| The development of solar-driven interface evaporation technology is of great significance to solve the problem of water shortage.Aiming at the problem s of insufficient research on the salt crystals accumulating in the field of interface evaporation and the stability of evaporation efficiency.This thesis designs and develops a solar-driven interface evaporator and efficiency monitoring system with low cost,high efficiency and strong salt-resistance.The focus of the research are:(1)Following the design perspective of high efficiency and low cost,design low-tortuosity and salt-resistant biomass-based photothermal materials.(2)Innovatively designing and perparing a long-term salt-resistant solar evaporator based on"migration crystallization"by referring to the coffee-ring effect and the regular growth mechanism of crystal nuclei.(3)Using the relationship between the solution ion concentration difference and the electric potential,a set of evaporation efficiency monitoring device is designed to monitor the performance changes of the photothermal materials in the long-term solar-driven interface evaporation system.The main content and conclusions are as follows:(1)Two new low-tortuosity photothermal materials(P-CSA and P-CSMA)were designed by using cornstalk-based ultralight porous foam as substrate and loading polypyrrole.P-CSA and P-CSMA exhibited excellent photothermal performance,with solar evaporation efficiencies of 89.74%and 96.8%under 1 kW m-2 irradiation,respectively.In particular,the large pore structure with low tortuosity inside P-CSMA resulted in good salt-resistance during the photothermal process.In 20 wt%Na Cl solution,the solar evaporation efficiency of P-CSMA could still reach 94.7%under 1k W m-2irradiation.In the continuous evaporation experiment under natural light conditions,P-CSMA demonstrated great long-term salt-tresistance performance of no salt crystals on sample‘s surface for 30 days,which proved that P-CSMA could be used as an efficient salt-resistant photothermal material in the solar interface evaporation process.(2)The carbonized filamentous algae was modified by ultraviolet light to prepare a super-hydrophilic photothermal material(SH-CGA).Due to the restriction of pore structure,the salt-resistance of SH-CGA was poor,which was a common problem for micro-nanoporous and low-porosity photothermal materials in the desalination process.For this reason,this thesis designed a set of evaporator that can migrate s alt crystals.This evaporator device significantly improve d the salt-resistance of SH-CGA,so that after 15 days of continuous evaporation under natural sunlight,there was still no obvious salt deposition on the surface.Moreover,the device realized the simultaneous collection of distilled water and salt,which provided a novel and universal method for optimizing the salt-resistance of photothermal materials and the extraction of salt.(3)Following the relationship between the ion concentration difference and the change of electric potential in solution,a set of evaporation efficiency monitoring device(EEMD)was designed in this thesis.The surface modified coconut fiber(SCF)was used as the photothermal material,and the performance test was carried out with the evaporation efficiency monitoring device.The experimental results show ed that the evaporation efficiency of the photothermal material was positively correlated with the change of the electric potential,and the performance of the photothermal material could be monitored based on the real-time change of the electric potential.This design provided a simple real-time monitoring method for the efficient and stable operation of the solar interface evaporation system.In summary,this thesis provided theoretical support and technical guidance for comprehensively solving the problem of salt crystal accumulation and long-term evaporation efficiency monitoring of photothermal materials,and provided new materials and research ideas for the practical app lication of solar interface evaporation. |
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