Multifunctional polyaniline modified calcium alginate aerogel membrane with antibacterial, oil-water separation, dye and heavy metal ions removal properties for complex water purification.

With the rapid development of urbanization, the discharge of industrial wastewater has led to increasingly critical water pollution issues. Additionally, heavy metals, organic dyes, microorganisms and oil pollution often coexist and have persistence and harmfulness. Developing materials that can treat these complex pollutants simultaneously has important practical significance. In this study, a calcium alginate-based aerogel membrane (PANI@CA membrane) was prepared by spraying, polymerization, Ca2+ cross-linking and freeze-drying using aniline and sodium alginate as raw materials. Oil-water emulsion can be separated by PANI@CA membrane only under gravity, and the separation efficiency was as high as 99 %. At the same time, the membrane can effectively intercept or adsorb organic dyes and heavy metal ions. The removal rates of methylene blue and Congo red were above 92 % and 63 % respectively even after ten times of cyclic filtration. The removal rate of Pb2+ was up to 95 %. In addition, PANI@CA membrane shows excellent photothermal conversion ability, and it can effectively kill Staphylococcus aureus under 808 nm laser irradiation. PANI@CA membrane has the advantages of low cost, simple preparation, good stability and high recycling ability, and has potential application prospects in wastewater treatment.