Mechanism of organic fouling in the reverse osmosis process of coal chemical wastewater

Abstract

With the development and utilization of coal on a large scale, the treatment of coal chemical wastewater (CCW) had received extensive attention. This study utilized CCW from a coal liquefaction wastewater treatment plant to investigate the mechanism of organic fouling in the reverse osmosis (RO) process. CCW, which possessed high levels of organic matter, underwent RO process and resulted in significantly improved water quality, with a decrease in total organic carbon from 173.70 mg/L to 2.36 mg/L. However, the membrane surface was fouled by organic matter after continuous filtration for 14 h, causing a substantial reduction in the membrane flux, which decreased to 69.0 % normalized membrane flux. High molecular weight humic acid, the primary organic matter present in CCW, was found to be responsible for the organic fouling on the membrane surface, consistent with the main organic component of CCW. Moreover, organic foulants, including nitrogen heterocyclic compounds, alcohols, and lipids, were detected on the membrane surface. The study presented herein provides a comprehensive understanding and analysis of organic fouling in a RO system, offering crucial data support for the development of effective strategies to prevent and control RO membrane fouling in water treatment processes.