Degradation of Refractory Organic Pollutants by Catalytic Ozonation -Effect of Water Background

摘要

A bench-scale, laboratory study is carried out to investigate the effect of water quality on MnOx/GAC heterogeneous catalytic ozonation. With the increase of pH the degradation efficiency of nitrobenzene increases in the case of ozonation, but decreases in the case of catalytic ozonation. The presence of magnesium ion, chloride, nitrate and bicarbonate has limited negative effect on the heterogeneous catalytic ozonation. It is suggested that the negative effect may be due to the interaction between inorganic ions and the surface of metal oxides. Low concentrations of humic substances (≤ 1 mg/L, as DOC) greatly enhances the degradation of nitrobenzene for both the catalytic ozonation and ozone oxidation alone; however, higher concentrations of humic substances have less degradation efficiency. It is also observed that the effect of humic acid on the adsorption of nitrobenzene is limited. In tap water, which contains some inorganic and organic substances, the degradation efficiency is lower than that in distilled water.