Optimize the preparation process of m-TiO2@CdS by response surface methodology to enhance the light intensity adaptability of photocatalytic degradation of tetracycline

Abstract

Catalyst performance is traditionally evaluated under high light intensity, where variations in e--h+ pair recombination rates at different light intensities may limit the applicability of the selected catalyst to diverse light sources. Response surface methodology (RSM) was employed to compare catalyst performance under two optimization processes, using tetracycline degradation rate and photon flux as response variables. The m-TiO2@CdS catalyst was characterized by XRD, SEM, TEM, XPS, and UV-Vis-DRS, and its preparation process was optimized using RSM, with precursor ratio, hydrothermal time, and temperature as variables. The proposed optimization model for tetracycline degradation rate and photon flux exhibited a strong correlation between predicted and experimental results. The tetracycline degradation rates for the two optimized preparation processes were nearly identical, at 61.87% and 61.18%, respectively. A comparison of tetracycline degradation kinetics under different light conditions (light saturation and non-saturation) for the two optimized m-TiO2@CdS samples demonstrated that the photon flux-based optimization model offered greater adaptability across a wider range of light intensities. Additionally, the repeatability of m-TiO2@CdS prepared under the optimal conditions was assessed, and a plausible mechanism for its photocatalytic degradation of tetracycline was proposed.