Bone meal and chitosan biocomposite: a new biosorbent for the removal of Victoria Blue R from wastewater

Abstract

Chitosan immobilized bone meal (CIBM) was prepared as a biosorbent and Victoria Blue R (VBR) textile dyestuff was removed from wastewater using CIBM via biosorption. For this purpose; the effect of pH, contact time, ionic strength, temperature, biosorbent amount, and initial sorbate concentration were studied in the batch system. The specific surface area, surface morphology and functional groups of CIBM were characterized using BET, SEM and FTIR techniques. In the preliminary biosorption studies with pure bone meal, the removal yield of VBR from solutions of 25 mg/L VBR prepared in pure water was found to be 40.32%, while after modification with chitosan, a removal yield of 98.69% was achieved. As a result, it was observed that the biosorption efficiency increased significantly via modification. The biosorption equilibrium was set at the original pH of the dye with a biosorbent amount of 3.00 g/L in 15 min., which are the optimum adsorption parameters of the batch biosorption process. The removal of VBR from real wastewater was investigated, and the efficiency was found to be 90.40%. Biosorption-desorption cycle was investigated for 11 cycles, and CIBM almost maintained its biosorption capacity until the ninth cycle. Kinetic, isotherm and thermodynamic models were used to analyze the data obtained from the experiments. As kinetic models, pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models were used along with the intraparticle diffusion model. For isotherm models, Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models were employed. It was determined that the experimental biosorption data obey the second-order kinetic model.