Improving the performance of silica-based crossflow membranes by surface crystallization for treatment of oily wastewater

Today, hundreds of billions of barrels of oily wastewater is generated per day by a wide range of industrial applications. Depending on its hazardous nature, it is not possible to reuse or discharge the wastewater without any treatment. This study exhibits the fabrication of a ceramic filter, which is designed to obtain high recovery with high filtrate rate during the treatment of oily wastewaters. Tubular type ceramic filter was fabricated using an extrusion technique from local silica source, glass waste, and some organic additives. The length of the ceramic filter is 200 mm where the outer diameter and wall thickness are 12 and 3 mm, respectively. Dried samples were sintered at a temperature of 900, 950, and 1000 degrees C for 1 and 3 h of time, respectively. The effects of sintering conditions on the crystalline phase pore size and distribution, porosity, and permeability is discussed. The fabricated filters have high corrosion resistance for acidic (pH = 1.5) and basic (pH= 13) conditions (< 1% mass loss in both acid and basic media). The filtration performances of the ceramic filters are investigated by crossflow microfiltration via transmembrane pressure of 0.5-1 bar for synthetic oily wastewater. The relatively coarse pore size of the ceramic filter produced than the alternatives of the literature, achieves the oil separation efficiency rate up to 99.75%, which is attributed to the surface properties of the produced filter where the surfaces are negatively charged. According to the results, it could be said that the fabricated ceramic filter has high potential for microfiltration applications (oil level of the filtrate obtained is as less as 2 mg/L) and can be used as a support for ultrafiltration and nanofiltration technologies.