Bionic cellulose fiber-based columnar solar evaporator with interfacial regulation for superfast water purification

Solar interfacial evaporators (SIEs) with directional tubular structure have been well studied in seawater desalination. However, the lower water transporting ability always limits vaporing rate. Herein, inspired by the water transport mechanism of natural trees, we developed a unidirectionally orientated fiber-based columnar evaporator (CSCF) by simply treating cellulose acetate-based cigarette filter (CF) with sodium dodecyl sulfate (SDS) and carbon nanotubes (CNTs). Benefitting from the capillary and wicking effect of the original orientated fibers in CF, water could be effectively conducted to upper surface for solar evaporating process by loaded CNTs. Significantly, SDS could achieve homogeneous CNTs dispersing on CF, as well as regulate the liquid-solid and hydrophilic-hydrophobic interfacial environment to reduce water surface tension and evaporation enthalpy, which is helpful for further enhancing water transporting and rapid evaporating. Under 1 sun solar illumination, a superhigh and stable evaporation rate of 7.257 kg m −2  h −1 has been achieved. Additionally, even under dark condition, CSCF evaporator maintains high performance of 2.688 kg m −2  h −1 . It enables all-day evaporation while exhibiting excellent salt deposition resistance and long-term durability. This highly efficient and stable evaporator shows significant application prospects in seawater desalination, wastewater purification, and agricultural irrigation of cellulose derivative materials.