Simulation of photocatalytic degradation of methylene blue using titanium dioxide (TiO2) P25 as a photocatalyst

Abstract

The annual production of textile dyes exceeds 70,000 per year, with nearly 200,000 tons of synthetic dyes being released into the environment due to inefficient dyeing methods used by textile industries. The contamination of water bodies by textile wastewater has been found to have adverse effects on human health, underscoring the need to remove these pollutants. In this study, methylene blue was used as a representative pollutant to assess the effectiveness of photocatalytic degradation using TiO2 P25 as a photocatalyst. The PHOTOREAC software, a user-friendly open-access computational tool developed in MATLAB specifically for modeling and simulating large-scale solar photocatalytic reactors in environmental applications, was employed to simulate both a kinetic model and a photon absorption scattering. The secondary data were classified based on several operating conditions, including the incident light source, light intensity, and photoreactor configurations, to investigate the impact of each condition. The results obtained from the PHOTOREAC simulation and secondary data analysis indicated that a solar simulator utilizing a xenon lamp as the incident light source is preferable for photocatalytic degradation due to its constant irradiation compared to natural solar light. Increasing the light intensity of the incident light source from 300 W/m2 to 1000 W/m2 also enhances the photocatalytic degradation performance. The optimum loading of the photocatalyst exhibits variation, ranging from 8 to 15 g/L. The efficiency of photocatalytic degradation is influenced by various properties of the photocatalyst, such as the crystal structure, surface area, crystallite size, and band gap energy. Furthermore, the Langmuir Hinshelwood and the Ballari models are the most suitable kinetic model expression for guiding photocatalytic degradation of methylene blue.