The recovery of organic and inorganic constituents for reuse as valuable by-products and chemicals during wastewater treatment is facilitated by a thin-film composite nano-porous membrane engineered to improve the separation and energy efficiencies of the electrodialysis process.

The membrane sports a crustacean-inspired coating composed of the polymer polyethyleneimine and polydopamine (PDA). The latter is a compound secreted by mussels to adhere to solid surfaces in their aqueous environment. The sticky nature of the PDA imparts high selectivity to the membrane, allowing water to pass through but blocking other compounds and offering a low-energy route to saline water filtration and chemicals fractionation.

When tested for the removal of different antibiotic compounds, the coated membrane demonstrated high recovery efficiency in extracting these chemicals from saltwater solutions. A desalination efficiency of more than 99% and antibiotic recovery of more than 99.1% were documented. The membrane with bio-inspired coating is expected to perform highly effective electrodialytic separation of various organic/salt mixed solutions more effectively than standard existing processes deployed for industrial wastewater treatment.

The research published in Nature Water was conducted by scientists from the Chinese Academy of Sciences, Fujian Agriculture and Forestry University (China), Fuzhou University (China), Hanyang University (South Korea), Singapore Institute of Technology, Hunan University (China), Nanyang Technological University (Singapore), Korea Institute of Energy Technology (South Korea), Deakin University (Australia), KU Leuven (Belgium) and the University of Bath (U.K.).