Synergistic adsorption-photocatalytic activity using Z-scheme based magnetic ZnFe2O4/CuWO4 heterojunction for tetracycline removal

Developing efficient and economical photocatalysts was considered as an efficient and economical strategy for pollution remediation. Herein, magnetically separable ZnFe 2 O 4 /CuWO 4 composites (ZW) had been developed via combining ZnFe 2 O 4 with CuWO 4 . The composite with a mass ratio of 40% CuWO 4 (ZW-40) performed best, and the tetracycline hydrochloride (TC) removal by adsorption-photocatalysis of ZW-40 reached 86.5%. The photocatalytic degradation rated constant of it was 9.44 × 10 −3 min −1 , which was approximately 5.04 and 3.28 times compared to the ZnFe 2 O 4 and CuWO 4 samples, respectively. Pseudo-second-order kinetic models could describe well the TC adsorption process, in which chemisorption was the major driving factor, with the maximum adsorption at 23.56 mg g −1 . The improved photo-catalytic capability owed to the formation of Z-scheme heterojunctions with ZnFe 2 O 4 and CuWO 4 , which improved the intensity of visible light absorption and enhanced the separation electron-hole pairs as well as the redox capability of the composite. ZW-40 was high stability as its removal ability of TC in different water conditions slightly dropped about 15% after 5 cycles. ZW-40 could effectively remove TC in different water matrix, its removal ability for 40 mg/L was as follows: super-pure water> municipal wastewater> swine farm wastewater. Hence, the complexation of ZnFe 2 O 4 with CuWO 4 provides a valuable strategy to improve the photocatalytic potential for ZnFe 2 O 4 -based catalysts as well as providing a promising pathway for water clarification. • A novel ZnFe 2 O 4 /CuWO 4 (ZW) Z-scheme heterojunction was successfully constructed. • Heterojunction between ZnFe 2 O 4 and CuWO 4 promotes the electron-hole pair separation. • Synergistic adsorption-photocatalysis could more effectively remove tetracycline. • The ZW composite was relatively effective to remove TC from the wastewater.