Synthesis, Characterization and Application of Nanoparticles of Sulfide of Zn2+, Cd2+ and Hg2+ ions by Using Biogenic and Chemical Route

The preparation of nanoparticles of Zn2+, Cd2+ and Hg2+ has been carried out by chemical and biochemical route using solvothermal method in presence of reducing solvent, ethylene glycol. In biochemical route, the fungus Aspergilus niger has been used. This reduces SO42- ion to S- forming ZnS, CdS and HgS nanoparticles extracellularly. Electrical conductivity experiment shows a voltage of 6.6mV and a current of 0.18A. UV- Visible spectra show charge transfer bands at 354nm due to electron transfer between M (d10 s0) (3p4), in delocalized band. IR spectrum of the nanoparticles ZnS, CdS and HgS in ethylene glycol by chemical route and by biochemical route shows C - H band which was affected in biochemical route from chemical route. The IR spectrum of ZnS in toluene shows the surface modification by formation of stable nanoparticles which clearly indicates the stability by existence of sharp splitting at 3852, 3733 cm-1 instead of broad band at 3400 cm-1 in ethylene glycol by biochemical route. Similar results have been observed for CdS and HgS in ethylene glycol and toluene solvent respectively. The alkane thiol stabilized nanoparticles transferred to assemble toluene phase obtained is as closed packed hexagonal array shown in X- ray diffraction pattern by evaporation of toluene. TEM show appearance of nanoparticles of ZnS, CdS and HgS in the range 10 to 20nm.