Process for preparing immobilized nano-sized metal particles

Abstract

The present invention provides a new process using biological method for the preparation of immobilized nano-particles of metals. Fungi are used to efficiently prepare immobilized nano-particles of various metals ions such as Au, Ag, Pd, Pt, Ni, Rh and Ru from their aqueous solutions.

We claim:  
     
         1 . A process for preparing immobilized nano-sized metal particles comprising treating wet fungal mycelia with a metal ion solution at temperature in the range of 15 to 40° C. for a period in the range of 2 to 120 hours, separating the biomass to obtain the immobilized nano-sized metal particles deposited on to the surface of the fungal cells.  
     
     
         2 . A process as claimed in  claim 1  wherein the wet fungal mycelia is obtained by growing the Verticillium (AAT-TS-4) in a culture medium for a period of 2 to 120 hours at temperature ranging between 15-40° C. under aseptic conditions, separating the biomass by centrifugation, washing several times with sterile water, and then incubating the whole reaction mixture at 15 to 40° C. and atmospheric pressure.  
     
     
         3 . A process as claimed in  claim 1  wherein the metal ion solution is obtained by dissolving metal salts of group IB-VIIIB metals in water  
     
     
         4 . A process as claimed in  claim 3  wherein the metal is selected from the group consisting of Au, Ag, Pd, Pt, Ni, Rh and Ru.  
     
     
         5 . A process as claimed in  claim 3  wherein the metal salts are selected from the group consisting of halides, nitrates and carbonates.  
     
     
         6 . A process as claimed in  claim 1  wherein the metal ion solution is obtained by dissolving the acidic form of metals in water.  
     
     
         7 . A process as claimed in  claim 6  wherein the acidic form of the metal is selected from chloroauric acid and chloroplatinic acid.  
     
     
         8 . A process as claimed in  claim 1  wherein the concentration of metal ions per gram of wet fungal mycelia is in the range of 10 to 200 mg metal ions per gram of wet fungal mycelia.  
     
     
         9 . A process as claimed in  claim 8  wherein the concentration of metal ions per gram of wet fungal mycelia is in the range of 10 to 100 mg metal ions per gram of wet fungal mycelia.  
     
     
         10 . A process as claimed in  claim 8  wherein the concentration of metal ions per gram of wet fungal mycelia is in the range of 25 to 100 mg metal ions per gram of wet fungal mycelia.  
     
     
         11 . A process as claimed in  claim 1  wherein the ratio of water to wet fungal mycelia is 100:1 (w/w).  
     
     
         12 . A process as claimed in  claim 1  wherein the fungus Verticillium AAT-TS-4 is taken as whole cell as wet solid mass.  
     
     
         13 . A process as claimed in  claim 1  wherein the reaction of the fungus and metal ion source in solution is carried out in water.  
     
     
         14 . A process as claimed in  claim 1  wherein the incubation/reaction temperature is in the range of 15-40° C.  
     
     
         15 . A process as claimed in  claim 14  wherein the incubation/reaction temperature is in the range of 23-33° C.  
     
     
         16 . A process as claimed in  claim 14  wherein the incubation/reaction temperature is in the range of 25-29° C.