Study of Phenol Red Photocatalytic Decomposition on KBrO3-Supported TiO2 Nanoparticles for Wastewater Treatment

In this study, the enhanced photodegradation of a high-concentration phenol red (PR) using very fine TiO2 nanocrystals by adding a KBrO3 electron acceptor was reported for the first time. The structural study on TiO2 nanocrystals using HRTEM, XRD, Raman, and EDX was performed and it confirmed the anatase phase of TiO2 nanocrystals. UV-Vis absorbance of 20 mg.L-1 PR was measured and the photodegradation was extracted. The KBrO3 concentration effects exhibited an important enhancement in the degradation of PR dye. The efficiency of PR was increased during 110 min from 75% of pure TiO2 to 92% and 98% of TiO2 with 1 mg and 5 mg KBrO3, respectively. For different samples, a first-order kinetic of dye degradation is confirmed. The instantaneous amount of degraded dye increased from 150 to 180 and 197 mg/g TiO2 with 1 mg and 5 mg KBrO3, respectively. The mechanism of the photodegradation reaction confirms the effect of OH- radicals on increasing the photocatalytic activities. The addition of electron acceptors KBrO3 improved the photocatalysis rate, where it prevented e-h recombination through conduction band electron capture, which increases the concentration of hydroxyl radicals. The proposed mechanism and results were supported by photocurrent measurements and a Raman spectra analysis of the final photodegraded products. The photocurrent of TiO2 was observed at 1.2 mu A, which was significantly improved up to 13.2, and 21.3 mu A with the addition of 1 mg and 5 mg of KBrO3. The Raman spectra of the final products confirmed that SO42- and carbons are byproducts of PR degradation.

Automated summary

In this study, the enhanced photodegradation of high-concentration phenol red (PR) using fine TiO2 nanocrystals and KBrO3 as an electron acceptor is reported for the first time. The structural analysis confirmed the anatase phase of the TiO2 nanocrystals. The addition of KBrO3 resulted in an important enhancement in the degradation of PR dye. The proposed mechanism suggests that the OH- radicals play a crucial role in increasing the photocatalytic activities, and the addition of KBrO3 prevents e-h recombination and increases the concentration of hydroxyl radicals.