Dual polyethyleneimine-incorporated nanofibrous membranes for ultra-efficient adsorptive removal of haloacetic acids from water

Haloacetic acids (HAAs), a class of disinfection by-products (DBPs) commonly found in potable water, pose significant risks to human health. It is challenging for conventional membrane filtration technologies to efficiently remove HAAs from water due to their small molecular sizes, as size-sieving effects often dominate the separation process. In this work, a nanofibrous membrane was developed for the rapid and effective adsorptive removal of HAAs from water. A two-step intensified strategy was employed to fabricate the adsorptive membrane: polyethyleneimine (PEI) was incorporated during electrospinning to provide abundant amine-based adsorption sites, followed by a co-deposition process involving PEI and dopamine (DA) to enhance interfacial contact between water and the membrane. The resulting membrane exhibited a high specific surface area, significant porosity, and improved hydrophilicity, all of which contributed to its strong adsorption capacity for HAAs. As a result, the membrane demonstrated an exceptional water flux of up to 260 L·h −1 ·m −2 under a 2.5 cm water column, with dihaloacetic acids (DCAA) treating capacity of 36 mg·m −2 and a removal efficiency exceeding 93%. Furthermore, an adsorptive membrane module with an effective area of 0.27 m 2 was fabricated, achieving an ultrahigh treating capacity of 297 mg·m −2 for five HAAs, a removal efficiency exceeding 99%, and a water flux of 370 L·h −1 ·m −2 ·bar −1 —two orders of magnitude higher than that of conventional membranes. This work presents a simple yet highly effective strategy for the enhanced removal of DBPs, highlighting its strong potential for practical applications in drinking water purification.