CADMIUM REMOVAL FROM WATER ENVIRONMENT BY A FUNGUS VOLVERIELLA-VOLVACEA

Biosorption technique was used for removal of cadmium under different conditions from water environment using a biosorbent, Volveriella volv aceas, locally growing fruit bodies of mushroom. Effects of different parameters like pH, sorbent concentration, ionic strength on the remov al efficiency of cadmium by V. volvacea were carried out in continuati on with adsorption kinetics and equilibrium isotherm experiments. From the kinetics studies it was found that nearly 95% of the total cadmiu m removal was achieved from cadmium spiked distilled water within firs t 15 minutes. Isotherm data was best fitted to linearised Langmuir equ ation and the sorption capacity was found to be varying from 9.13 to 9 .33 mg/g for different sizes of sorbent. The uptake of cadmium(II) is a function of pH of the solution and increases with the increasing pH. Increasing ionic strength and the presence of soluble complexing agen ts such as ethylene diamine tetraacetic acid (EDTA) decrease the sorpt ion of cadmium(II). The presence of other diavalent cations like calci um and magnesium impedes the uptake of cadmium(II). The presence of ch loride ion has no significant effect on cadmium(II) removal. The spent biosorbent can effectively be regenerated with acid and can then be r eused.