Multifunctional Janus bamboo-derived aerogel with asymmetric surface wettability for efficient oil-water separation...

Oily wastewater often contains coexisting heavy metal ions, posing a challenge for traditional separation materials that cannot remove both pollutants simultaneously. A Janus bilayer aerogel (BCNF/MXene-BCNF/PDMS) with asymmetric wettability is reported, featuring a hydrophobic upper layer with a water contact angle (WCA) of 133° and a hydrophilic lower layer with a WCA of 0°. The Janus structure introduces asymmetric stress distribution, significantly enhancing the mechanical performance of aerogel (compressive strength up to 127 kPa). Owing to its asymmetric wettability and interconnected network structure, the design prevents oil fouling of adsorption sites by spatially separating oil absorption from metal-ion adsorption, thereby enabling simultaneous treatment of both pollutants in a single process. Benefiting from these structural features, the aerogel achieved over 95% oil-water separation efficiency, a flux of 19,099 L·h^-1·m^-2 under vacuum assistance, and a Cr(VI) adsorption capacity of 206.2 mg·g^-1. Compared with single-function or uniformly wetting materials, this design enables synergistic removal of oil and heavy metal ions from complex wastewater. With these properties, the prepared aerogel has significant potential for treating complex, heavy-metal-contaminated oily wastewater.