Photocatalytical degradation of Congo red (CR) dye via nano Titanium dioxide coated glass bead under UV light

Abstract

Titanium dioxide (TiO2) synthesized on nano-scale was coated firmly on soda lime glass beads used as catalyst support. The application of the Sol-gel method resulted in the formation of fine and nano-sized TiO2 particles uniformly dispersed and anchored on the soda lime glass beads by dry mixing method. A multi-column immobilized glass reactor was designed to evaluate the performance of the n-TiO2 coated glass bead by subjecting Congo-red (CR) dye to photo-catalytic degradation under U.V light. The effect of calcination temperature on TiO2 Anatase and Rutile phase transformation, preparation of Glass surface (etching) and effect of glass support on the catalyst performance, the CR dye concentration used and pH of solution, the dye degradation in dark condition and the impact of U.V light exposure, the duration of U.V light irradiation and its impact on the dye degradation, the catalyst (n-TiO2) loading used with the catalyst regeneration were some parameters studied to evaluate and optimize the performance of the n-TiO2 coated glass bead. It was observed that increased calcination temperature resulted in the phase transformation of anatase to rutile phase with complete rutile phase transformation at 800o C calcination temperature. The U.V spectroscopy studies signified that photo-catalytic degradation is optimized in acidic zone as lower pH favored the formation of more soluble CR ions. A reduction the n-TiO2 desecration was observed with profound catalyst regeneration cycle up to 5 times for the same catalyst used due to the employed glass bead support. The U.V light has optimized the CR dye degradation with 66% photo-catalytic dye degradation in just 10 minutes of U.V exposure. The TiO2 spherical structure and nano-sized particles formation was confirmed by SEM analysis and recorded in the range 130 to 270 nm. The elemental analysis was evaluated by EDX analysis and XRD analysis detected no characterization peaks other than TiO2 signifying the synthesis of pure TiO2 in the presented study. BET quantified the surface area analysis for the prepared samples with 26.18 and 5.32 m2/g surface area recorded for Titania samples prepared at 600o C and 800o C calcination temperature respectively. U.V spectrophotometer analysis appraised the CR dye degradation.