Chitosan-modified geopolymer sub-microparticles reinforced multifunctional membrane for enhanced removal of multiple contaminants in water

Nanoparticle-reinforced membranes have received widespread interest in water purification; however, their application is limited due to high cost, harsh conditions, and strong tendency of nanoparticles agglomeration and leaching. Herein, a multifunctional membrane was newly created by filling the pores of a glass fiber microfiltration membrane (GF) with chitosan-modified geopolymer sub-microparticles (CS-GMs) and crosslinking with polydopamine. Characterizations revealed that the introduction of CS-GMs was successful in regulating the porous structure of the membrane and suppressing membrane thickness growth and particle agglomeration. With an optimal dose of CS-GMs (0.45 g), the screening pore size of the membrane was regulated to 58 nm, thus showing a high rejection rate for microplastics (89.37%). In addition, the membrane was super-hydrophilic/underwater super-oleophobic and superior to the documented nanoparticle-reinforced membranes in decontaminating different oil-in-water emulsions (>99.5%) and co-existing pollutants (n-hexadecane: 99.62%, crystal violet: 94.51%, and lead ions: 99.62%) due to the effects of sieving and adsorption. Moreover, it possessed good reusability, rational environmental tolerance, long-term operational stability and point-of-use functions. Overall, this study paves the way for the feasible creation of low-cost, eco-friendly, and multifunctional sub-microparticle-reinforced membranes for the effective elimination of multiple contaminants in wastewater.