Hierarchical porous cellulose membrane tethered with SiO2 nanoparticles as a sorbent’s platform for micropollutants removal

Micropollutants (MPs) present in water have shown increasing threat on the ecosystem. Membrane adsorption is playing an increasingly important role on the MPs removal but the synthesis of adsorptive membrane of high capacity remains challenging. This work proposed a strategy of grafting mesoporous nanoparticles onto macroporous membranes to prepare sorbents for MPs removal. The SiO2 nanoparticles with thiol groups (SiO2-SH) was introduced onto the RC membrane surface to prepare RC-SH membrane with a hierarchical porous structure. Specific adsorptive ligands, including itaconic acid (IA) or glycidol, was then immobilized to the RC-SH membrane surface via the thio-ene and thio-epoxy chemistry towards RC-IA and RC-PG membranes. Three kinds of adsorption membranes were obtained and their physical–chemical structure and morphologies were characterized by ATR-FTIR, XPS, SEM and BET. The grafted nanoparticles have been demonstrated to increase the surface area of the adsorptive membranes. The obtained adsorptive membranes, RC-SH, RC-IA, and RC-PG, show good adsorptive capacity for Hg(II) (179.0 mg/g) , Pb(II) (140.1 mg/g), and boron (2.55 mmol/g). The adsorption isotherm and kinetics fit well with Langmuir model and pseudo-second-order kinetic model, respectively. This work provides a universal method tethering porous nanoparticles onto the macroporous membrane surface for improved functionality capacity.