Green Synthesis of an Environmentally Benign Wood Fiber-Based Superamphiphilic Aerogel for Continuous Separation of Emulsions with High Flux

Oil contamination from petroleum extraction, machining, and chemical manufacturing is a major environmental problem. Superwetting materials treat oily wastewater by selectively repelling oil or water based on surface wettability. Although highly efficient, this process causes interfacial fouling due to accumulated oil or water, which reduces long-term stability and hinders continuous separation. Herein, we report green synthesis of an environmentally benign wood fiber-based superamphiphilic aerogel (MWCNTs/WFA@Ca2+) by coating calcium alginate hydrogels onto three-dimensional scaffolds of natural wood fibers. The as-prepared MWCNTs/WFA@Ca2+ featured a high porosity of 81.69% and superamphiphilicity, which facilitated the simultaneous high-flux permeation of both water and oil phases and selectively captured the water phase within its extensive porous architecture that served as a volumetric storage domain via its underoil superhydrophilicity. Consequently, MWCNTs/WFA@Ca2+ exhibited outstanding separation performances toward diverse W/O emulsions with surfactants and achieved a high flux of up to 7006 L m–2 h–1, a separation efficiency of up to 99.50%, and stable continuous separation of 1035 mL of W/O emulsions. Even after the fifth cycle, the efficiency and flux were maintained at 99.64% and 6718 L m–2 h–1, respectively. Our investigations provided a feasible green strategy for preparation of superamphiphilic aerogels and extended for the resource utilization of wood fibers in achieving ultrastable continuous separation of emulsions with high flux.