Photoelectrocatalytic oxidation of methyl orange on TiO2 nanotubular anode using a flowcell

Methyl orange from water was removed by photocatalytic anodic oxidation method using a titanium dioxide array surface. The coating was prepared by anodising a titanium plate using NH4F as electrolyte followed by heat treatment to render a photocatalytic surface under UV light. SEM imaging showed that the array coating consisted of closely spaced 1 m long, 0.1 m internal diameter tubes perpendicular to the titanium plate. The aqueous solution of methyl orange was circulated through a rectangular channel flow cell containing the coated anode and the effect of electrolyte flow rate and applied potential on the oxidation rate and efficiency were evaluated. At higher mean linear flow rates, the efficiency of the oxidation process improved, indicating a mass transport controlled process. At more positive applied potentials the TiO2 structure deteriorated resulted in lower oxidation efficiency.