Cellulose based pH-responsive smart membrane for selective removal of oil and water

Abstract

Background: Removal of oil and organic compounds from industrial wastewater is of great importance to environmental pollution control. However, efficient, simple and cost-effective separation of such pollutants from water is still challenging. Methods: A cellulose-based pH-responsive smart membrane with excellent reversible wettability was developed. Cellulose membrane was coated with polydopamine (PDA) to introduce the reactive sites for further modification. Dimethylaminopropylamine (DMAPA) and octadecylamine (ODA) were selected as pH-responsive and hydrophobic materials, respectively. Significant findings: The modified cellulose membrane switches surface wettability between hydrophobic under neutral condition and hydrophilic in acidic environment (pH 2). Therefore, this cellulose membrane has great applicability to selectively remove oil or water according to the pH of water. The membrane exhibited high separation efficiency of 99 % in both cases. The membrane also absorbed the oil in water and desorbed it while immersing in acid (pH 2) presenting the “self-cleaning” ability. Such a smart membrane has significant potential in oil-water separation