Heterogeneous degradation of tetracycline by magnetic Ag/AgCl/modified zeolite X–persulfate system under visible light

Abstract

Magnetic catalysts (Ag/AgCl/(x)FeX) were fabricated via a facile hydrothermal method followed by a precipitation–photo-reduction method. The Ag/AgCl/(x)FeX catalysts were applied to activate persulfate (PS) for tetracycline (TC) degradation. The degradation efficiencies of the Ag/AgCl/(x)FeX–PS system for TC removal were high due to the enhanced adsorptive capacity of (x)FeX, extended absorbance in the visible-light region and improved space separation of photo-induced charge carriers. The Ag/AgCl/(0.05)FeX catalyst exhibited better performance for TC removal compared with the other samples and complete degradation of TC could be achieved in 120 min by using 1 g L⁻¹ Ag/AgCl/(0.05)FeX and 5.0 mM PS at pH 3.5. The characterization of the catalysts and Electron Paramagnetic Resonance (EPR) studies indicated that TC was mainly degraded by surface-adsorbed radicals resulting from the reaction between PS and Fe(II) on the catalysts under visible light. The Ag/AgCl/(x)FeX–PS system provides new insights for contaminant removal from water.