Optimization of novel polyester membranes coated with TiO2 - a-Fe2O3 for photodegradation of oxytetracycline

Abstract

Oxy-tetracycline (OTC) is a bio-recalcitrant pollutant that commonly enters the environment via excretion or runoff and is difficult to eliminate through convention wastewater treatment processes. To tackle this issue, advanced techniques like photocatalytic membranes are necessary. This study involved synthesis of TiO2-α-Fe2O3 photocatalysts and incorporating them into polyester membranes. The photocatalytic membranes were characterization using digital microscopy for optical properties, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) for morphology and composition, X-ray Diffraction (XRD) for crystal structure, and Fourier Transform Infrared (FTIR) for functional groups. Response Surface Methodology (RSM) was applied to optimize key parameters; water flow rate, initial OTC concentration, and pH to maximize the degradation efficiency. Graphical response surfaces and contour plots identified optimal conditions: a water flow rate of 5.5 L/hr, pH of 5, and a treatment time of 2 h for degrading 10 mg/L of OTC. The membrane color changed from white to red confirming the presence of TiO2-α-Fe2O3. The SEM, EDX, and XRD results were indicative of effective nanoparticle incorporation without altering the membrane crystalline structure. The ANOVA indicated a high R² value of 0.9917, suggesting a good model fit. The photocatalytic membranes achieved 93 % degradation of OTC under sunlight demonstrating high effectiveness against bio-recalcitrant antibiotics pollutants such as OTC.