生物质基炭材料的制备及性能研究

发布时间：2018-09-19 17:53

【摘要】：以天然可再生的生物质为原料制备炭材料,不仅可减少人类对化石能源的需求,还可缓解因焚烧生物质而引起的环境污染问题。本文以核桃壳和柚皮为前躯体,在稀硫酸的催化作用下,采用一步水热炭化的方法制备水热炭,并考察其对六价铬的吸附性能;采用KOH活化水热炭制备多孔炭,并研究其在超级电容器中的电化学性能。主要内容如下:(1)核桃壳水热炭和柚皮水热炭的最合适的制备条件为分别在180℃、190℃下水热12h,此时水热炭收率分别为50.69%、50.13%,碳含量分别为66.26%、60.22%;比表面积分别为21m2/g、79 m2/g,孔径主要分布在2~24nm之间,是典型的介孔材料;水热炭主要由粒径大小不一的炭微球组成,表面有很多含氧官能团。(2)水热炭在吸附六价铬的过程中受pH影响较大,酸性条件下效果较好;随水热炭加入量增加,吸附率增加,吸附量先增加后减小;随六价铬浓度升高,吸附量逐渐增加,吸附率先增加后减小;吸附平衡时,核桃壳水热炭和柚皮水热炭对六价铬的吸附率分别为98.32%、99.03%;吸附动力学和等温吸附数据研究结果表明,水热炭的吸附过程符合准二级动力学模型和Freundlich模型。(3)随碱碳比、活化温度的增加,多孔炭的比表面积和总孔容先增加后减小,中孔率逐渐增加;同常规热解炭化活化制备的炭材料相比,核桃壳多孔炭和柚皮多孔炭的的比表面积分别增加了13.62%、16.79%,总孔容分别增加了14.37%、11.43%;多孔炭均由许多表面光滑的炭微球和不规则的块状结构组成;其形成分为低温“汽化”和高温“活化”两个阶段。(4)核桃壳多孔炭和柚皮多孔炭作为电极材料,在3mol/L KOH电解液中具有良好的电容特性,质量比电容最大分别可达284F/g、260F/g,同常规热解炭化活化制备的炭材料相比,质量比电容分别增大了36.54%、20.37%。
[Abstract]:Using natural renewable biomass as raw material to prepare carbon materials can not only reduce human demand for fossil energy but also alleviate the environmental pollution caused by burning biomass. In this paper, using walnut shell and pomelo peel as precursors, hydrothermal carbon was prepared by one-step hydrothermal carbonization under the catalysis of dilute sulfuric acid, and its adsorption property for hexavalent chromium was investigated. Porous carbon was prepared by KOH activated hydrothermal carbon. The electrochemical performance of the supercapacitor was studied. The main contents are as follows: (1) the most suitable conditions for the preparation of hydrothermal carbon from walnut shell and pomelo peel are as follows: water heating at 180 鈩，

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