Easily Regenerated CuO/γ-Al2O3 for Persulfate-Based Catalytic Oxidation: Insights into the Deactivation and Regeneration Mechanism

• Published in: ACS applied materials & interfaces 2021-01, Vol.13 (2), p.2630-2641
• Main Authors: Wang, Jun, Li, Bin, Li, Yang, Fan, Xiaobin, Zhang, Fengbao, Zhang, Guoliang, Zhu, Yuanzhi, Peng, Wenchao
• Format: Article
• Language: English
• Subjects: Energy, Environmental, and Catalysis Applications
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c19013

In this work, γ-Al2O3-supported CuO (c-CuO/Al2O3) materials are successfully synthesized using a novel impregnation–precipitation–decomposition method. The obtained c-CuO/Al2O3 catalyst shows excellent catalytic activities for bisphenol A (BPA) degradation with sodium persulfate (PDS) as an oxidant. Radical quenching tests and electron paramagnetic resonance (EPR) studies indicate that PDS activation is a combined mechanism involving both free radical and nonfree radical pathways. In a continuous large-scale degradation process, about 1.78 L of 20 ppm BPA can be completely removed within 480 min. Although c-CuO/Al2O3 can be deactivated after several reaction cycles, the catalytic activity can be regenerated after simple aerobic calcination. X-ray photoelectron spectroscopy (XPS) and Raman analysis confirm that the deactivation of c-CuO/Al2O3 should be attributed to the conversion of Cu­(II) to Cu­(I). The aerobic calcination could oxidize Cu­(I) back to Cu­(II), thus recovering the catalytic activity. In addition, the density functional technology (DFT) and temperature-programmed oxidation (TPD) results reveal that γ-Al2O3 can not only serve as a carrier to anchor the CuO particles but also can adsorb and activate PDS by introducing more basic sites on the surface. c-CuO/Al2O3 has high activity and can be regenerated easily, thus having great potential applications for wastewater treatment.