Superhydrophilic quaternized calcium alginate based aerogel membrane for oil-water separation and removal of bacteria and dyes.

In recent years, frequent oil spills and increasing industrial wastewater discharge have caused serious water pollution problems. In addition, there are often microbial and dye pollutants in oil-containing wastewater. The development of materials that can simultaneously treat these three pollutants is very important for the safe treatment and recovery of wastewater. In this work, a modified calcium alginate-based aerogel membrane (CTW) was prepared through sol spraying, Ca2+ crosslinking and freeze drying by using tetrabutylammonium hydroxide (TBA) quaternary ammonium salt modified sodium alginate (SA) as raw material and waterborne polyurethane (WPU) as adhesive. The results show that CTW membrane has super hydrophilic and underwater super-oleophobic properties, and can realize the separation oil-water emulsions under gravity, with the separation efficiency of >99 %. CTW membrane can also remove bacteria and dye such as Congo red from water by filtration, with removal rates of 100 % and 99 % respectively. The filtration results of mixed wastewater show that CTW membrane can realize one-step separation of oil, bacteria and dye in wastewater, and can also be recycled, having potential application prospect. • A new kind of quaternized calcium alginate (CTW) membrane for one-step separation of complex wastewater was prepared. • The oil-in-water emulsion can achieve >99 % separation efficiency under the action of gravity. • CTW membranes have the ability to remove bacteria and dyes with removal rates of 100 % and 99 %, respectively. • CTW membrane can be recycled for oil water emulsion separation and dye removal. [ABSTRACT FROM AUTHOR]