required to readily move the atomic oxygen through the silver lattice. The atomic oxygen adsorbed on to the surface of silver exposed to aqueous media readily reacts with pairs of sulfhydril (-S-H) groups on the surface of the bacteria or viruses by replacing the hydrogen atoms (as water) resulting in the coupling of the sulfur atoms to form -R-S-S-R- bond which completely blocks the respiration process and electron transfer. Monovalent silver ions have an affinity for sulfhydril groups exposed on bacteria or viruses. The combined characteristics of carbon and alumina can be achieved by making carbon covered alumina by a standard procedure i.e., by pyrolysis of hydrocarbon on alumina. Even though the carbon thus deposited on alumina is pyrolytic in nature it covers most of the surface acidic sites of alumina (Ref: Applied Catalysis A: General, 83 (1992) 141). Moreover, the carbon coverage on alumina prevents alumina to contact with the impurities present in water. Silver can be deposited on carbon-covered alumina by standard impregnation technique or by electro deposition method. In electrochemical method, the run time has been varied to get silver (with variable particle size) [Ref. J. Mol. Catal. A: Chemical 223 (2004) 313]. This methodology has been applied to get silver with variable composition. Raw water that is to be analyzed is taken and it is serially diluted in a series of test tubes. From each test tube 0.1 ml of the water is taken and is spread on the petri-plates using a spreader containing solidified nutrient agar and are incubated at 37 °C for 24 h. This entire process is done in the laminar air flow. The numbers of colonies grown are then counted after incubation. The ability of the catalyst in controlling microorganism in water is done after vigorous stirring of about 50 ml of raw water with the catalyst taken and filtering off the catalyst followed by the above procedure to get the number of colonies. Nutrient agar solution is prepared by dissolving 28 g in 1000 ml of distilled water and is autoclaved at a pressure of 15 lbs for around 15 min. Then after cooling it is distributed in 36 petri-plates with 5 ml in each petri-plate and left for solidification. Saline water is prepared by dissolving 2.88 g of NaCI in 300 ml of distilled water. This saline solution is distributed in 30 test tubes with each one containing 9ml of it, covered with cotton plugs and autoclaved at a pressure of 15 lbs for 15 min. They are then cooled and inoculated with 0.1 ml of the inoculated culture and the mixture is spread on the agar petri-plates for quantification of microorganisms. The present invention is described with reference to the following examples that are explained by way of illustrations only and should not therefore be construed to limit the scope of the present work. Example -1 To 10 ml aqueous solution containing 79 mg of silver nitrate, 5 g of dried carbon covered alumina is added and kept for stirring for 1 hour followed by removing the excess water by evaporating on a hot plate with stirring and drying in a hot air over for over night. The dried samples are then reduced in a flow of hydrogen at 250 °C for 3h. The catalyst sample thus prepared contains 1 weight percent of silver and is denoted as Ag-CCA-1 (I). The catalyst samples with 2 and 4 wt. % are also prepared in a similar way by adding 158 mg and 316 mg of silver nitrate and designated as Ag-CCA-2 (I) and Ag-CCA-3 (I) respectively. Example - 2 5 g of carbon-covered alumina has been immersed in 2 lit. distilled water and silver nano-particles are generated by passing a 40 V DC power through a pair of silver electrodes (0.4mm thickness and 10mm width and 150mm long plates) while maintaining a constant rapid stirring for 10h. The water is evaporated to dryness on a hot plate with stirring and the resultant catalyst is dried in an air oven for over night. The resultant catalyst contains 2 weight percent of silver and is denoted as Ag-CCA (EC). Example - 3 To a 50 ml of water containing coli forms, Ag-CCA(I) catalyst as mentioned in example - 1, is added and stirred well for 1 h, followed by filtration to remove the catalyst particles. 1ml of the filtrate water that is to be analyzed is taken in a test tube containing 9ml of saline water and it is serially diluted in a series of 6 test tubes each containing 9 ml of saline water. Similarly, 1 ml of the raw water is taken in the first test tube containing 9 ml of saline solution and from it 1 ml is taken into the second test tube also containing 9 ml of saline solution. This process is repeated to 6 times from each test tube, 0.1 ml of the water is taken and is spread on the petri-plates using a spreader containing solidified nutrient agar and are incubated at 37 °C for 24 h. This entire process is done in the laminar air flow. The number of colonies grown is then counted after incubation. The ability of Ag-CCA-2 (I) in controlling the microorganism is shown in Table - 1. Table - 1: Performance of Ag-CCA(I) catalyst in controlling microorganism in water (Table Removed) Example - 4 To a 50 ml of water containing coli forms, Ag-CCA(EC) catalyst, as mentioned in example - 2 is added and stirred well for 1 h, followed by filtration to remove the catalyst particles. 1ml of the filtrate water that is to be analyzed is taken in a test tube containing 9 ml of saline water and it is serially diluted in a series of 6 test tubes each containing 9 ml of saline water. Similarly, 1 ml of the raw water is taken in the first test tube containing 9 ml of saline solution and from it 1 ml is taken into the second test tube also containing 9 ml of saline solution. This process is repeated to 6 times. From each test tube 0.1 ml of the water is taken and is spread on the petri-plates using a spreader containing solidified nutrient agar and are incubated at 37 °C for 24 h. This entire process is done in the laminar airflow. The number of colonies grown is then counted after incubation. The number of colonies grown is then counted after incubation. The ability of Ag-CCA(EC) in controlling the microorganism is shown in Table - 2. Table - 2: Performance of Ag-CCA(EC) catalyst in controlling microorganism in water (Table Removed) Example-5 To a 50 ml of raw water (containing coli forms or bacteria) sample taken in a clean sterilized beaker, about 1 g of Ag-CCA(I) catalyst as mentioned in example-1 is added and kept for one hour with constant stirring. The catalyst particles are then separated by filtration and the water is collected into a sterile, transparent 100ml vessel with screw cap, and the granules of the Ready cult coli forms reagent (supplied by E.Merck, Germany) is added by breaking the snap pack. The vessel is sealed and shaken to completely dissolve the granules and incubated for about 24 hours at 31 OK. The broth remained slightly yellow (no colour change); it is an indication of absence of total coli forms. It is an indication that the total coli forms are killed with the action of silver particles on the CCA catalyst. Table - 3: Effect of Ag loading on the control of micro organism. (Table Removed) We claim 1. A novel catalyst useful for controlling the microorganism in water comprising silver deposited on carbon covered alumina catalyst. 2. A catalyst as claimed in claim 1 has a silver content in the range of 0.1-10 Wt% 3. A catalyst as claimed in claim 1 has a silver content preferably in the range of 1-5 Wt%. 4. A process for the preparation of a catalyst useful for controlling the microorganism in water which comprises depositing the silver on carbon covered alumina by either an impregnating method or an electrochemical method. 5. A process as claimed in claim 4, further comprises impregnating silver on carbon covered alumina by stirring as aqueous solution mixture of silver nitrate and carbon covered alumina for a period of 0.5-3 hrs, evaporating the solvent and drying the resultant product in a hot air oven for an over night period, reducing the above said dried product in a flow of hydrogen, at a temperature in the range of 150 -400°C, for a period of 2-5 hrs to obtain the desired product. 6. A process as claimed in claim 5, wherein the temperature used is preferably in the range of 200-300°C. 7. A process as claimed in claim 4, further comprises electrochemically depositing silver nano particles over carbon covered alumina by passing a DC power of about 40V through a pair of silver electrodes in an aqueous solution, under stirring for a period of 8-15 hrs, evaporating the water solvent to dryness followed by drying the resultant catalyst in an air oven to obtain the desired product. 8. A process as claimed in claims 4-7, wherein the catalyst obtained has a silver content in the range of 0.1-10 Wt%. 9. A process as claimed in claims 4-8, wherein the catalyst obtained is 100% microbial active after about 1 hr of contact with microorganism in water. 10. A novel catalyst useful for controlling the microorganism in water and a process for the preparation thereof, substantially as herein described with reference to the examples.

Documents:

795-del-2005-abstract.pdf

795-del-2005-claims.pdf

795-del-2005-Correspondence Others-(13-05-2013).pdf

795-del-2005-Correspondence Others-(18-01-2013).pdf

795-del-2005-Correspondence-Others-(21-06-2013).pdf

795-del-2005-correspondence-others.pdf

795-del-2005-description (complete).pdf

795-del-2005-form-1.pdf

795-del-2005-form-18.pdf

795-del-2005-form-2.pdf

795-del-2005-Form-3-(13-05-2013).pdf

795-del-2005-Form-3-(18-01-2013).pdf

795-del-2005-Form-3-(21-06-2013).pdf

795-del-2005-form-3.pdf

795-del-2005-Form-5-(21-06-2013).pdf

795-del-2005-Petition-137-(13-05-2013).pdf