Preparation Of Graphene-polyaniline Light-to-heat Conversion Membrane And Its Application In Interface Evaporation

Interfacial solar desalination technology is an important environment-friendly and sustainable technology to solve the freshwater crisis.The existing system is often accomed by salt deposition during the evaporation process,which will weaken the light absorption capacity of the system,block the the water transport channel,and reduce the continuous evaporation efficiency.The rational design and performance improvement of interface seawater desalination materials have broad prospects.This paper with strong broadband absorption property,light thermal conversion and low thermal conductivity of polyaniline(PANI)and carbon based materials(Gr),through the interface solar desalination material and structure design,in the good light-to-heat conversion performance while reduce the salt deposition and ensure its sustainability,to promote the practical and industrialization of interface solar desalination technology provides new ideas.Firstly,the acid-doped polyaniline light-to-heat conversion membrane satisfies the interface evaporation conditions because of its good near-infrared absorption and its microporous structure and superhydrophilic characteristics.The effect of different acid doping on the light-to-heat conversion properties of polyaniline is investigated.Among them,the average absorption rate of PANI-PTSA membrane in the entire solar spectral range can reach 86.2%.Under one sunlight(1k W/m~2)irradiation,the water evaporation rate and solar conversion efficiency are 1.38 kg/(m~2h)and 80.7%,respectively,taking a leading position in the field of interfacial solar seawater desalination.Then,in order to further improve the optical absorption capacity,the relatively hydrophobic light-to-heat conversion material Graphene(Gr)is selected to produce the Graphene-polyaniline(m PANI-Gr)light-to-heat conversion membrane.The light-to-heat conversion and evaporation properties of m PANI-Gr membranes were studied and showed that the average solar spectral absorption of m PANI-Gr1 membranes with 7mg Gr can reach 80.9%,and the solar conversion rate reaches 1.55 kg/(m~2h)and 94%at 1sun,due to the relatively hydrophobic Gr on its surface,maintaining relatively stable and efficient evaporation performance after 13 hours.Finally,by blending Graphene with polyaniline membrane,further enhance the light absorption capacity,its surface roughness increases,reduce the light reflection,the average absorption rate in the whole solar spectral range can reach 90.9%,improve the overall performance,pore size and porosity increase ensure good water supply,reduce salt deposition,blending the water evaporation rate of 0.1Gr/m PANI membrane and solar conversion efficiency to 1.66 kg/(m~2h),solar conversion efficiency up to 100%.After0.1Gr/m PANI membrane circulation at 1sun,the simulated seawater evaporation rate could remain around 1.32kg/(m~2h),and both the water evaporation rate and solar energy conversion efficiency could not be significantly reduced within 13 h.Only a small amount of salt deposits on the membrane surface,proving that the 0.1Gr/m PANI membrane has good cycle stability and reuse,and then achieve continuous and efficient solar seawater desalination.