Catalytic ozonation of industrial wastewater containing chloro and nitro aromatics using modified diatomaceous porous filling

Abstract

The catalytic ozonation of industrial wastewater containing chloro and nitro aromatic compounds was carried out in a semi-continuous lab-scale reactor using Mn/Co modified porous diatomaceous ceramic fillings as catalysts. Results showed that the Mn/Co modified filling significantly enhanced the removal efficiencies of TOC and COD, as well as the ozone utilization efficiency over non-catalytic ozonation. A closer of scrutiny of catalytic ozonation system at neutral pH found that almost complete decolorization and removal of chloro and nitro pollutants were achieved after 80 min reaction time. A sharp decrease in pH and TOC and the formation of high concentrations of nitrate and chloride were observed at initial stage of ozonation. The effect of catalytic ozonation was evaluated on the subsequent biological treatment through biodegradability and acute toxicity tests. Catalytic ozonation significantly increased the biodegradability of industrial wastewater in company with toxicity reduction. Thus using coupled catalytic ozonation-sequencing batch reactor under neutral condition may be efficient and cost-effective in treating the wastewater.