Suitability of Different Titanium Dioxide Nanotube Morphologies for Photocatalytic Water Treatment

Abstract

Photocatalysis has long been touted as one of the most promising technologies for environmental remediation. The ability of photocatalysts to degrade a host of different pollutants, especially recalcitrant molecules, is certainly appealing. Titanium dioxide (TiO2) has been used extensively for this purpose. Anodic oxidation allows for the synthesis of a highly ordered nanotubular structure with a high degree of tunability. In this study, a series of TiO2 arrays were synthesised using different electrolytes and different potentials. Mixed anatase-rutile photocatalysts with excellent wettability were achieved with all the experimental iterations. Under UVA light, all the materials showed significant photoactivity towards different organic pollutants. The nanotubes synthesised in the ethylene glycol-based electrolyte exhibited the best performance, with near complete degradation of all the pollutants. The antibacterial activity of this same material was similarly high, with extremely low bacterial survival rates. Increasing the voltage resulted in wider and longer nanotubes, characteristics which increase the level of photocatalytic activity. The ease of synthesis coupled with the excellent activity makes this a viable material that can be used in flat-plate reactors and that is suitable for photocatalytic water treatment.

Photocatalytic Activity of Titanium Dioxide Nanotubes Following Long-Term Aging

“…The ability of these photocatalytic materials to breakdown bacteria commonly found in greywater was also investigated. Results from these investigations are reported in separate publications by the same authors [37,38].…”

Water Purification Using Choline-Amino Acid Ionic Liquids: Removal of Amoxicillin

“…Ozonation, advanced oxidation processes, such as the Fenton or photo-Fenton system, photocatalysis using TiO 2 , membrane processes (namely, ultrafiltration, nanofiltration, and osmosis) are some examples of novel treatment technologies to treat secondary effluents. Moreover, aqueous two-phase systems (ATPSs), also known as aqueous biphasic systems, constitute another promising extraction technology given their good potential for continuous operation, simple scaling-up, eco-friendliness, and mildness of extractive conditions. , …”

Hierarchical optofluidic microreactor for water purification using an array of TiO2 nanostructures

“…The former relates to light absorption and charge transport in photocatalysts, whereas the latter reflects the contact between the catalyst and the reactants, in addition to the removal of the products. To significantly enhance the photocatalytic efficiency, photocatalysts have been fabricated in various nanoscale geometric structures to provide large surface-to-volume ratios in the form of nanorods, nanotubes, and nanofibers using hydrothermal processes, sol-gel processes, or electrospinning [8][9][10][11][12][13][14][15] . However, the exchange with the catalyst is still limited as reactants and reaction products remain on the photocatalysts, which prevents further improvement of the water purification performance.…”