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KOH活化法制备棉秆基活性炭的研究

2015-09-09耿莉莉张宏喜李学琴

湖北农业科学 2015年14期

耿莉莉 张宏喜 李学琴

摘要:以棉秆为原料,在氮气保护下于400 ℃直接碳化120 min后,以氢氧化钾为活化剂制备棉秆基活性炭,主要考察了碱碳比、活化温度、活化时间等工艺参数对活性炭吸附性能及活化得率的影响。结果表明,制备棉秆基活性炭的最佳工艺条件为碱碳比为2.0,活化温度700 ℃,活化时间90 min,此时制得的活性炭的碘吸附值为1 381 mg/g,亚甲基蓝吸附值为180 mg/g,平均孔径4.42 nm,最可几孔径2.17 nm,活化得率为18.07%。

关键词:棉秆;活性炭;氢氧化钾

中图分类号:S562;TQ351.21 文献标识码:A 文章编号:0439-8114(2015)14-3489-03

DOI:10.14088/j.cnki.issn0439-8114.2015.14.040

Preparation on Activated Carbon from Cotton Stalk by

Chemical Activation with Potassium Hydroxide

GENG Li-li,ZHANG Hong-xi,LI Xue-qin

(Department of Chemistry & Applied Chemistry,Changji University,Changji 831100,Xinjiang,China)

Abstract:Preparation of activated carbon from cotton stalk by chemical activation was investigated in this paper. The plant was firstly carbonized at 400℃ for 120 min and then activated with potassium hydroxide. Effects of alkali-carbon ratio, activation temperature and activation time were studied on the adsorption capacities and yield of the activated carbon. The experimental results showed that the optimum preparation conditions were as follows: the alkali carbon ratio of 2.0, the activation temperature of 700 ℃ and the activation time of 90 min. At this time, the adsorption values of the iodine and the methylene blue,activation yield and the surface area of the activated carbon were 1 381 mg/g, 180 mg/g, 18.07% and 1548 m2/g respectively, the average aperture was 4.42 nm and the most probable aperture was 2.17 nm.

Key words: cotton stalk; activated carbon; potassium hydroxide

活性炭是一种具有石墨微晶结构、孔隙发达、吸附能力很强的吸附剂,由于环境保护的日益重视和对活性炭的结构与性能认识的不断深化,活性炭已成为食品、医药、化学化工、水处理和环保等许多工业中不可替代的产品。近几年,中国活性炭的年产量迅速增加,给生产原料的供应带来了巨大压力[1]。

目前,中国生产活性炭的原料主要是煤、木屑以及果壳等[2-7]。由于煤价格较高,木屑、果壳等数量有限,随着工业技术的发展,用廉价的秸秆为原料制备活性炭越来越受到人们的重视[8-10]。更重要的是与其他活性炭相比,木质活性炭产品具有纯度高、比表面积大、吸附性能好等特点。因此,本研究以棉花秸秆为原料,以KOH为活化剂制备棉秆基活性炭,并对其制备工艺进行探讨。

1 材料与方法

1.1 原料、试剂及仪器

原料:棉花秸秆,取自新疆塔城沙湾县。

药品:KOH、盐酸等所需药品均为分析纯。

仪器:氮气气氛保护箱式电阻炉,宜兴市精艺电炉有限公司;……

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