Cadmium, lead and mercury biosorption on waste fungal biomass issued from fermentation industry. I. Equilibrium studies

Two kinds of waste biomass (Penicillium oxalicum var. Armeniaca, Tolypocladium sp.) used in fermentation industry were submitted to different treatments and were tested as biosorbents of cadmium, lead and mercury. The study was initially focused on the evaluation of the impact of pH on the sorption of selected metals and continued with the sorption isotherms determination. The sorption capacities for the target metals can be ranked according to Hg ≫ Pb > Cd for P. oxalicum sorbent and Hg ≫ Cd > Pb for Tolypocladium sp. sorbent. P. oxalicum shows greater sorption capacities (based on sorption capacities in molar units) than Tolypocladium sp. Maximum sorption capacity as high as 270 mg Hg g−1 (initial pH 5, equilibrium pH close to 6.2) has been obtained for Penicillium derived biosorbent. The Langmuir isotherm equation fits significantly better experimental data than the Freundlich isotherm equation. FT-IR spectra and elemental analysis of the biosorbents have shown significant changes in their composition according to the treatment.