Ag-TiO2 nanosheet embedded photocatalytic membrane for solar water treatment

Abstract

Solar photocatalytic degradation of contaminants in waste water using nanocatalysts is potentially sustainable water treatment. The major challenges in using nano size photocatalysts is catalyst recovery and its toxic effect. In the present work, the problem of catalyst recovery is mitigated by immobilising the photocatalyst on the surface of a membrane by pressurized ultrafiltration method. The membrane thus synthesised is capable of simultaneously degrading and filtering the pollutants. The photocatalyst employed in this work is silver doped TiO2 nanosheets, their thin structure and larger size favoured stable film formation on the membrane surface. The nanosheets were synthesised via hydrothermal route and their photocatalytic efficiency was future enhanced by doping with silver. The nanosheets were characterised using scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy. Photocatalytic degradation studies were conducted using Congo red dye as the model pollutant. The effect of catalyst loading on permeation properties and dye removal were studied under ultra violet irradiation. M-200 membrane with Ag-TNS loading of 136.98 gm-2 was found optimum for superior flux and dye removal. M-200 membrane also showed good performance under solar radiation. 2017 Elsevier Ltd.