A composite mesoporous ceramsite derived from activated carbon and attapulgite clay for efficient removal of methylene blue from aqueous solution

The adsorptive removal of methylene blue (MB) from aqueous solution is often executed by attapulgite (ATP) due to its unique one-dimensional nanoscale structure and low-cost, abundant, eco-friendly advantages. Another commonly used material for this job is activated carbon. In this study, a novel composite porous ceramsite was prepared by combining activated carbon and ATP clay to remove MB from an aqueous solution. The composite porous ceramsite, calcined at 450 °C (CPC-450), was characterized by SEM, FT-IR, XRD, and BET specific surface area measurements. It possessed a high specific surface area of 313.606 m 2 /g and exhibited superior adsorption capacity toward MB than that of raw ATP. Consequently, a 99.6% MB removal efficiency was achieved at adsorption equilibrium. Moreover, the maximum adsorption capacity of CPC-450 increased compared to the raw ATP, with a value of 50.68 mg/g, and it could be reused more than 6 times. The adsorption experiment was executed at different conditions, and the Langmuir isotherm model and pseudo-second-order kinetic equation fitted the obtained data very well. The main driving forces for the adsorption process were found to be hydrogen-bonding interaction, electrostatic attraction, and chemical association.