Removal of methylene blue from simulated wastewater by Carica papaya wood biosorbent

Abstract

In this study, batch and continuous-flow sorption experiments were conducted to evaluate the removal of methylene blue (MB) from aqueous solutions by Carica papaya wood (CPW) biosorbents. The effects of critical factors such as initial pH, particle size of the biosorbent, biosorbent dosage, initial dye concentration, contact time, and salt ionic strength were studied in batch experiments. The equilibrium data fit well to the Langmuir isotherm model with the highest monolayer adsorption capacity of 63.29 mg/g at an initial dye concentration of 50 mg/l, pH of 10, and contact time of 60 min. Batch desorption and regeneration studies using 0.1 M HCl as the desorbing agent indicated that the removal efficiency of MB lasted up to 5 cycles. Continuous-flow biosorption experiments were investigated to determine the practical applicability of the biosorbent. The dye removal efficiency increased with an increase in absorbent dosage and decreased with an increase in flow rate. The Thomas model was found to be in good agreement with all the experimental data collected from continuous flow sorption. It was concluded that this study presented CPW as a promising biosorbent material for the removal MB from aqueous solutions.

Keywords

• biosorption
• Carica papaya wood
• desorption
• methylene blue