| Graphene materials have a good performance in the field of pollutants adsorption in water and solar desalination for their special two-dimensional nanosheet structure and excellent physical and chemical properties.However,pure graphene water treatment materials still have some shortcomings,such as complex preparation process,harsh preparation conditions,uncontrollable structure,difficulties in industrial production and so on.Based on chemical crosslinking between graphene and polyvinyl alcohol,the graphene/polyvinyl alcohol porous materials were prepared and optimized in this paper.The porous materials were characterized by SEM,XPS,XRD,Raman,MIP,BET,etc.Their applications in dye adsorption and purification in water and solar water evaporation were studied.The application of two kinds of materials in dye adsorption and solar vapor generation were studied respectively.The research contents and experimental results are as follows:Reduced graphene oxide was obtained by heating the mixture of graphene oxide dispersion and tannic acid powder at first.After testing and characterization,it was found that the longer the reaction time with tannic acid lasted,the higher the reduction degree of reduced graphene oxide was.The graphene/polyvinyl alcohol adsorption porous materials were prepared by crosslinking graphene oxide and reduced graphene oxide dispersion with polyvinyl alcohol solution.The result of the static adsorption test showed that the higher the degree of reduction of reduced graphene oxide was,the better the adsorption performance of porous materials had,the capacity of methylene blue was 66.2mg g-1.The graphene/polyvinyl alcohol porous materials for solar vapor generation were prepared by crosslinking between reduced graphene oxide and polyvinyl alcohol.After tests,it was found that the reduced graphene oxide/polyvinyl alcohol porous materials adsorbed nearly 100%of light at 200nm-2500nm,and it had more obvious acceleration effect on solar vapor generation than graphene oxide/polyvinyl alcohol porous materials.The average evaporation rate of water covered with it was 3.15 times that of the water uncovered within 1h.The preparation process of graphene/polyvinyl alcohol porous materials for solar vapor generation was further studied and optimized,it was found that more reduced graphene oxide added in unit volume,the better the solar vapor generation performance of materials showed.The optimized porous material had three kinds of pore structures:micropores,mesopores and macropores,and the content of micropores and mesopores was relatively high,and the content of macropores was relatively low.After solar vapor generation experiment,it was found that the average evaporation rate of water covered by the optimized porous material was 4.33 times that of the water uncovered.The graphene/polyvinyl alcohol porous materials in this paper not only have excellent properties,but also are simple in preparation,low in cost and easy to batch production. |
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