pH-responsive BNNS/PAA nanofiltration membrane for tunable water permeance and efficient dye separation

Two-dimensional lamellar nanofiltration membranes have great application potential for water purification. Here, in order to achieve tunable water permeance and efficient dye separation, we reported a pH-responsive boron nitride nanosheets (BNNS)-based nanofiltration membrane by introducing polyacrylic acid (PAA). The strong hydrophilicity and electronegativity of PAA endow BNNS/PAA membrane with a fast water flux of 228 L & sdot;m(- 2)& sdot;h(- 1) and a high methylene blue (MLB) rejection of 98%, increased by 235% and 4% compared to the neat BNNS membrane, respectively. Owing to the size sieving effect, the BNNS/PAA membrane possesses the better selectivity for the different types of dyes and dye/salt mixture from the potential pollutants in the water. Meanwhile, it exhibits diverse and tunable nanofiltration performances at different pH, implying excellent pHresponsive ability of BNNS/PAA membrane. In addition, the BNNS/PAA membranes also display the exceptional separation and long-term stability at different environments. This work provides a novel and simple strategy for designing the BNNS-based nanofiltration membrane with the pH-responsive ability, the tunable water permeance and selectively.

Automated summary

A pH-responsive boron nitride nanosheets-based nanofiltration membrane with tunable water permeance and efficient dye separation was reported in this study. The membrane exhibited fast water flux, high rejection rate, and excellent selectivity for different types of dyes and dye/salt mixtures. It also displayed diverse and tunable nanofiltration performances at different pH and showed exceptional separation and long-term stability in various environments.