A dual wastes-based aerogel with inverse beetles-like structure for enhanced oily wastewater treatment

Oily wastewater and solid wastes such as waterworks sludge (WS) and waste paper (WP) are usually treated separately. With the continuous promotion of the concept of waste-control-waste, the exploration of the collaborative treatment is worth considering. To address this gap, herein, a green and scalable strategy was developed to fabricate a hierarchical porous waterworks sludge and waste paper-based cellulose aerogel (WS0.6/WPC aerogel) with inverse beetles-like structure for enhanced and rapid oily wastewater treatment. Low-cost raw material and facile fabrication process allowed large-scale application of WS0.6/WPC aerogel. Significantly, underwater superoleophobic background composed of WS and WPC and hydrophobic bumps constructed of acrylic resin formed an inverse beetles-like structure. During emulsion separation, besides the high pore tortuosity of as-designed aerogel, the special hydrophobic bumps could capture and aggregate oil droplets, thus enhancing the interception ability of the aerogel, resulting in desirable separation efficiency for both immiscible oil/water mixtures and surfactant-stabilized oil-in-water emulsions with high fluxes. Therefore, this work provides insights for the exploration of wastes-based advanced membranes for efficient and rapid oily wastewater remediation, as well as recycling and utilization of solid wastes.