Multifunctional Ag/AgCl decorated CO2-responsive cotton membranes with photo-induced self-cleaning property for efficient bidirectional oil/water separation and dyes removal

Abstract

Development of multifunctional materials for efficient treatment of complex effluents containing water-insoluble oils and water-soluble dyes is highly desired. In this work, a multifunctional Ag/AgCl decorated CO 2 - responsive cotton membrane (Ag/AgCl@PCM) was successfully fabricated for simultaneous or successive removal of oils and dyes (both cationic and anionic dyes). Through achieving protonation and deprotonation in response to the CO 2 , the as-prepared Ag/AgCl@PCM could reversibly switch from superhydrophobic (uncharged) state to superhydrophilic (charged) state. Moreover, the Ag/AgCl endowed the Ag/AgCl@PCM with visible light photocatalytic activity. Based on these ingenious features, the as-prepared Ag/AgCl@PCM could bidirectional separation of various oil/water mixtures with high separation efficiencies (≥97.50%), accompanying with satisfactory fluxes, due to controllable wettability upon CO 2 stimulation. Moreover, the as-prepared Ag/AgCl@PCM exhibited stable oil/water separation property, even under various adverse environmental conditions. Meanwhile, the Ag/AgCl@PCM could eliminate the dyes in wastewater through adsorption for anionic dyes and photocatalysis for cationic dyes. The results presented that MB (anionic dye) could be efficiently removed by the Ag/AgCl@PCM under both static and dynamic states in the presence of CO 2 . The maximum static adsorption capacity of the Ag/AgCl@PCM toward MB reached 2168.47 mg g −1 with a fast adsorption rate (12 min of adsorption equilibrium time). For the removal of cationic dyes, the photo-degradation efficiency of the Ag/AgCl@PCM toward RhB (cationic dye) was up to 94.30% within 6 h. Most importantly, the as-prepared Ag/AgCl@PCM exhibited photo-induced self-cleaning performance due to the existence of Ag/AgCl, which endowed it with excellent recyclability. Additionally, the as-prepared Ag/AgCl@PCM displayed outstanding antibacterial activity. In summary, the Ag/AgCl@PCM could be viewed as a satisfactory material for oil/water separation and dyes removal and exhibits great potential in wastewater remediation. • Filtration, adsorption and photocatalysis are combined for complex water treatment. • Ag/AgCl@PCM displays CO 2 controllable and efficient oil/water separation behavior. • Ag/AgCl@PCM removes anionic dye by adsorption and cationic dye by photocatalysis. • Ag/AgCl@PCM exhibits photo-induced self-cleaning feature and good recyclability.