Solar-TiO2 immobilized photocatalytic reactors performance assessment in the degradation of methyl orange dye in aqueous solution

Abstract

Heterogeneous photocatalysis with titanium dioxide (TiO2) nanoparticles (NPs) has been demonstrated an emerging semiconductor material and widely been used in the treatment of wastewater due to is its high photocatalytic activity. In this study, TiO2 NPs with and without hydrolysis were synthesized by sol–gel and heat treatment methods. About 67 times higher surface area was obtained for TiO2 NPs synthesized with hydrolysis as compared to without hydrolysis. The X-ray diffraction showed an increased amount of anatase phase of TiO2 NPs with hydrolysis whereas the rutile phase of TiO2 NPs was obtained without hydrolysis. Immobilized-TiO2 NPs borosilicate glass (BG), cement coated borosilicate glass (CCBG), and steel wire mesh (SWM) reactors were constructed and the photocatalytic performance of TiO2 NPs was investigated to the degradation of methyl orange (MO) dye under solar irradiation. The photocatalytic removal of 10 mg/L MO dye was 97.8%, 88.6%, and 21.5%, respectively, at the same dose of immobilized-TiO2 on BG, CCBG, and SWM surfaces at pH 6.2 with 5 h of contact time. The kinetic study showed a pseudo-first-order reaction model fitted the best for MO dye removal. The increase of dye concentration decreases the performance of BG reactor, whereas, the addition of oxidant H2O2 increases the performance of BG reactor. The lowest TiO2 NPs loss from the study was observed for BG reactor (10.78%). This study indicates that the solar-TiO2 immobilized borosilicate glass reactor has high potential in the treatment of toxic compounds in textile wastewater.