Reverse osmosis membrane with crown ethers decoration for enhanced radionuclides sieving

Abstract

Reverse osmosis (RO) membranes have been widely applied in the increasingly discharged radioactive wastewater treatment. However, conventional RO membranes suffer from the issues of the limited nuclides rejections and the relatively low water permeance. In this work, a new type of RO membrane with decoration of crown ethers (15C5 and 18C6) was prepared via an interfacial polymerization process to remove the radionuclide-contaminated components. Due to the special hollow structure of crown ethers (CEs) and the hydrogen bonding within the amidogen, the obtained MPD@15C5-TMC and MPD@18C6-TMC membranes exhibited smoother surfaces and thinner polyamide active layers than the pristine MPD-TMC membrane. The optimized MPD@15C5-TMC and MPD@18C6-TMC RO membranes presented excellent pure water permeances up to 2.16 and 2.91 L m−2 h−1 bar−1, and maintained high rejections towards Cs+, Sr2+ and Co2+, respectively. Furthermore, the membrane possessed a remarkable operational stability and an excellent anti-fouling property. These results confirmed the possibility of adopting crown ethers for RO membrane fabrication and verified their great potential for the practical application in removing radioactive elements from wastewater.