The synergistic mechanism of photocatalytic-assisted dye degradation has been demonstrated using a hybrid ZnO-MoS2-deposited photocatalytic membrane (PCM). Few layers of MoS2 sheets were produced using the facile and efficient surfactant-assisted liquid-phase exfoliation method. In this process, hydrophilic moieties of an anionic surfactant were adsorbed on the surface of MoS2, which aided exfoliation and promoted a stable dispersion due to the higher negative zeta potential of the exfoliated MoS2 sheets. Further, the decoration of ZnO on the exfoliated MoS2 sheets offered a bandgap energy reduction to about 2.77 eV, thus achieving an 87.12% degradation of methylene blue (MB) dye within 15 min of near UV-A irradiation (365 nm), as compared with pristine ZnO achieving only 56.89%. The photocatalysis-enhanced membrane filtration studies on the ZnO-MoS2 PCM showed a complete removal of MB dye (~99.95%). The UV-assisted dye degradation on the ZnO-MoS2 PCM offered a reduced membrane resistance, with the permeate flux gradually improving with the increase in the UV-irradiation time. The regeneration of the active ZnO-MoS2 layer also proved to be quite efficient with no compromise in the dye removal efficiency.
Keywords: dye degradation; hybrid ZnO-MoS2 layer; membrane filtration; photocatalytic membrane; surface modification; surfactant-assisted exfoliation.