Efficient removal of tetracycline hydrochloride from aqueous solution by mesoporous cage MOF-818

Abstract

MOF-818, a mesoporous cage metal–organic framework, was investigated for the removal of tetracycline hydrochloride (TC) from aqueous environment. The product was characterized by XRD, BET, FESEM, FT-IR, XPS and TGA. The influence of different parameters such as solution pH, contact time, temperature, adsorption dosage, initial TC concentration on the adsorption capacity was investigated. The as-prepared MOF-818 showed rapid removal of TC and with maximum saturated adsorption capacity calculated to be 442.5 mg g−1 at pH 3.32, 323 K. The adsorption isotherms were fitted by Langmuir, and Freundlich models. The kinetic data was analyzed by pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The TC adsorption process followed pseudo-second-order kinetics and best fitted the Langmuir adsorption model. The thermodynamic data showed that the adsorption was a spontaneous and endothermic reaction. A mechanism for TC adsorption was proposed and the chemisorption and π–π interaction was believed to direct the interaction between MOF-818 and TC molecules.