Photooxidation of wool dye and TCP in aqueous solution using an innovativeTiO2 mesh electrode

An innovative titanium dioxide (TiO2) mesh electrode was prepared by anodis ation, in which 0.5 M sulphuric acid was used as electrolyte and titanium ( Ti) metal mesh was anodised in a two stage anodic process. The innovated me sh electrode was examined using Raman spectroscopy to determine the formati on of TiO2 layer when different potentials of 120 V, 140 V, 160 V, and 180 V were applied in anodisation. Microporous surface of the electrode was als o examined using scanning electron microscopy. The photocatalytic (PC) oxid ation and photoelectrocatalytic (PEC) oxidation were studied using the new electrode for treating synthetic wastewater solutions of dye and trichlorop henol (TCP) respectively. The colour removal efficiency of 68% was achieved using the 160V-mesh electrode for treating wool dye solution after 80 minu tes reaction time. However, it was found that a significant substrate adsor ption on the surface of the mesh electrode could not be avoided when pH was below PHIEP of TiO2=6.3. In this condition, electrostatic adsorption occur red between the anionic substrate molecules and positively charged TiO2 sur face, The adsorbed substrate anion occupied most active sites of TiO2 on th e mesh electrode surface and significantly reduced the performance efficien cy of photo-oxidation, when the TiO2 mesh electrode was reused. The experim ent demonstrated that TCP adsorption on the mesh electrode could be signifi cantly eliminated, when pH of TCP solution was adjusted to above 7. When ra ising pH in TCP photodegradation eliminated substrate adsorption, it was co nfirmed that PC oxidation with application of a potential bias could enhanc e the photo-oxidation rate and a repeatable photo-oxidation rate could be m aintained when the same mesh electrode was reused in its following tests.