Efficient photocatalytic degradation of metronidazole in wastewater under simulated sunlight using surfactant- and CuS-activated zeolite nanoparticles.

Hexadecyltrimethylammonium-bromide-activated zeolite nanoparticles coated with copper sulfide (ZEO/HDTMA-Br/CuS) was evaluated as a photocatalyst under sunlight for the degradation of metronidazole (MET). The surface and structural characteristics of ZEO/HDTMA-Br/CuS and other materials used in this study were analyzed using field emission-scanning electron microscopy, Fourier transform infrared and ultraviolet–visible diffuse reflectance spectroscopies, X-ray diffraction, Brunauer–Emmett–Teller surface area and Barrett–Joyner–Halenda pore size and volume analyses, and pH of zero charge test. ZEO/HDTMA-Br/CuS exhibited excellent surface and structural catalytic properties. For a comprehensive study of the degradation process, several parameters, such as the pH (3–11), MET concentration (10–30 mg/L), ZEO/HDTMA-Br/CuS dose (0.005–0.1 g/L), reaction time (5–200 min), and H 2 O 2 concentration (50–200 mg/L), were optimized. ZEO/HDTMA-Br/CuS achieved 100% degradation efficiency when 10 mg/L MET was used under the optimum conditions: pH = 7, ZEO/HDTMA-Br/CuS dose = 0.01 g/L, and reaction time = 180 min. The degradation efficiency increased when the concentration of H 2 O 2 was increased from 50 to 150 mg/L and decreased with further increase to 200 mg/L, indicating that the efficiency of MET degradation highly depends on the concentration of H 2 O 2 in an aqueous solution. The degradation kinetics analysis revealed that the degradation is of the pseudo first-order. Thus, ZEO/HDTMA-Br/CuS proved to be an exceptional catalyst for the photodegradation of MET in aqueous media. [Display omitted] • Photocatalytic degradation of metronidazole using sunlight is demonstrated. • Surfactant- and CuS-activated zeolite nanoparticles was used as a photocatalyst. • The used photocatalyst was an efficient and highly stable photocatalyst. • Under optimum conditions, 100% degradation of metronidazole was achieved. [ABSTRACT FROM AUTHOR]