The Preparation And Photothermal Desalination Applications In Titania-Alumina Compound Oxide

Sunlight provides us with enough renewable energy resource being potentially converted into heat for steam generation,such as desalination.Nowadays,fresh water scarcity has become one of the most pressing issues facing mankind.Accordingly,a variety of seawater desalination technologies have been developed to cope with the water shortages,such as reverse osmosis?RO?and electric-to-thermal desalination.However,they are not capable of desalting high-salinity water with total dissolved salts concentration of above 3.8 wt.%.Photothermal desalination is envisaged to be a promising technology to alleviate the water scarcity because of its multiple advantages of energy saving,environment friendliness,and low water quality requirements.However,the exploration of low-cost but high-efficiency photothermal materials still remains a grand challenge.This paper have done the following works in order to find the suitable phtothermal materials for photothermal desalination.1.This paper use commercial TiO₂ and Al powder as raw materials to prepare a new Al-Ti-O nanostructure with tunable colors from gray to black by ball milling.Which couples the features of plasmonic effects in Al nanoparticles and high photoactivity in black TiO₂,enabling the optimized Al-Ti-O nanostructure shows a broad light absorption capability with almost covering 90.32%of solar spectrum.Inspiringly,the Al-Ti-O hybrid were assembled into a microporous membrane that can naturally float on the surface of water for photothermal desalination application,manifesting a high efficiency of 77.52%for desalination under simulated solar light irradiance,as well as an outstanding durability upon continuous running.In addition,a solar seawater desalination system was designed and manufactured,which can produce purified water with a rate of⁰.50 kg m^-22 h^-1,or⁴ L m^-22 day^-1,given that the effective sunshine time is 8 hours per day under current solar irradiation(⁸20 W m^-2).2.This paper also develop a template-free molten salt assisted method for the synthesis of a high efficient solar-thermal composite of the hollow black TiAlO_x by Galvanic replacement reaction of commercial TiO₂ with metallic Al with the assistance of molten Al Cl₃.Hollow black TiAlO_x features a high broadband light absorption with almost covering 90.2%of solar spectrum and holds a high efficiency of up to 71.1%in a high salinity solution containing 15.3 wt.%NaCl that is⁵ times more concentrated than seawater.A manual tracking solar desalting system with a photic area of 1.0 m²,and an upgraded automatic solar tracking desalination system were designed and produced independently.Meanwhile,the upgraded automatic solar tracking desalting system can run steadily for more than 5 days in high salinity environment?15.3 wt.%NaCl solution?under natural light,and the yield of pure water can still maintain as⁴ L m^-22 day^-1.3.In this paper,a self designed first generation automatic tracking solar desalination system is introduced,and the second generation system is upgraded based on the first generation system.At the same time,the construction of a manual desalination system with a photic area of 1 m² is completed.