Biochar prepared from co-pyrolysis of municipal sewage sludge and tea waste for the adsorption of methylene blue from aqueous solutions: Kinetics, isotherm, thermodynamic and mechanism

A rise in operating temperature enhances MB adsorption on biochar. Adsorption thermodynamic of MB on biochar showed that the adsorption was a spontaneous and endothermic process and revealed favorable spontaneous under higher temperature conditions. Meanwhile, the positive values of ∆ S suggest the increased randomness at the solid/solution interface during the sorption of MB onto biochar. The mechanism between MB and biochar involved electrostatic interaction, ion exchange, surface complexation, physical function and others. This work shows that the biochar hold promises acting as effective adsorbent to remove dyes in the wastewater.