Preparation of Ag(3)PO(4)/CoWO(4) S-scheme heterojunction and study on sonocatalytic degradation of tetracycline

In this study, 0.6Ag(3)PO(4)/CoWO(4) composites were synthesized by hydrothermal method. The prepared materials were systematically characterized by techniques of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), N(2) adsorption/desorption, and UV–vis diffuse reflectance spectrum (DRS). Furthermore, the sonocatalytic degradation performance of 0.6Ag(3)PO(4)/CoWO(4) composites towards tetracycline (TC) was investigated under ultrasonic radiation. The results showed that, combined with potassium persulfate (K(2)S(2)O(8)), the 0.6Ag(3)PO(4)/CoWO(4) composites achieved a high sonocatalytic degradation efficiency of 97.89 % within 10 min, which was much better than bare Ag(3)PO(4) or CoWO(4). By measuring the electrochemical properties, it was proposed that the degradation mechanism of 0.6Ag(3)PO(4)/CoWO(4) is the formation of S-scheme heterojunction, which increases the separation efficiency of electron-hole pairs (e(-)-h(+)) and generates more electrons and holes, thereby enhancing the degradation activity. The scavenger experiments confirmed that hole (h(+)) was the primary active substance in degrading TC, and free radicals (•OH) and superoxide anion radical (•O(2)(–)) were auxiliary active substances. The results indicated that 0.6Ag(3)PO(4)/CoWO(4) nanocomposites could be used as an efficient and reliable sonocatalyst for wastewater treatment.