Activity, stability, and kinetic study of CuO/TiO2 Janus photocatalyst for rhodamine B degradation

Abstract

The CuO/TiO2 photocatalyst was synthesized using hydrothermal and sonochemical methods and subsequently applied to degrade rhodamine B in wastewater. The best synthesis conditions were established, determining Cu(NO3)2 solution concentration of 2.5 wt.% and calcination temperature of 500 °C. The CuO/TiO2 photocatalyst underwent characterization through various techniques, including inductively coupled plasma spectroscopy (ICP), photoluminescence, X-ray diffraction, ASAP, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy. TEM and SEM analyses revealed the presence of TiO2 nanowires and CuO nanoparticles. The Box–Behnken design, encompassing 27 experimental runs, assessed the impact of process variables such as initial dye concentration, pH, UV lamp power, and catalyst dose on the degradation process. The model's R2 value of 0.9893 indicated a high precision in fitting the predicted data to their actual values. Analysis of variance results highlighted UV irradiation power as the most significant variable within the design space. In addition, the CuO/TiO2 photocatalyst demonstrated efficacy under visible light irradiation. Light-expanded clay aggregate beads were chosen as the substrate for photocatalyst immobilization, which enhanced the reaction rate. The stability of CuO/TiO2 was evidenced by about 2% reduction in efficiency after four degradation cycles. HIGHLIGHTS Synthesis of the new nanostructure by the sonochemical method and the hydrothermal method.; Increased photocatalytic activity with no use of any oxidizing agent.; Synthesis of CuO nanoparticles/TiO2 nanowires with formulation of 56.5%CuO/43.4%TiO2.; Prioritization of photocatalysis variables based on analysis of variance.; Modeling and optimization of rhodamine B photodegradation.; Kinetics, stability test, and immobilized mode were investigated.;

Keywords

• cuo
• experimental design
• optimization
• rhodamine b wastewater
• tio2 nanowire