Preparation And Adsorption And Electrochemical Properties Of Three-dimensional Porous Carbon Materials Based On Cattail Leaves

The coal is used as a raw material for traditional three-dimensional porous carbon materials,which results in high ash content and restrictes mesopore formation.Therefore,agricultural and forestry wastes have become the preferred carbon source for three-dimensional porous carbon materials due to their wide range of sources,low prices,and abundant output.The cattail belongs to the aquatic or marsh perennial herbaceous plants with extensive sources and rapid growth.The upper part of the cattail leaf is flat,the middle is slightly concave and the lower part is gradually raised into a convex shape.The cross section of the cattail leaf is semicircle with large intercellular space and cellular shape.It can be seen that the special internal structure of cattail leaves is beneficial to the formation of pore structure.Although domestic and foreign scholars have continued to develop research on biomass-based three-dimensional porous carbon materials,currently there are few studies on using cattail leaves as the raw material for traditional three-dimensional porous carbon materials.In this paper,cattail leaves were used as carbon source to prepare three-dimensional porous carbon materials by KOH activation method(KPC-X-Y),CO2 activation method(CPC-X-Y),cellulase activation method(CellPC)and white-rot fungus activation method(WRFPC).The specific research contents were as follows:(1)The specific surface area was 10.08 m2·g-1 and the average pore diameter was 6.1 nm when cattail leaves were used as adsorbents.Through single-factor experiments,the optimal dosage of the adsorbent was determined as 0.25 g,the concentration was 50 mg·L-1,the adsorption time was 12 h,and the adsorption environment was neutral.The adsorption by cattail leaves was the spontaneous and exothermic process.(2)The three-dimensional porous carbon materials were prepared by the traditional activation method.The three-dimensional porous carbon material prepared by the KOH activation method had the specific surface area of 1546.56 m2·g-1 and the average pore diameter of 2.2 nm.When the current density was 0.5 A·g-1,the specific capacitance of the electrode was 251.6 F·g-1.Based on the optimal adsorption capacity,the optimum dosage of the adsorbent was 10 mg,the concentration was 50 mg·L-1,the adsorption time was 1.5 h and the adsorption environment was neutral.The specific surface area of the three-dimensional porous carbon materials prepared by the CO2 activation method was 570.03 m2·g-1,and the average pore diameter was 2.3 nm.When the current density was 0.5 A·g-1,the specific capacitance of the electrode was 111.1 F·g-1.Based on the optimal adsorption capacity,the optimal dosage of the adsorbent was 12.5 mg,the adsorption concentration was 50 mg·L-1,the adsorption time was 5 h and the adsorption environment was neutral.(3)The three-dimensional porous carbon materials were prepared by the green activation method.The specific surface area of the three-dimensional porous carbon materials prepared by the cellulase activation method was 115.15 m2·g-1 and the average pore diameter was 2.7 nm.Based on the optimal adsorption capacity,the optimum dosage of the adsorbent was 15 mg,the adsorption concentration was 50 mg·L-1,the adsorption time was 1 h,and the adsorption environment was neutral.The specific surface area of the three-dimensional porous carbon materials prepared by the fungal activation method was 110.67 m2·g-1,and the average pore diameter was 2.9 nm.Based on the optimal adsorption capacity,the optimal dosage of the adsorbent was 20 mg,the adsorption concentration was 50 mg·L-1,the adsorption time was 12 h,and the adsorption environment was neutral.(4)Compared with the the traditional activation method,the carbonization temperature of green activation method was reduced about 50%and the yield was increased by 78.15%,which provided a novel,environmental friendly,simple and cheap method for the preparation of adsorbents in the future.