Development of Red Clay Ultrafiltration Membranes for Oil-Water Separation

• Main Author: Saad A. Aljlil
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Crystals
• Subjects: ultrafiltration; red clay; calcium fluoride powder; wastewater; oil separation
• Online Access: https://www.mdpi.com/2073-4352/11/3/248

In this study, a red clay/nano-activated carbon membrane was investigated for the removal of oil from industrial wastewater. The sintering temperature was minimized using CaF₂ powder as a binder. The fabricated membrane was characterized by its mechanical properties, average pore size, and hydrophilicity. A contact angle of 67.3° and membrane spore size of 95.46 nm were obtained. The prepared membrane was tested by a cross-flow filtration process using an oil-water emulsion, and showed a promising permeate flux and oil rejection results. During the separation of oil from water, the flux increased from 191.38 to 284.99 L/m²on increasing the applied pressure from 3 to 6 bar. In addition, high water permeability was obtained for the fabricated membrane at low operating pressure. However, the membrane flux decreased from 490.28 to 367.32 L/m²·h due to oil deposition on the membrane surface; regardless, the maximum oil rejection was 99.96% at an oil concentration of 80 NTU and a pressure of 5 bar. The fabricated membrane was negatively charged, as were the oil droplets, thereby facilitating membrane purification through backwashing. The obtained ceramic membrane functioned well as a hydrophilic membrane and showed potential for use in oil wastewater treatment.