Structure Design And Performance Research Of Solar Vapor Generator Based On Cellulose Gel

Solar vapor generation technology extracts fresh water from a variety of raw water by using green and clean solar energy,which can alleviate the energy crisis and the shortage of fresh water at the same time.In this thesis,cellulose nanofibers（CNF）/polylactic acid（PLA）composite aerogel was prepared using the Pickering emulsion technology stabilized by CNF.On this basis,the morphology of the polymer photothermal particles was micro-designed by in-situ polymerization technology.A series of cellulose-based gels with different surface morphologies were prepared as solar vapor generator.In addition,the evaporation performance has been optimized through structural design and wind energy.Finally,we explored its purifying effect on a variety of raw water.The main results are as follows:（1）In-situ polymerization was used to construct CNF/PLA/Polyaniline（PANI）hybrid aerogels.By adjusting the molar concentration ratio of aniline monomer and ammonium persulfate oxidant,the effect of nanoclusters,nanorods and nanospherical PANI on the photothermal conversion ability of hybrid aerogels was studied.Among these aerogels,the aerogels grown by PANI nanoclusters have light absorption of 97%,with surface temperature up to approximately 105°C under an irradiation of 1 Sun.The evaporation rate of the hybrid aerogel to Lijiang water reached 1.58 kg m^-2 h^-1,corresponding an efficiency of 90%.Finally,the hybrid aerogel shows strong purification ability for various types of raw water.（2）The microscopic morphology of CNF/PLA/PANI hybrid aerogel is adjusted by changing the concentration and type of doped acid,and the macroscopic morphology of the aerogel is controlled by introducing the hemispherical recess structure into the surface of the aerogel through a simple mold.The effects of the micro-morphology and macro-morphology structure on the light absorption performance of hybrid aerogels and the suppression of heat radiation loss were further studied.Studies have shown that the interface design can enhance light absorption and recover part of the heat loss.A higher evaporation rate of 1.65 kg m^-2 h^-1 with a steam generation efficiency of 94.6%was achieved under the irradiation of 1 Sun.Finally,the hybrid aerogel has strong purification ability for various types of raw water,and are promising in terms of their application potential in the field of energy conversion.（3）An aero-hydrogel with hierarchical porous structure was constructed by cross-linking hydrogel and aerogel.The promotion effect of hierarchical porous structure on evaporation performance has been studied.The aero-hydrogel has a light absorption rate of 98%,and can effectively reduce the enthalpy of water evaporation,while having stable self-floating properties and thermal management capabilities.After further structural optimization,the aero-hydrogel reached an evaporation rate of2.16 kg m^-2 h^-1 under 1 Sun irradiation with an efficiency of 93.6%.In addition,the promotion effect of wind on evaporation was revealed,an evaporation rate of 5.67 kg m^-2 h^-1 was achieved at a wind speed of 3 m s^-1.Finally,the aero-hydrogel achieves high-purity purification of various raw water,showing great application potential.（4）CNF/PLA/polydiaminonaphthalene（PDAN）hybrid aerogels with two different PDAN morphologies were prepared by adjusting the in-situ polymerization process.Among them,the molecular chain of PDAN-1 in which nanorods and nanospheres coexist has more N-H bonds.The wet CNF/PLA/PDAN-1 can absorb 95%of visible light,and its surface temperature can reach 80°C under 1 Sun irradiation.The evaporation rate of brine is 1.50 kg m^-2 h^-1 corresponding to an efficiency of 90%.While producing clean water,it can also reduce silver ions.This hybrid aerogel containing silver element exhibits antibacterial activity against Staphylococcus aureus,which puts forward a new idea for the treatment of silver-containing waste liquid.