Improvement of heavy metal biosorption by mycelial dead biomasses (Rhizopus arrhizus, Mucor miehei and Penicillium chrysogenum): pH control and cationic activation

摘要: Abstract Fungal mycelial by-products from fermentation industries present a considerable affinity for soluble metal ions (e.g. Zn, Cd, Ni, Pb, Cr, Ag) and could be used in biosorption processes purification of contaminated effluents. In this work the influence pH on sorption parameters is characterized by measuring isotherms five heavy metals (Ni, Ag Pb) with Rhizopus arrhizus biomass under pH-controlled conditions. The maximum capacity lead was observed at 7.0 (200 mg g -l ), while silver uptake weakly affected. stability metal-biosorbent complexes regularly enhanced neutralization, except lead. A transition mechanism above 6.0. addition, comparison various industrial fungal biomasses ( R. arrhizus, Mucor miehei Penicillium chrysogenum indicated important variations zinc-binding buffering properties (0.24, 0.08 0.05 mmol −l , respectively). Without control, equilibrium (5.8, 3.9 4.0) shown to related initial calcium content biosorbent, neutralization during adsorption increases zinc all fungi (0.57, 0.52 0.33 g-l) but an improvement also obtained (0.34, 0.10 −1 ) saturation before accumulation. Breakthrough curves fixed bed biosorbent columns demonstrated process purify solutions continuous-flow systems, confirmed necessity cationic activation contact heavy-metal solution.