Photocatalytic degradation of Remazol Red B and Rhodamine B dyes using TiO2 nanomaterial: estimation of the effective operating parameters

The presence of persistent organic pollutants (POPs) including dyes in the aquatic ecosystem is of major concern worldwide because of their hazardous effect, and human and environmental risks. The degradation of conventional wastewater plants costs a lot, due to increased environmental restrictions. Using photocatalysis to remove (POPs) is a promising, effective and sustainable process. A simple one-step sol–gel procedure for degradation of Remazol Red B (RRB) and Rhodamine B (RhB) has been used to synthesize titanium dioxide photocatalyst. Various techniques, such as X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, and parameters that influence the photodegradation process, including catalyst dose, pH, initial dye concentration, were used to study TiO2 photoactivity. The degradation of TiO2 via UV radiation for RRB and RhB after 75 min was 99.7% and 99.8% respectively. The photodegradation rates for two dyes using a Langmuir–Hinshelwood are shown pseudo-first-order. Besides, reactive species scavengers have been studied during degradation and the major species is OH• radicals. Photoluminescence experiments using terephthalic acid as a reference molecule determined OH• free radical formation during irradiation. Keywords: TiO2 ; Catalytic degradation; Sol–gel; Rhodamine B; Remazol Red B; Kinetics