A temperature-responsive, repairable and renewable self-floating hydrogel steam generator

The design and synthesis of materials dedicated to solar evaporation have attracted substantial attention. Hydrogels, known for their elevated evaporation rates, are perceived as potential candidates in the subsequent evolution of solar evaporation technology. This research introduces an efficient, harmless, and sustainable design of a porous hydrogel interface evaporator, possessing self-repair and regenerative capabilities. For a hydrogel matrix composed of carrageenan and konjac gum, an element of activated carbon serving as a light absorber is integrated. Notably, the evaporator's capability for regeneration and repair is facilitated by the unique thermally reversible three-dimensional architecture of carrageenan. The konjac gum provides the interpenetrating network with carrageenan, which significantly enhances the hydrogel's mechanical durability. Additionally, its hydroxyl-rich components precisely modulate the state and content of the water molecules, contributing to reduce the enthalpy of water evaporation. Lastly, the inclusion of activated carbon effectively mitigates the retention of low-boiling-point contaminants and endows the hydrogel with a light absorption of 97 %. These outstanding benefits result in an evaporation rate as high as 2.6 kg m−2 h−1 for the formulated hydrogel. Given the ready availability of raw materials, this biomass evaporator introduces new prospects for eco-friendly solar evaporators.