LAUSR

Abstract Removing N-nitrosodimethylamine (NDMA), a regulated carcinogenic chemical, with a reverse osmosis (RO) membrane is a key challenge for enhancing the safety of reused potable water. This study aimed to achieve high rejection of NDMA and salts by plugging the nanopores in an RO membrane with linear-chain amines, amides, and epoxides. Plugging with amines or epoxides generally led to a reduction in water permeance and an increase in conductivity rejection. NDMA rejection increased linearly with the size of amines. The RO membrane plugged with dodecylamine exhibited an NDMA rejection of 80% when treating the effluent from a membrane bioreactor, and this performance was maintained for 8 d. In contrast, amide or epoxide plugs resulted in only minor improvements in NDMA rejection. We speculate that the amine plugs remain in the nanopores through electrostatic attractions, whereas amides and epoxides become readily detached from the nanopores because they are only bound through weaker hydrogen-bonding interactions. This study provides an understanding of the plugging mechanism that enhances NDMA rejection and demonstrated high NDMA rejection using treated wastewater.