Janus structured cellulose-based aerogel with vertical channels and conical roof for efficient solar-driven water evaporation and pollutant degradation

Abstract

Solar-driven water evaporation technology has become a research hotspot due to its effective utilization of solar energy to purify water resources. However, current water evaporation materials still encounter challenges such as limited evaporation rates, insufficient water/heat management capabilities, and inadequate removal of complex pollutants. This study demonstrates a novel Janus solar evaporator (HZC-CNF) based on the TEMPO-oxidized cellulose nanofibril (TOCNF) aerogel for a synergy of photothermal water evaporation and pollutant degradation. The unique structures of vertically aligned channels and conical roof not only enable the light adsorption and multiple scattering, but also enhance the evaporation area and water transport paths. Meanwhile, the silanization modification of the photothermal layer effectively reduces its heat loss to further enhance the thermal management capability. Moreover, the cellulose-based aerogel with abundant hydrogen-bonding network can lower the water evaporation enthalpy, and the well-dispersed ZIF-67 catalysts among the evaporator matrix deliver the efficient degradation towards various organic pollutants. Results show that HZC-CNF exhibits an excellent photothermal conversion capability (surface temperature 90 °C), a good water evaporation rate of 1.97 kg m⁻² h⁻¹, and sound removal efficiencies for various pollutants including ciprofloxacin (>90 %), providing an innovative pathway for sustainable water resource management.