Preparation and Characterization of Single Layer Ultra Filtration Alumina Membrane Directly over Porous Clay-Alumina Tubular and Capillary Support for Textile Effluent Treatment

Abstract

Clay-alumina porous tubular supports of 8/6 mm for outside diameter/inside diameter (OD/ID) were prepared by extrusion and sintering at 1450°C for 110 min to obtain an average pore size of 1 µm and porosity of 40%. Slip casting slurry was prepared by peptization of boehmite (AlO(OH)) powder with 1.5 N nitric acid and mixing it with γ-Al2O3 powder of 40 nm particle size along with PVA and PEG in determined weight percentage. Clay alumina porous support tubes of 3.1/1.9 and 8/6 mm (OD/ID) were coated with the slip casting slurry and sintered at 550°C for 60 min to obtain γ-alumina membrane directly over the supports in a single step. The membrane layer prepared over both the support tubes were without any intermediate layer. The membranes presented a pore diameter distribution centered at 7.0 nm on 3.1/1.9 mm (OD/ID) and 5.5 nm on 8/6 mm (OD/ID) supports, which was in ultrafiltration (UF) range. The prepared UF membranes were studied for treatment of bio-treated synthetic and real textile effluent in the side stream mode. About 98% decolorization of synthetic dye solution and 95.6% colour removal of real textile effluent were obtained by the combined effect of UF membrane and bioreactor.