A hierarchically cellulose porous monolith doped with CNTs/Al2O3 fibers, exhibiting super-hydrophilicity and underwater superoleophobicity for efficient solar-driven desalination

Abstract

The utilization of solar-driven interfacial desalination is widely regarded as a promising technological approach for mitigating the global water crisis. Existing solar interface evaporators often face limitations such as salt accumulation and oil waste liquid interference, impeding water supply channels and the efficient escape of interface water vapor, consequently diminishing the evaporation rate. This study proposes a novel approach by synthesizing a monolithic structure composed of carbon nanotubes (CNTs) and vertically arranged Al2O3 fibers which are embedded in cellulose skeleton, achieved through the thermally induced phase separation (TIPS) method. The resulting hierarchically porous monolith exhibits high steam generation rate, remarkable superhydrophilic properties and underwater superoleophobicity, rendering it highly effective in salt tolerance and resistance against oil pollution. In particular, highly oriented Al2O3 fibers form multiple thermal localization arrays and steam dissipation channels，complemented by interconnected hydrophilic skeleton that achieved strong synergy, enabling a stable and high evaporation rate of 1.98 kg m−2 h−1 and 2.06 kg m−2 h−1 in high salt concentration (10 wt%) seawater and oil-in-water (O/W) emulsion, respectively. This work contributes to the ongoing efforts in advancing next-generation solar vapor generators, aiming to enhance the sustainability and efficiency of freshwater production in response to the global water crisis.