Study on the sonocatalytic removal of tetracycline by an type-II heterojunction CuS/FeWO4

Abstract

In this study, CuS/FeWO₄ composites were prepared by hydrothermal method, and the micro-morphological form, structural properties and light absorption capacity of the prepared samples were characterized by various technical means. The sonocatalytic activity of CuS/FeWO₄ composites was investigated through the removal of tetracycline. It was obtained that the CuS/FeWO₄ heterojunction formed by the combination of FeWO₄ spherical particles and CuS lamellar nanoparticles yields excellent sonocatalytic performance. Under the experimental conditions of 1.0 mg/mL of CuS/FeWO₄ sonocatalyst, 15 mg/L of TCL solution, 6.5 pH of TCL solution, 500 W of ultrasonic power, 50 kHz of ultrasonic frequency, and 120 min of ultrasonic time, the removal rate of TCL by CuS/FeWO₄ sonocatalyst reached 98.9 % ± 0.3 %. Compared to bare FeWO₄, the CuS/FeWO₄ heterojunction exhibited significantly higher sonocatalytic activity for the removal of TCL. The improved sonocatalytic activity was attributed to the built-in electric field effect resulting from the type-II heterojunction, which promoted the efficient separation of electron-hole pairs. After 4 cycles, the removal rate of TCL showed excellent stability and reusability. The results showed that type-II CuS/FeWO₄ heterojunction is a novel and efficient sonocatalyst, which is expected to be used in the field of environmental governance.