Sustainable conversion of liquefied-chitin to anti-bacterial and photothermal polyurethane foams for efficient desalination of seawater

Interfacial solar-driven evaporation technology offers a sustainable and efficient solution to the global water crisis by harnessing solar energy to extract clean water from contaminated sources. Herein, we present a novel biomass-based polyurethane (PU) foam platform, engineered with carbon-based materials and a porous structure, for highly efficient solar-thermal desalination. To enhance both hydrophilicity and antibacterial properties, liquefied chitin, a sustainable biopolymer derived from marine waste, was innovatively utilized as a natural foaming agent. By integrating a hydrophilic polyacrylamide (PAM) layer and optimizing the dispersion of photothermal carbon materials, the designed foams exhibit rapid solar energy absorption and unidirectional water transport. This synergistic system achieves an exceptional water evaporation rate of 2.74 kg·m −2  h −1 and significantly reduces the water evaporation enthalpy by ~36.76 % (from 2248 J g −1 to 1548 J g −1 ). Remarkably, the desalinated water meets superior purity standards, with ion concentrations reduced to below 1 ppm, far exceeding the World Health Organization (WHO) guidelines for potable water. This innovative, eco-friendly strategy not only provides a scalable approach for seawater desalination but also holds great promise for advanced wastewater purification, offering a sustainable pathway to address global water scarcity.