Biorenewable Polymer-Based Light-Absorbing Porous Hydrogel for Efficient Solar Steam Desalination
Junmo Jeon, So Hyun Lee, So Hyun Lee, Sang‐Ryong Lee, Sang‐Ryong Lee, Tae Hoon Seo, Young‐Kwan Kim
Abstract
An efficient interfacial heating system composed of a light-absorbing material and a hydrophilic porous support is developed through eco-friendly and energy-effective fabrication processes. Lignin nanoparticles (NPs) and cellulose nanofibers (CNFs) are harnessed as biorenewable light absorbers and hydrophilic supports, respectively. Lignin NPs are prepared using a solvent exchange process of the fractionated lignin with organic solvents to improve its π–π stacking and light-absorbing property for efficient photothermal conversion. Then, the lignin NPs are mixed with CNFs and lyophilized to obtain a light-absorbing porous hydrogel (LAPH), and the resulting LAPHs are covalently cross-linked and hybridized with Au NPs through a seed-mediated growth to further enhance their mechanical stability, hydrophilicity, and photothermal conversion properties. The resulting LAPHs exhibit an outstanding and prolonged performance as a solar steam generator such as high salt and pH tolerance, evaporation rate (3.17 kg m –2 h –1 ), and solar steam generation efficiency (83.4%) under 1 sun irradiation.