Prototype composite membranes of partially reduced graphene oxide/TiO2 for photocatalytic ultrafiltration water treatment under visible light

Abstract

a b s t r a c tA highly efficient hybrid photocatalytic/ultrafiltration process is demonstrated for water purification using visible light. The process relies on the development of partially reduced graphene oxide/TiO 2 composite membranes and their incorporation into an innovative water purification device that combines membrane filtration with semiconductor photocatalysis. Composites consisting of graphene oxide sheets decorated with TiO 2 nanoparticles were deposited and stabilized into the pores of ultrafiltration monochannel monoliths using the dip-coating technique. Cross-flow and dead-end filtration experiments were sequentially conducted in dark, under UV and visible light. The membrane surface was irradiated for the elimination of two synthetic azo-dyes, methyl orange and methylene blue, from water solutions. The synergetic effects of graphene oxide on pollutant adsorption and photocatalytic degradation capacity of TiO 2 were thoroughly studied, while the influence of the pore size of the monolithic substrate on the deposition morphologies was also elucidated. Moreover, the performance of the novel hybrid process was compared with that of standard nanofiltration with respect to pollutant removal efficiency and energy consumption, providing firm evidence for its economic feasibility and efficiency.

TiO2 nanocomposite based polymeric membranes: A review on performance improvement for various applications in chemical engineering processes

“…epoxide, carbonyl and carboxyl groups, it widely applied in developing organic-inorganic blend membranes especially in corporation with TiO 2 NPs[116][117][118][119][120][121][122]. Photodegradation of MB by using PSf/ TiO 2 -GO membranes assisted by UV light was investigated by Gao et al[116].…”

Photocatalytic degradation of hexavalent chromium emerging contaminant via advanced titanium dioxide nanostructures

“…As previously described [27], this irradiation density was achieved by four (4) near-UV radiation sources (lamps of 9 W, 315À380, Phillips UVA) with a peak at 365 nm and a length of 100 mm. Four (4) visible lamps of 9 W (Osram DULUX S 9W/21-840 G23 LUMILUXCool White, length 10 mm) were used to achieve a Vis light irradiation density of 7.2 mW cm À2 [28].…”

Graphene Derivatives in Photocatalysis

“…This active photocatalyst was also immobilized into the matrix of alginate porous hollow fibres (APHF), the resulting material hereafter labelled as GO-TiO 2 -4/APHF (Figure 8.9d), as reported elsewhere [91,115], presenting considerably high activity and stability in consecutive light-dark cycles of continuous reaction operation for the degradation of DP under near-UV/vis irradiation (Figure 8.9e), which is relevant for future technological applications. The same composite was also stabilized into the pores of ultrafiltration monochannel monoliths, which were tested in a hybrid photocatalytic/ultrafiltration process [116]. The synergetic effects of GO on pollutant adsorption and the photocatalytic degradation capacity of TiO 2 were thoroughly studied, and the influence of the pore size of the monolithic substrate on the deposition morphologies was also elucidated.…”