Smart gating membrane based on polyzwitterion-modified SiO2 nanoparticles for water treatment and in-situ multi-modal detection

The smart gating membranes with stimuli-response permeation variations have attracted tremendous interest in the field of wastewater treatment. Specifically, successful integration of accurate porous architecture, precise water permeance regulation, long-term duration and in-situ detection of multiple environmental signals in a visualized way is highly desired yet still exclusive. Herein, a smart gating membrane with a combination of accurate porous adjustment and multi-signals detection is developed by assembling poly[2-(1-(4-vinylbenzyl) pyridin-1-ium-4-yl) ethane-1-sulfonate] (PVPES)-grafted SiO2 nanoparticles on cellulose membrane. The membrane exhibits uniform packing architecture with highly tunable water permeance from 0 to 15,330 L m−2 h−1 bar−1, mediated via polymeric shell thickness control and external salt-stimulation; besides, in-situ detection of heavy metal ions and pH values of the treated solution is simultaneously achieved via the pH-induced discoloration and heavy metal ion-dependent fluorescence of PVPES. What’s more, the membrane shows great mechanical stability against repeated bending, vibration or abrasion, as well as great anti-fouling capability, which together contributing to a long service life. We believe the membrane developed here will definitely promote the practical application of smart gating membranes.