Mesoporous alumina membrane incorporated CuO/CeO2 catalyst for oily wastewater treatment

Abstract

Alumina hollow fibre exhibits an uncontrollable pore sieving which promotes intermediate pore blocking and fouling phenomenon during the operation, thus limits the membrane separation efficiencies. Therefore, to enhance filtration and selective properties of the membrane, mesoporous alumina was deposited on the outer surface of alumina hollow fibre using hydrothermal synthesis method in order to obtain a good crystalline membrane structure, highly uniform channel and narrow pore size distribution of membrane. The effect of different concentrations of mesoporous alumina suspension, synthesis times and calcination temperatures on the properties and separation performances of the prepared membranes were investigated. From the hydrothermal process, it was found that the optimum mesoporous alumina membrane was obtained at 1.2 M suspension concentration for 48 h reaction time, giving highest surface area of 236.495 m2/g and 9.8 µm thickness of mesoporous alumina on top layer alumina hollow fibre. It can be said that the highest reactants concentration would increase the rate of mesoporous alumina membranes formation. In addition, mesoporous alumina membranes were further analyzed using different pollutants (PEG and BSA) by varying calcination temperature within range of 550–900 ºC for its selectivity performance. The highest PEG and BSA filtration were observed by mesoporous alumina membrane calcined at 800 ºC, with the percentage of rejection at 85.7 % and 53 %, respectively. This result leads for selecting the membrane for oily emulsion filtration at 1000 ppm. Since the membranes pose low flux at 14.28 L/h.m2 with 52 % rejection on oily emulsion, modification on the membrane was carried out by incorporating the membranes with photocatalytic activity, at 3 wt. % of CuO/CeO2 photocatalyst using sol gel Pechini. The highest oil flux and rejection at 1422 L/h.m2 and 92 %, respectively, with the application of UV assisted online cleaning method. The results indicate that photocatalytic degradation of oil by CuO/CeO2 photocatalyst improved the membrane separation performance. This study provides an insight on the improved performances of fabricated mesoporous alumina membrane incorporated CuO/CeO2 photocatalyst on oily wastewater treatment which can be applied at industrial applications.