Improvement of coal gasification reverse osmosis concentrate treatment by Cu-Co-Mn/AC catalytic ozonation

Abstract

Approximately 20% of concentrate will be produced from coal gasification wastewater after reverse osmosis treatment. The organic matter contained in the concentrate affects its evaporation crystallisation; therefore, the refractory organics must be removed. In this study, Cu-Co-Mn/AC catalytic ozonation was used to treat reverse osmosis concentrate (ROC). With the addition of the Cu-Co-Mn/AC catalyst, the production of ·OH increased by 82 μmol/L, thereby enhancing the ozonation performance. The pH, ozone dosage, and catalyst dosage all affected the catalytic ozonation performance. By constructing a response surface model, it was found that the catalyst dosage had the most significant effect on the catalytic ozonation performance. The predicted optimal reaction conditions were pH = 9.02, ozone dosage = 1.08 g/L, and catalyst dosage = 1.33 g/L, under which the chemical oxygen demand (COD) removal reached a maximum of 81.49%. HIGHLIGHTS The Cu-Co-Mn/activated carbon catalyst enhanced the ozonation efficiency for treating reverse osmosis concentrate (ROC).; The removal of COD from ROC by catalytic ozonation could be about 80%.; A response surface model was established to determine the operating parameters of catalytic ozonation.;

Keywords

• catalytic ozonation
• response surface model
• reverse osmosis concentrate (roc)
• zero liquid discharge