Ceramic Membranes In Hybrid Photocatalysis/Ultrafiltration Processes

Abstract

The current work demonstrates the efficiency of a hybrid Photocatalysis/Ultrafiltration process to eliminate or reduce the contents of synthetic dyes in wastewater. The process involves highly active photocatalytic ceramic ultrafiltration membranes prepared with the deposition of various photocatalysts on both sides of UF mono-channel monoliths. Anatase TiO2 was deposited with chemical vapor deposition (CVD) and sol-gel (dip-coating) techniques. Novel materials such as modified TiO2 with an organic shell layer and reduced graphene oxide-TiO2 (rGO/TiO2) were also synthesised and stabilised on the surface and pore structure of the monoliths with the target to develop visible light responding membranes. The photocatalytic filtration experiments took place in a prototype water purification device in continuous flow conditions, using methylene blue (MB) and methyl orange (MO) as azo-dye model pollutants, under near-UV/Vis and visible light irradiation. The influence of several parameters, such as feed pressure, feed concentration and flow rate, on the pollutant degradation efficiency and membranes permeability was investigated and analysed. Furthermore, the novel hybrid process is compared with the standard Nanofiltration technique in regard to the pollutant removal efficiency and energy consumption.