Catalytic Destruction of 4‐Chlorophenol in Water

Abstract

Abstract4‐Chlorophenol (4‐CP) is a toxic, hazardous and persistent pollutant entering water mainly via the effluents of chemical industries. Catalytic wet oxidation has been the favored green chemistry path to convert this chlorinated organic to benign products. Wet oxidation was attempted in this work with MCM‐41 based catalysts impregnated with Fe(III), Co(II), and Ni(II). The catalysts were characterized with X‐ray diffraction, scanning electron microscopy, FTIR, cation exchange capacity, and atomic adsorption spectrophotometric measurements. 4‐CP oxidation was carried out in water, with and without hydrogen peroxide. The efficiency of the catalysts was tested with respect to reaction time, pH, mole ratio of the reactant and the oxidant, catalyst load, feed concentration, and temperature. The typical reaction conditions of temperature of 353 K, time 300 min, catalyst load 2 g/L, 4‐CP concentration 10–3 M could achieve 50.2, 55.0 and 58.2% oxidation in the presence of H2O2 and 48.5, 58.6 and 60.2% oxidation in the absence of H2O2 with Fe(III)‐, Co(II)‐, and Ni(II)‐MCM‐41, respectively. The reactions followed pseudo‐first‐order kinetics with respect to 4‐CP and the kinetic constant was between 1.4·10–3 and 3.5·10–3 Lg–1min–1. A mechanism for the oxidation of 4‐CP is suggested on the basis of product analysis.