Efficient simultaneous removal of tetracycline hydrochloride and Cr(VI) through photothermal-assisted photocatalytic-Fenton-like processes with CuOx/γ-Al2O3

Advanced oxidation processes (AOPs) based on photo-Fenton reaction has been widely used in refractory organic wastewater treatment. However, the mineralization rate and H2O2 utilization in AOPs is relatively low. Herein, a photothermal-assisted photocatalytic-Fenton-like process with CuOx/γ-Al2O3 catalyst was designed to solve the above issues. The utilization rate of H2O2 and mineralization rate of tetracycline hydrochloride (TC) in the 3%-CuOx/γ-Al2O3/H2O2/full spectrum light system were significantly increased to 72.0% and 74.3%, respectively, which were ascribed to the synergy of photothermal effect and photocatalytic-Fenton-like reaction. During the simultaneous removal of TC and Cr(VI), the reaction efficiency of 3%-CuOx/γ-Al2O3/H2O2/light system was much higher than that of 3%-CuOx/γ-Al2O3/H2O2 system. In addition, the 3%-CuOx/γ-Al2O3/H2O2/light system was not only active in wider pH range (3-9), but also effective in various organic pollutants and Cr(VI) coexisted solutions as well as different water conditions. More importantly, a possible photothermal-assisted photocatalytic-Fenton-like reaction mechanism for the simultaneous removal of TC and Cr(VI) in the CuOx/γ-Al2O3/H2O2/light system was proposed. This work may pave a new way for efficient simultaneous removal of refractory organic pollutants and heavy metals in wastewater.