High temperature synthesis of interfacial functionalized carboxylate mesoporous TiO2 for effective adsorption of cationic dyes

This study reported a facile method to enhance the adsorption capacity of TiO2-based mesoporous material for the removal of methylene blue (MB) as a cationic dye from aqueous solution. The mesoporous surface of the modified TiO2 was successfully grafted with interfacial carboxylate groups by using the sol-gel method with ethylenediaminetetraacetic acid (EDTA) as a template at high temperature. Properties of the as-synthesized adsorbents were characterized by FTIR, XPS, FE-SEM, TGA and BET analysis. The MB uptake by adsorption was highly dependent on the electrostatic interaction between the adsorbent and the adsorbate. Basic media was favorable for greater MB deposition on the modified TiO2 surface, which related to uncoordinated carbonyl groups. The maximum capacity was reported as 32.15 mg/L. The removal efficiency was maintained at 83% even after 9 adsorption-desorption cycles, which supported the reusability of the adsorbent for cationic dyes removal from aqueous solutions.