Efficient resource utilization of coal gasification coarse slag (CGCS) is critical for ecological sustainability and industrial economics. A low-cost, high-performance catalyst loaded with cerium-manganese oxide (CeO2–MnO2/CGCS) was prepared via an impregnation-hydrothermal synthesis. The catalytic ozonation activity of CeO2–MnO2/CGCS was evaluated based on the removal rate of chemical oxygen demand (COD) for both simulated and actual coal chemical wastewater. For simulated wastewater, the COD removal rates of phenol-, naphthalene-, and benzofuran-containing wastewater were 81.2%, 58.9% and 56.6%, respectively, with the existence of CeO2–MnO2/CGCS, and the COD removal rate of mixed simulated wastewater containing the above compounds reached 66.3%. When CeO2–MnO2/CGCS was applied to actual coal chemical wastewater, the COD decreased from 200 to 36.5 mg/L with a removal rate of 81.7%. In comparison, the COD removal rate using a commercial catalyst was 72.9%, indicating the potential industrial application of CeO2–MnO2/CGCS. Furthermore, it was demonstrated that hydroxyl radicals (·OH) are the key reactive substances in the degradation of organics by adding a free radical scavenger (5,5-dimethyl-1-pyrroline-N-oxide) into the catalytic ozonation degradation of phenol-containing wastewater. Meanwhile, the mechanism of catalytic ozonation degradation of organics in coal chemical wastewater using CeO2–MnO2/CGCS as the catalyst is also proposed.
Xu et al. (Fri,) studied this question.