Removal and transport behavior of trace organic compounds and degradation byproducts in forward osmosis process: Effects of operation conditions and membrane properties

Abstract

The issue of trace organic compounds (TOrCs) is constantly increasing owing to the requirement of improvements to the quality of life and the development of analytical technologies. To remove the TOrCs in waste water, advanced oxidation processes (AOPs) were introduced owing to their effective degradation of the TOrCs. However, these methods can transform the TOrCs into toxic degradation byproducts (BPs). Forward osmosis (FO) studies were recently conducted for removing the TOrCs in the water treatment process because it is a cost-effective process using the osmotic pressure difference between the feed solution (FS) and the draw solution (DS). However, the studies comparing the original TOrCs and their degradation BPs following removal or adsorption were not conducted in FO membranes. To identify the possibility of an FO process as a post-treatment or alternative process to the AOPs, the removal and adsorption of the original TOrCs and degradation BPs were evaluated under various conditions such as pH (5, 7), draw solutes (NaCl, MgSO4), and membrane properties (cellulose triacetate, polyamide). The original TOrCs (85.5–93.4%) were observed to have a higher rejection rate than the degradation BPs (53.6–68.9%), except for carbamazepine (73.8%) and acridine (85.5%) on the cellulose triacetate (CTA)-based FO membrane.