Highly stable two-dimensional AgCrSe2 membranes reinforced by polydopamine for contaminated water purification

Two-dimensional (2D) nanosheet membranes exhibit significant potential for molecular and ionic separation. Nonetheless, these membranes encounter swelling and oxidation issues when applied for the wastewater treatment in real-world scenarios. Herein, we report a novel approach to fabricate highly stable 2D membranes using AgCrSe nanosheets reinforced through the in-situ polydopamine (PDA) crosslinking. These AgCrSe-PDA membranes exhibit outstanding resistance to both acidic and alkaline conditions, as well as to oxidizing agents (e.g., 0.3 wt% HO), thereby demonstrating superior anti-swelling and anti-oxidation capabilities. The membranes achieve nearly 100% rejection rates for negatively charged dyes and heavy metal ions complexed with ethylene diamine tetraacetic acid (EDTA), with a permeance of approximately 5.0 L m h bar. Notably, the membrane maintains about 90% rejection efficiency for Cu-EDTA, with only a marginal decrease in flux, even after 140 h of cross-flow filtration. The robustness of the membrane is primarily attributed to the coordination interactions between PDA and the AgCrSe nanosheets. This study offers an innovative strategy for the development of stable 2D membranes, thereby extending their applicability in the treatment of industrially contaminated water. (Figure presented.).