The world is experiencing resource depletion and water pollution caused by the use of fossil fuels.Reducing the shortage of freshwater resources and energy is an urgent problem to be solved.At present,several seawater desalination technologies have been developed.Compared with traditional seawater desalination technology,photothermal seawater desalination technology has more advantages,such as more safe and reliable,more environmentally friendly,and does not rely on conventional energy.The preparation of composite materials with excellent photothermal performance is the key to photothermal seawater desalination technology,and it is also the research focus of this paper.Two-dimensional MXene has a special layered structure and good photothermal conversion performance,which has potential applications in the field of photothermal seawater desalination,but it has high light reflectivity and poor stability.In order to solve the above problems,in this study,MXene/graphene composite aerogel and MXene/biomass carbon aerogel were prepared by hydrothermal self-assembly technology and impregnation method with graphene oxide and biomass materials.At the same time,we also studied the photothermal conversion performance of this material.The research contents and results are as follows:(1)Ti3C2TXwas prepared by HCl and LiF etching method using Ti3AlC2as raw material,and then Ti3C2TX/GA(graphene aerogel)was prepared by hydrothermal method and freeze-drying technology.The experimental results showed that Ti3C2TX/GA(6 m L)can rapidly heat up to 53.3°C in 60 s under 3 sun irradiation.The evaporation rate was 4.12Kg·m-2·h-1,and the evaporation efficiency reached 90.58%.Compared with pure GA aerogel,the photothermal performance of Ti3C2TX/GA(6m L)was significantly improved,and it can still maintain good photothermal conversion performance after 10 cycles.(2)Nb2CTXwas prepared by HF etching method using Nb2AlC MAX phase as raw material.Nb2CTX/GA composite aerogel was prepared by hydrothermal method and freeze-drying technology.The composite aerogel has a three-dimensional macroporous structure,excellent light absorption capacity and hydrophilicity.The effects of Nb2CTX/GA with different contents of Nb2CTXand different light intensities on the photothermal conversion performance were studied.It was found that the Nb2CTX/GA with 6 m L of Nb2CTXhad the best photothermal conversion performance.The evaporation rate can reach4.39 Kg·m-2·h-1under 3 sun irradiation,and the evaporation efficiency can reach 92.04%.It still maintained stable photothermal conversion performance after multiple cycles.(3)Carbon aerogels were obtained by microwave and tube furnace high temperature carbonization using rice grains as raw materials.Ti3C2TX/popcorn carbon aerogels were obtained by impregnation method.The optimum carbonization parameters were determined by temperature rise test of carbon popcorn with different carbonization time and temperature.The successful combination of popcorn carbon aerogel and Ti3C2TXwas proved by FESEM and TEM characterization.Through the experimental test of photothermal conversion performance,the more times of impregnation,the better the photothermal conversion performance.The evaporation rate of Ti3C2TX/popcorn carbon aerogels impregnated five times under 1 sun was 1.44 Kg·m-2·h-1,and the evaporation efficiency was 90.64%. |