Fully Biomass-Based Hybrid Hydrogel for Efficient Solar Desalination with Salt Self-Cleaning Property

Abstract

Solar-driven interfacial steam generation provides an opportunity for solar harvesting and freshwater yield as a promising and eco-friendly technology. Here, we demonstrate a sustainable, nontoxic, and highly efficient fully biomass-based GG/CI hydrogel evaporator consisting of gellan gum (GG) hydrogel as the matrix and cuttlefish ink (CI) as the photothermal material. Induced by the ice-template method and freeze-drying method, vertically aligned microchannels are generated along the ice crystal growth direction. Efficient photothermal conversion is enabled by the natural black cuttlefish ink powder and enhanced by the light trapping effect within vertical microchannels. The hydrophilic property of the gellan gum hydrogel and water capillary force in those microchannels boost water pumping to the top interfacial evaporation region. Effective rapid salt self-cleaning behavior is achieved due to the rapid ion diffusion within vertical microchannels. An evaporation rate of 3.1 kg m–2 h–1 under one sun irradiance is demonstrated by this fully biomass-based GG/CI hydrogel evaporator. This work offers a promising alternative for eco-friendly and sustainable freshwater generation with abundant natural biomasses.

Diatom-Inspired TiO2-PANi-Decorated Bilayer Photothermal Foam for Solar-Driven Clean Water Generation

“…Since the capillary water was activated by hydrophilic groups on TiO 2 -PANi@MF, the evaporation enthalpy of capillary water decreased when the evaporation takes place at liquid–solid interfaces. The effective evaporation enthalpy of capillary water within TiO 2 -PANi@MF was 1554.5 J/g. , Therefore, based on formula , the solar steam conversion efficiency of bulk saltwater, MF, PANi@MF, and TiO 2 -PANi@MF are 28.8, 51.3, 95.8, and 88.9%, respectively. Significantly, the solar steam conversion efficiencies of PANi@MF and TiO 2 -PANi@MF are significantly higher than that of MF.…”

“…The effective evaporation enthalpy of capillary water within TiO 2 -PANi@MF was 1554.5 J/g. 37,38 Therefore, based on formula 3, the solar steam conversion efficiency of bulk saltwater, MF, PANi@MF, and TiO 2 -PANi@MF are 28.8, 51.3, 95.8, and 88.9%, respectively. Significantly, the solar steam conversion efficiencies of PANi@MF and TiO 2 -PANi@ MF are significantly higher than that of MF.…”

Recent advances in structural regulation and optimization of high-performance solar-driven interfacial evaporation systems

“…A hydrogel evaporator with vertical microchannels composed of cuttlesh ink and gellan gum shows 97% absorption of sunlight and an evaporation rate of 3.1 kg m À2 h À1 under one sun. 122 Furthermore, several kinds of hybridizing materials can improve photothermal performance owing to the synergistic effects. Plasmonic metal nanoparticles have absorption peaks at specic wavelengths.…”

“…A hydrogel evaporator with vertical microchannels composed of cuttlefish ink and gellan gum shows 97% absorption of sunlight and an evaporation rate of 3.1 kg m −2 h −1 under one sun. 122…”

Aerogels in passive solar thermal desalination: a review

“…Therefore, to achieve a longlasting high production rate in practical applications, the designed evaporator should be fouling-resistant with saltrejecting properties. [27][28][29] Recrystallization of the remaining salt ions aer water evaporation can block water transport channels causing a serious challenge of "salt accumulation". Most studies on salt-rejecting water evaporators have focused on NaCl accumulation, but the existence of divalent salts (i.e., Ca 2+ , SO 4 2À , and CO 3…”