The objective of the present work was to study biosorption of mercury, cadmium, lead and hexavalent chromium by waste fungal materials (Penicillium oxalicum var. Armeniaca, Tolypocladium sp.) produced by Czech fermentation industry. Strong alkaline treatment of Penicillium biomass gave an efficient sorbent (called P3 sample), while biomass of Tolypocladium (referred as T sample) was used as supplied. At first, their sorption properties have been checked for metal recovery from monometallic synthetic solutions. The best sorption of cationic species was observed at pH close to neutrality, while chromium was better removed from acidic solutions (pH 2-3). Regarding maximum sorption capacities (derived from sorption isotherms) biosorbent P3 clearly showed higher capacity than biosorbent T for each individual metal. The maximum sorption capacities at optimum experimental conditions may reach 270 mg Hg g-1 sample P3 (pH 5), 160 mg Hg g-1 sample T (pH 7), 70 mg Cr(VI) g-1 sample P3 (pH 3) and 55 mg Cr(VI) g-1 sample T (pH 2). These values are on the upper boundary of the ranger reported in the literature. On the contrary the sorption capacities obtained for cadmium and lead were less favourable. The process followed second-order reaction kinetics and the influence of diffusion phenomena on the transport rates in suspensions was discussed. It was proved that nitrogen containing groups played an important role in biosorption mechanisms of P3 sorbent. Cations were removed by chelation at pH close to neutrality, while hexavalent chromium was sequestered by the electrostatic attraction to the protonated groups at acidic pH. In the case of T sample, the participation of carboxyl groups in the removal was observed and ion exchange mechanism was suggested. Concerning hexavalent chromium a combined process of sorption/reduction was reported, but the exact mechanism was not found. Sorption from synthetic bimetallic solutions was tested further, while the selectivity of P3 sorbent for mercury was confirmed. The competitive behaviour was only observed in case Hg-Cd system using T sample. Finally, the dynamic sorption in a fixed bed column system was studied using Tolypocladium beads (immobilized on infusorial earth). The column sorption was controlled by intraparticular diffusion. Influence of two parameters was tested; increasing inlet concentration and particle size led to a decrease of the column service time.
