Removal of methylene blue from aqueous solution by ceramsite filter media combined with high temperature calcination for regeneration

摘要

Ceramsite, made of municipal waste, was prepared by high-temperature sintering process. Ceramsite was utilized as a filter media for the removal methylene blue (MB) from aqueous solution and was regenerated by high temperature calcination. The batch studies results showed that the equilibrium isotherms and adsorption kinetics of MB adsorption on ceramsite filter media (CFM) were described better by the Langmuir model and pseudo-first-order kinetics than by the Freundlich model and pseudo-second-order kinetics, respectively. Under the CFM bed column operating conditions of the MB initial concentration of 5 mg L-1, particle size of 0.5 +/- 0.2 mm and flow rate of 1 mL min(-1), the breakthrough data were agreed well with the bed depth service time (BDST) model at 15% and 50% breakthrough for MB. The regeneration tests proved that high-temperature calcination was an effective regeneration method for the recovery of exhausted CFM. Both the adsorption kinetics of MB on CFM and regenerated CFM (in a certain cycle range) were found to match the Thomas model; whereas, the maximum adsorption capacity of CFM decreased slightly with the increase in regeneration cycles.