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由于具有很大的吸附容量,多孔炭材料是优良的吸附剂。笔者试图比较海枣核分别经CO2活化和磷酸活化所制活性炭的结构和吸附性能。活化过程和工艺条件对炭的物理化学性质影响较大,根据文献报道的结果选取了优化的工艺参数。基于氮气吸附等温线、SEM、FT-IR等分析结果,评估了活性炭的结构特征,吸附性能则由亚甲蓝吸附值表示。CO2活化得到了微孔活性炭,产率为44%、BET比表面积是666 m2·g-1;磷酸活化得到了产率为14.8%的中孔活性炭,BET比表面积为725 m2·g-1。CO2活化活性炭的平均孔径是1.51 nm,磷酸活化活性炭的则为2.91 nm。活性炭的亚甲蓝吸附等温线分别用Langmuir等温线和Freundlich等温线进行了验证,在优化工艺条件下制备的CO2活化炭和磷酸活化炭的亚甲蓝w单分子吸附容量分别为110 mg·g-1和345 mg·g-1。然而,磷酸活化产生的亚甲蓝吸附值最高达455 mg·g-1。
Porous carbon materials are excellent adsorbents due to their large adsorption capacity. The author attempts to compare the structure and adsorption properties of activated carbon prepared by CO2 activation and phosphoric acid activation respectively. The activation process and process conditions have a great influence on the physico-chemical properties of carbon, and the optimized process parameters are selected according to the results reported in the literature. The structural characteristics of the activated carbon were evaluated based on the nitrogen adsorption isotherms, SEM, FT-IR analysis, and the adsorption performance was represented by the methylene blue adsorption value. Activated carbon obtained microporous activated carbon, the yield was 44%, the BET specific surface area was 666 m2 · g-1; phosphoric acid activated to obtain a yield of 14.8% mesoporous activated carbon, BET specific surface area of 725 m2 · g-1. The average pore size of activated carbon activated carbon was 1.51 nm and that of activated carbon activated by phosphoric acid was 2.91 nm. The methylene blue adsorption isotherms of activated carbon were respectively verified by Langmuir isotherm and Freundlich isotherm. The single molecule adsorption capacities of methylene blue (WCO) activated carbons and activated carbons of activated carbon prepared under optimal conditions were 110 mg · g -1 and 345 mg · g -1. However, the activation of phosphoric acid produced methylene blue up to 455 mg · g-1.