Dried activated sludge as an appropriate biosorbent for removal of copper (II) ions

Removal of Cu (II) from aqueous solution by dried activated sludge (DAS) was investigated. Batch process for the biosorption of Cu (II) ions was performed to determine equilibrium and adsorption characteristics of DAS. Obtained results by scanning electron microscope showed DAS pretreated with 1% H2O2 was porous and also it had effective removal for Cu (II) ions from aqueous solutions. Effects of contact time, temperature, pH and DAS dosage on the biosorption of Cu (II) were studied. The maximum biosorption of Cu (II) at temperature of 20 °C and pH of 5 was obtained (85%) with the DAS dosage of 3.5 g/L, Cu (II) ion concentration of 100 mg/L and 4 h contact time. Also removal efficiency of Cu (II) decreased with increasing temperature. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were employed to study biosorption isotherms for removal of Cu (II). Weber–Morris, pseudo first order and pseudo second order models were applied to describe the biosorption kinetics.