Zero valent iron particles impregnated zeolite X composites for adsorption of tetracycline in aquatic environment

Various weight percentages of zero valent iron particles (NZVI) were impregnated into the framework of zeolite X to synthesize a series of novel magnetic zeolites (n)FeX. The (n)FeX composites were applied to remove cationic tetracycline antibiotic (TC) from water. The result showed as the weight percentage of NZVI increased, some aluminums in the framework of zeolite X were substituted by irons for making the number of sodium ions increased and some NZVI were coated on the surface of zeolite X. The TC removal efficiencies of (n)FeX samples were increased as the weight percentage of NZVI increased. As the weight percentage of NZVI was 5%, the TC removal efficiency of (n)FeX was maximum and reached 476.2 mg g−1. The TC adsorption isotherms were fitted well by the Langmuir model. The adsorption kinetics were well described by both pseudo-second order equation and the intra-particle diffusion model. The TC removal efficiency was decreased as the pH of TC solution increased. The TC removal by (n)FeX was the chemical adsorption with cationic exchange reaction and electrostatic adsorption.