活性炭自吸附单层改性增强锌离子混合超级电容器性能

[Objective]Activated carbon is currently the most widely used material in wastewater purification,but it still carries toxic pollutants on its own after use.The pollutants are covered by a monolayer in activated carbon through self-adsorption in pore channels,which can enhance its electrochemical performance for constructing high-performance zinc-ion hybrid supercapacitors,providing a feasible carbon material preparation system for comprehensively promoting the resourceful use of agricultural and forestry biomass and enhancing the energy storage capacity of carbon-based supercapacitors.[Method]Porous carbon was prepared from Eucommia ulmoides Oliver wood powder using microwave irradiation technology combined with physical-chemical synergistic activation method,which was used for the adsorption of Cr(VI),methylene blue,Cu(II),Co(II),and Ag(I)in wastewater,and adsorption isotherms with different temperatures were used to determine the adsorption capacity of the porous carbon for various pollutants at different initial concentrations,which was recovered by centrifugation and lyophilisation.The physicochemical properties of the porous carbon materials were characterised using BET,XRD,FTIR and XPS techniques,the electrochemical properties of the recovered activated carbon were tested in a three-electrode aqueous supercapacitor system,and a high-performance zinc-ion hybrid supercapacitor was constructed to test the zinc storage performance,and the physicochemical properties of activated carbon electrodes in the charging and discharging state were characterized using non-in-situ XRD,Raman and XPS techniques,to The physicochemical characterisation of the activated carbon electrodes in the charged and discharged state using non-in-situ XRD and XPS techniques was carried out to reveal the enhancement mechanism of wastewater pollutants on the zinc storage performance.[Result]The specific surface area of the porous carbon(PC)prepared by the physical-chemical co-activation method reached 1489.86 m2/g with a mesopore ratio of 58%,the specific surface area and pore size of the activated carbon after adsorption of the pollutants decreased,and the adsorption isotherms were in accordance with the Langmuir isotherm model,and the results of the SEM and TEM-EDX images also indicated that the pollutants were successfully modified in the activated carbon,and the pore internal channels achieved a homogeneous monolayer coverage.The results of the GCD method in the three-electrode aqueous supercapacitor system showed that the electrochemical specific capacities of the activated carbon adsorbed with Cr(VI),methylene blue,Cu(II),Co(II),and Ag(I)were increased by 115,123,146,84,and 242%,respectively,and the internal resistance of electrochemical transport was significantly reduced compared with that of PC.The activated carbon after PC and adsorption of Cr(VI),methylene blue,Cu(II),Co(II)and Ag(I)were prepared into electrode sheets with zinc storage specific capacities of 35 mAh g-1,396.35 mAh g-1,38 mAh g-1,249 mAh g-1,45 mAh g-1,and 564 mAh g-1,respectively.By analysing the results of the pseudo capacitance contribution It was found that Cr(VI)pollutant was able to significantly promote the pseudocapacitance generation at different scanning rates,while Ag(I)pollutant was able to improve the electrical conductivity and ion transport kinetic properties,which further contributed to the diffusion-controlled capacitance generation behaviour.[Conclusion]Finally,the recycled activated carbon can be used to construct high-performance zinc-ion hybrid supercapacitors with excellent economic feasibility,which will provide theoretical and technological support for the high-value utilisation of biomass resources and the efficient operation of the energy storage system under the background of"dual-carbon".