An Expanded Perlite-Based Aerogel with Oil-Repellent Properties for Efficient Solar Evaporation in Oil-bearing Wastewater

Graphical The photothermal conversion material (CAEP-PFO) was prepared by using expanded perlite as raw material and sodium alginate as crosslinking agent, through directional freezing, surface carbonization and oil-phobic modification. CAEP-PFO has a porosity of 92 %, a light absorption of more than 88 %, and a low thermal conductivity of 0.06834 W m −1 K −1 , providing excellent thermal insulation performance. Solar steam generation (SSG) has become a cutting-edge technology to solve fresh water shortage. Herein, a neotype photothermal conversion material (CAEP-PFO) was designed and prepared by using expanded perlite as raw material and sodium alginate as crosslinking agent, through directional freezing, surface carbonization and oil-phobic modification. Through characterization analysis, the results showed that the prepared CAEP-PFO has a porosity of 92 %, a light absorption of more than 88 %, and a low thermal conductivity of 0.06834 W m −1 K −1 . In addition, CAEP-PFO exhibits excellent salt resistance and oil repellency, and possess an evaporation efficiency of 78.6 % in 10 % brine and 80.2 % in oil-bearing wastewater under the irradiation of 1 kW m −2 , respectively. After 8 cycles of test, the evaporation efficiency in pure water is relatively stable, and the average evaporation efficiency can reach 84.28 %. The research may lay a foundation for the future preparation of photothermal materials and the practical application in seawater and oil-bearing wastewater.