Efficient degradation of tetracycline in aqueous solution by Ag/AgBr catalyst under solar irradiation

Abstract

To enhance the catalytic degradation efficiency of tetracycline (TC) in aqueous solution under solar irradiation, novel Ag/AgBr catalyst was prepared by surfactant assisted method, where an oil/water microemulsion was employed as synthesis medium. The Ag/AgBr catalyst was characterized by diverse techniques, such as SEM, XRD, XPS, BET, and DRS. Under sunlight irradiation, Ag/AgBr showed high photocatalytic capacity on TC degradation. To better understand the degradation mechanism, the important factors that affect the photocatalytic performance of TC were studied and optimized. The optimum conditions were 0.20 g L−1 of Ag/AgBr, 30 mg L−1 for TC, and pH of 11, respectively. The photodegradation kinetics of TC by Ag/AgBr catalyst complied with pseudo-first-order model. Based on our experimental facts, a possible photodegradation mechanism of Ag/AgBr has been proposed. Chemical oxygen demand (COD) could be decreased to approximate 99% under optimum experimental condition. Moreover, Ag/AgBr photocatalyst had good reuse performance for degrading TC. The obtained results show that the excellent photocatalytic capability of Ag/AgBr makes it feasible to utilize solar irradiation to degrade TC in solution.