▎ 摘　　要

NOVELTY - A photothermal hydrogel comprises a photothermal material dispersed in an amphoteric polyelectrolyte hydrogel. The photothermal hydrogel is obtained by copolymerizing an amphoteric polyelectrolyte monomer, a cross-linking agent, an initiator and a photothermal material mixture. USE - The photothermal hydrogel is used for solar photothermal heating of water surface (claimed) and for treating high-concentration saline water, seawater, industrial wastewater and other sewage. ADVANTAGE - The Photothermal hydrogel is biologically safe. The pollution caused on the surface of the material, using traditional photothermal steam conversion material, is avoided by using the photothermal hydrogel. The hydrogel also prolongs the service life of the material used in photothermal steam conversion application. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for the preparation of polyelectrolyte thermal hydrogel which involves: (1) dispersing an amphoteric polyelectrolyte monomer, cross-linking agent, initiator and a photo-thermal material in water to obtain a pre-polymerization mixture; (2) copolymerizing the obtained prepolymerization mixture by heating or lighting; (3) soaking in water to remove unreacted raw materials, to obtain the amphoteric polyelectrolyte photo-thermal hydrogel.