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    热解自活化法制备竹箨活性炭及其砷吸附性能

    Preparation of activated carbon from bamboo shoot shell by pyrolysis self-activation method and its arsenic adsorption performance

    • 摘要:
      目的 利用竹材加工剩余物竹箨探索一种高效除砷活性炭材料。
      方法 以竹箨为原材料,以微波加热为热源,利用高温热解自活化技术在不同的活化温度和时间下制备竹箨活性炭,通过表征竹箨活性炭的微观形貌、比表面积、孔隙结构、石墨化程度、表面元素和官能团,揭示活化时间和温度等对其微观结构的影响,探讨竹箨活性炭的砷吸附性能,比较不同制备方法下活性炭的比表面积和砷吸附容量的差异。
      结果 活化温度1 050 ℃、活化时间30 min时,竹箨活性炭孔隙结构排列整齐致密,比表面积达到1 251.7 m2/g,孔容为0.697 cm3/g,微孔比表面积比率和微孔孔容比率分别为60.9%和64.0%,平均孔径为0.448 nm,主要由微孔和少量介孔组成,孔径远大于砷酸根离子(AsO4 3−)和亚砷酸分子(H3AsO3)的空间构型尺寸,有利于对As(Ⅲ)和As(Ⅴ)的吸附。反映石墨化程度的R 值为1.340,表面具有丰富的含氧官能团,对As(Ⅲ)的最大吸附量为3.87 mg/g,对As(Ⅴ)的最大吸附量为3.17 mg/g。对比文献中不同活性炭的比表面积和砷吸附容量,竹箨活性炭表现出一定优势。
      结论 适当提高活化温度、延长活化时间有利于表面微孔的形成,从而提高砷吸附容量;但过高的活化温度和过长的活化时间会导致孔隙结构坍塌,减小比表面积和微孔比率,降低砷吸附容量。本研究为高效治理水体砷污染活性炭材料的制备提供了一种简单环保的方法,具有良好的除砷性能。

       

      Abstract:
      Objective This paper aims to explore an efficient arsenic removal activated carbon material using bamboo shoot shell residue from bamboo processing.
      Method Bamboo shoot shell was used as the raw material, while microwave heating was employed as the heat source. Activated carbon from bamboo shoot shell was prepared through catalytic pyrolysis self-activation technique at different activation temperatures and times. The microstructure, specific surface area, pore structure, graphitization degree, surface elements, and functional groups of the activated carbon were characterized to reveal the influence of activation time and temperature on its microstructure. The arsenic adsorption performance of the activated carbon was investigated, and the differences in specific surface area and arsenic adsorption capacity were compared among different preparation methods.
      Result At an activation temperature of 1 050 ℃ and activation time of 30 min, the activated carbon exhibited an orderly and dense pore structure. The specific surface area reached 1 251.7 m2/g, with a pore volume of 0.697 cm3/g. The ratio of micropore specific surface area and the ratio of pore volume were 60.9% and 64.0%, respectively. The average pore diameter was 0.448 nm, primarily composed of micropores and a small amount of mesopores. The pore size was much larger than the spatial configuration dimensions of arsenate ions (AsO4 3−) and arsenous acid molecules (H3AsO3), which facilitated the adsorption of As(Ⅲ) and As(V). The graphitization degree (R) was 1.340, and the surface contained abundant oxygen-containing functional groups. The maximum adsorption capacity for As(Ⅲ) was 3.87 mg/g, while for As(V), it was 3.17 mg/g. Compared with the specific surface area and arsenic adsorption capacity of activated carbon in previous literature, the bamboo strip activated carbon demonstrated certain advantages.
      Conclusion Properly increasing the activation temperature and extending the activation time are beneficial for the formation of surface micropores, thereby enhancing the arsenic adsorption capacity. However, excessively high activation temperature and prolonged activation time can cause the collapse of pore structure, resulting in reduced specific surface area, micropore ratio, and reduce arsenic adsorption capacity. This research provides a simple and environmentally friendly method for the preparation of efficient arsenic removal activated carbon materials, offering promising arsenic treatment performance in water bodies.

       

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