CNT/polyimide fiber-based 3D photothermal aerogel for high-efficiency and long-lasting seawater desalination

Abstract

Solar steam regeneration is considered an efficient way to desalinate seawater and alleviate the global shortage of freshwater resources. However, the poor mechanical properties, low evaporation rates, and short service life of the currently reported materials can not meet the requirement of actual applications. Here, a composite aerogel with high porosity up to 97.8% was developed by physically cross-linking the electrospinning PI fibers as the backbone and carbon nanotubes as the photothermal component. This composite aerogel composite reached the maximum temperature within 20 s and showed a stable evaporation rate of 2.08 kg m−2 h−1 under 1 sun irradiation (1 kW m−2). In simulated seawater distillation experiments, the material achieved 99% removal efficiency for various concentrations of NaCl solution. The aerogel consisting of polyimide backbone exhibited excellent UV resistance, showing an insignificant change in morphology and evaporation rate under continuous irradiation for 1 h at 40 mW cm−2 under 365 nm UV light. This study provides a reliable solution for developing high-performance solar evaporators with high porosity and endurance.