The Addition of Anthocyanin as a Sensitizer for TiO2 Nanotubes in a Combined Process of Electrocoagulation and Photocatalysis for Methylene Blue Removal

Abstract

Photocatalysis with TiO2 semiconductors is one of several potential methods for removing Methylene Blue (MB) that is environmentally friendly, relatively cheap, and effective. The capability of TiO2 photocatalysts for degrading MB can be improved by modifying the morphology of TiO2 into nanotubes and adding anthocyanin sensitizers. The objective of this study was to investigate the effect of anthocyanin sensitizer addition for TiO2 nanotubes on MB removal using a combined process of electrocoagulation and photocatalysis. TiO2 nanotubes were prepared through an anodization method with a glycerol electrolyte containing NH4F of 0.5% w/v and water of 25% v/v. The cathode and anode used in the electrocoagulation process were 316 stainless steel and aluminum, respectively. The characteristics of the resulting TiO2 nanotubes were analyzed using SEM-EDX, UV–Vis DRS, and XRD analyses. The results showed that the electrocoagulation at a pH of 10 and a voltage of 50 volts resulted in an MB removal efficiency of 57.88%. In the photocatalysis process, sensitizer addition can increase the MB removal efficiency from 19.71% to 29.06%. Furthermore, a combined process of electrocoagulation and photocatalysis without and with sensitizer addition resulted in MB removal efficiencies of 59.66% and 64.30%, respectively.