Synthesis of CeO2-loaded composite catalysts of ZIF-67 for activation of persulfate degradation of Congo red dye

One of the most widely used and promoted synthetic dyes in the world is azo dyes, and the treatment of azo dyes wastewater is a hot issue. Currently, advanced oxidation technology is able to treat dye wastewater efficiently and the most critical means is to seek for suitable catalysts to activate the free radicals. In this study, ZIF-67@CeO2 composites were successfully synthesised by heating and refluxing and it degraded Congo red dye by activation of persulfate. The morphological structure of the composites was observed by using SEM, TEM, XPS, XRD, FT-IR and BET characterisation. In addition, the effects of different factors on the degradation of Congo red dye by the catalytic system were studied. And it was found that the best catalytic effect could be achieved at pH = 7, CeO2 loading of 0.3 g, and composite and potassium persulfate dosage of 10 mg and 0.3 g/L, respectively, and the degradation rate of the Congo red dye reached 98.8 %. Furthermore, the composite was able to maintain a better catalytic degradation effect after 4 cycles of regeneration experiments. Therefore, the ZIF-67@CeO2 composite as a new catalyst has a good application prospect in water treatment, which opens up a new avenue for the development of high-performance catalysts.