Design And Preparation Of Solar Desalination Membrane Based On Acetylene Black

Water and energy are essential elements for life,economic development and social progress.At present,the shortage of fresh water resources and energy crisis have become urgent problems that human society must face.Existing technologies that address freshwater scarcity at the expense of exacerbating energy problems and improve access to water at the expense of the environment do not provide long-term solutions.Solar-powered interface desalination,which uses sunlight as an energy source,is widely seen as a very promising strategy for alleviating global water shortages.In practical application,the problems of salting out,poor stability,short service life,complex structure preparation technology and high cost are always wanted to be solved.In this paper,acetylene black was used as a photothermal material to prepare a double-layer photothermal conversion film by brush coating process.The evaporation performance of five kinds of photothermal conversion films with different support was studied under one sunlight intensity.The average evaporation rate of the photothermal conversion films with melamine foam as the support was the fastest,and the evaporation rate of the photothermal conversion films with nickel foam as the support was the most stable.In the photothermal conversion film prepared by brush coating method,the scanning images showed that acetylene black was attached to the skeleton and pore of nickel foam.Ultraviolet-visible near infrared spectroscopy shows that the absorption of solar energy by the photothermal conversion film is more than 93%in the wavelength range of 200 nm to2500 nm.The initial evaporation rate of seawater desalination is 0.89 kg m^-2 h^-1.After 24days of continuous evaporation test,the evaporation rate is stable at 0.9 kg m^-2 h^-1.In order to improve the evaporation rate of nickel foam supported photothermal conversion film,the effect of Fe₃O₄ and Ni Fe-MOF on the evaporation performance of composite photothermal material was studied.It was found that Fe₃O₄ could improve the light absorption capacity of photothermal conversion film,and the evaporation rate was increased to 1.07 kg m^-2 h^-1.The photothermal conversion film with melamine foam as the carrier has good salt resistance due to the double layer structure of hydrophobic layer.In order to improve the evaporation rate of photothermal conversion film,the influence of the thickness of melamine foam and the amount of acetylene black on the evaporation performance was studied.It was found that the evaporation rate was the fastest when the thickness of melamine foam was 20 mm and the amount of acetylene black was 0.75 g.At the same time,the effect of Fe₃O₄ on the evaporation performance of composite photothermal material was studied.The results show that when the amount of Fe₃O₄ is 0.05 g,the evaporation rate of photothermal conversion film is the fastest,which is 1.53 kg m^-2 h^-1.The photothermal conversion film supported by melamine foam was tested outdoors,and the evaporation rate was 1.28 kg m^-2 h^-1 under the average outdoor light intensity of 0.51kw m^-2.On this basis,the fresh water collection device was designed and manufactured by ourselves.The actual test showed that the ion concentration of Na⁺,K⁺,Ca²⁺and Mg²⁺in the fresh water obtained from evaporation was much lower than the drinking water standard issued by the World Health Organization.