Preparation and characterization of γ-alumina ceramic ultrafiltration membranes for pretreatment of oily wastewater

摘要

The main goal of the present study is to prepare -alumina (-Al2O3) ultrafiltration (UF) membranes for separation of oil from a real oily wastewater. A -Al2O3 multilayer UF membrane on an -alumina (-Al2O3) substrate was successfully fabricated via the sol-gel processing method. The prepared layer from the -Al2O3 colloidal sol as the membrane top layer had an average pore size of 20.3nm and thickness of 4m. The resulting -Al2O3 multilayer UF membrane did exhibit homogeneity with no cracks or pinholes. Permeate flux (PF) through the membranes was calculated. Response surface methodology (RSM) based on Box-Behnken design was used to design the experiments and analyze three operating parameters including transmembrane pressure (TMP), feed temperature (T), and cross-flow velocity (CFV). The optimum PF of 112.7kg/m(2)h was identified by RSM at feed temperature of 35 degrees C, TMP of 5bar and CFV of 0.735m/s. The results showed that these membranes are efficient for treatment of petroleum refinery wastewater, so that total suspended solids, chemical oxygen demand, biological oxygen demand, total organic carbon, oil and grease content, turbidity, and pH are reduced by 86, 73, 63, 67, 84, 79, and 7%, respectively. The prepared -Al2O3 UF membranes exhibited great potential to be employed as an advanced method for pretreatment of oily wastewater due to its ability for physical separation of contaminants and commercial aspects.