Pollutant degradation over dye sensitized nitrogen doped titania substances in different configurations of visible light helical flow photoreactor

Abstract

Abstract Different nitrogen doped titania (N-TiO2) substances were synthesized, sensitized with hematoporphyrin (HP) and their thin films were fabricated on supporting structures. Two kinds of supporting, wire gauze structured packing and quartz Raschig ring random packing were utilized in a visible light, helical flow photoreactor. The HP/N-TiO2 nanohybrid powders, suspended in the solutions, were also prepared to compare their photocatalytic activity. Different techniques of SEM, TG–DTA, XRD, FT-IR, UV–Vis spectroscopy and elemental analysis were used to characterize the products. Methyl orange (MO) substrate was used as a model dye pollutant in aqueous solutions with measuring the level of degradation and TOC. The influencing parameters like the amount of sensitizing HP, nanohybrid dosage, film thickness and repetitive operating capability were investigated and optimum mild conditions were obtained. The process kinetic was well fitted by pseudo first order kinetic model and the electrical energy was drastically less than those reported for other similar processes. Among the employed configurations, the random packing showed the highest efficiency and the lowest energy consumption. Meanwhile, the HP/N-TiO2 with 3 mM initial concentration of HP represents a potential alternative for the treatment. Comparison with similar processes represents the superior performance of the process.