Effect of different conditions on Cu(II) and Cr(VI) biosorption by dried waste tea fungal biomass

Some industrial wastewaters contain high quantities of non-toxic salts besides heavy metal ions. The presence of salt ions leads to a high ionic strength of water, which may significantly affect the performance of the biosorption process, so that the effect of salts on the biosorption of heavy metal ions should be investigated. In this study the effect of different salts concentrations (0.1; 0.5 and 1 mol L-1) and dosage of tea fungal biomass (0.15; 0.25 and 0.5 g L-1) dried at different temperatures: 20°C, 70°C, 80°C, 105°C and 125°C on Cu(II) and Cr(VI) biosorption was studied in a batch system. Biosorption at an ionic strength of 0.1 mol L-1 of all salts investigated had a decreasing effect on Cu(II) and Cr(VI) removal. It was observed that (NH4)2SO4 at the concentrations of 0.5 mol L-1 and 1 mol L-1 was more efficient than other salts for metal ions removal. In case of Cr(VI) the most efficient removal was obtained for the water with K2SO4 at a concentration of 0.5 mol L-1. The lowest biosorbent dosage (0.15 g L-1 tea fungal biomass dried at 20°C in the case of Cu(II) biosorption and at 80°C in the case of Cr(VI) biosorption) resulted in the highest metal uptake of 38 mg g-1 in case of Cu(II) and 33 mg g-1 in case of Cr(VI)