Innovative Janus wood membranes: Harnessing wood anisotropy for superior liquid separation and transport
Kaiwen Chen, Xianfu Xiao, Cheng Hao, Fengze Sun, Haonan Zhang, Yujing Tan, Jianyi Zhu, Hui Peng, Tianyi Zhan, Jianxiong Lyu, Ning Yan
Abstract
This research harnessed the anisotropy of wood to develop two distinct asymmetric Janus wood membranes with varied wettability via plasticization and hydrophobic spraying. The cross-section Janus wood membrane effectively separated immiscible oil–water mixtures and collected fog, while the longitudinal one excelled at separates emulsions. This systematic development advanced wood membrane applications in advanced liquid separation and transport techniques. • Asymmetric wettability cross-sectional and longitudinal section Janus wood membranes based on wood anisotropy were prepared. • The Janus wood membranes had excellent mechanical properties, dimensional stability and mildew resistance. • The Janus wood membranes showed outstanding liquid transfer and separation performances. The asymmetric wettability of Janus membranes shows promising prospects in the field of liquid transport and separation, and researchers are seeking environmentally friendly and cost-effective feedstock for fabricating these membranes. In this study, we developed two types of high-performance, flexible, and durable asymmetric Janus membranes from wood: Janus cross-section wood membrane (JCW) and Janus longitudinal-section wood membrane (JLW). Wood, being an anisotropic material stemming from its grain orientation, possesses a hierarchical porous structure that can be tailored for various practical applications. The JCW, characterized by its vertical wood channel structure and larger pore size, demonstrated superior unidirectional water transport and fog collection capabilities. Its water–oil separation efficiency reached 99.9%, with a filtration flux exceeded 3000 L/m 2 ∙h. The JLW, featuring three-dimensional interconnected micro-nano channels and layered pathways, was particularly effective in separating oil–water emulsions. The separation efficiency of oil–water emulsions reached 99.91%, with filtration fluxes for water-in-oil and oil-in-water emulsions being as high as 500 and 700 L/m 2 ∙h, respectively. These results underscored the potential of asymmetric wettability Janus membranes in the fields of liquid transport and separation, while also paving the way for the utilization of sustainable and eco-friendly feedstocks.