Boric Acid’s Dual Role in Controlling Interfacial Polymerization for High-Performance Reverse Osmosis Membranes with Enhanced Water Permeability and Contaminant Sieving

Microelectronics manufacturing generates substantial wastewater, containing toxic contaminants. Although the reverse osmosis (RO) membrane is a promising treatment technology, its suboptimal water permeance and limited rejection of low-molecular weight (MW) organic contaminants restrict its practical application. Herein, we present a simple approach for developing RO membranes fabricated via interfacial polymerization with boric acid as an additive, which enhances the water permeance and superior removal efficiency for low-MW contaminants in microelectronic wastewater. The boric acid-modified RO membranes exhibited a remarkable increase in water permeance up to ∼4.2 L/(m2·h·bar), a 3-fold enhancement compared to the pristine membrane thanks to the formation of smoother and thinner polyamide (PA) layers. Meanwhile, owing to the denser PA layers, the modified membranes reached a 2–18% higher removal efficiency for common low-MW contaminants in microelectronic wastewater compared to the commercial membranes. The penetration of organic substances through the modified membranes in real wastewater was decreased by 50% with respect to that of the commercial membranes. The hydrogen bonding interaction between the amine monomer and boric acid, along with the buffering effect of boric acid, collectively promoted the formation of denser and thinner PA layers. This study offers valuable insights into the development of RO membranes for the recovery of microelectronic wastewater or analogous effluents containing low-MW contaminants from the perspective of interfacial polymerization regulation.