A study on the application of a composite MIL88A(Fe)/TiO2 in a hexagonal photoreactor for phenol removal: Response surface methodology and kinetic modeling

The application of a novel composite MIL88A(Fe)/TiO₂ for phenol removal in a new hexagonal photoreactor design was investigated. The unique hexagonal shape of the reactor increases the surface area available for irradiation, leading to more efficient removal of contaminants. The composite was characterized using X ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) images to determine its properties. Photocatalyst dosage, reaction time, phenol concentration, pH, and mL H₂O₂/L PW (phenol wastewater) were chosen as effective parameters on the process. To plan an experiment and maximize phenol removal, the response surface methodology (RSM) was applied. Ideal conditions for optimum efficiency (95.96%) include initial phenol concentration of 58 mg/L, pH of 7.51, reaction time of 68.61 min, mL H₂O₂/L PW of 0.18, and catalyst dosage of 0.4 g/L PW. Trapping experiments prove that ˙O₂ and ˙OH produced in Fenton and photocatalytic processes are the predominant active radicals in this process. The kinetics was fitted with the first-order, second-order, n-order, and Langmuir–Hinshelwood models using nonlinear least squares techniques. The n-order model with n = 0.54 was found to be the most suitable model (R² 0.998), with a model constant of k = 0.11 (mol^0.46/L^0.46.s).