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

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 CO2-responsive cotton membrane (Ag/[email protected]) 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 CO2, the as-prepared Ag/[email protected] could reversibly switch from superhydrophobic (uncharged) state to superhydrophilic (charged) state. Moreover, the Ag/AgCl endowed the Ag/[email protected] with visible light photocatalytic activity. Based on these ingenious features, the as-prepared Ag/[email protected] could bidirectional separation of various oil/water mixtures with high separation efficiencies (≥97.50%), accompanying with satisfactory fluxes, due to controllable wettability upon CO2 stimulation. Moreover, the as-prepared Ag/[email protected] exhibited stable oil/water separation property, even under various adverse environmental conditions. Meanwhile, the Ag/[email protected] 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/[email protected] under both static and dynamic states in the presence of CO2. The maximum static adsorption capacity of the Ag/[email protected] 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/[email protected] toward RhB (cationic dye) was up to 94.30% within 6 h. Most importantly, the as-prepared Ag/[email protected] exhibited photo-induced self-cleaning performance due to the existence of Ag/AgCl, which endowed it with excellent recyclability. Additionally, the as-prepared Ag/[email protected] displayed outstanding antibacterial activity. In summary, the Ag/[email protected] could be viewed as a satisfactory material for oil/water separation and dyes removal and exhibits great potential in wastewater remediation.