The catalytic properties of manganese oxides supported on a novel type of copper-containing silica gel for tricyclazole degradation with ozone

Abstract

An Mn oxide supported on a novel type of copper-containing silica gel (Mn-CuSG) has been fabricated by an impregnation-calcination method and tested in the catalytic ozonation of tricyclazole (TC). An inductively coupled plasma optical emission spectrometer and scanning electron microscopy equipped with an energy dispersive spectrometer were used to reveal that the Mn element was successfully loaded and uniformly distributed on the CuSG. The catalytic activity was systematically assessed by monitoring the TC and total organic carbon (TOC) removal efficiencies at different operational parameters including catalyst dosage, initial solution pH, and ozone concentration. The O3 /Mn-CuSG system performed higher activity than ozone alone and O3 /Mn-γ-Al2 O3 system, improving the TC removal efficiencies by 28% and 9%, respectively and TOC removal efficiencies by 24% and 6%, respectively. The Mn-CuSG catalytic activity was only a slight loss after five consecutive cyclic treatments, showing good stability. The addition of t-butanol as hydroxyl radicals scavengers proved that the catalytic ozonation mechanism was the enhancement of molecular ozone attacks and • OH generation by the Mn-CuSG. TC degradation pathway in the O3 /Mn-CuSG system was that the attacks of the 1,2,4-triazole ring resulting in the formation of N-oxides and hydroxylated intermediates. The above results render the Mn-CuSG an industrially promising candidate for catalytic ozonation of TC containing wastewater.