【作者】 陈悦；

【导师】 郭玉鹏；

【作者基本信息】 吉林大学 ， 物理化学， 2011， 硕士

【摘要】 随着经济,社会,能源,环境等问题日益突出,由环境友好过程,将廉价的天然生物质材料制备成功能化的多孔炭材料,已经引起各国科研工作者的高度关注。生物质是地球上资源非常丰富的天然资源,稻壳是生物质中的一种,并且产量巨大。目前,世界每年稻谷年产量为571亿吨,间接产生140亿吨的稻壳闲置,其中有96%是来自于发展中国家。稻壳的主要成分是纤维素,半纤维素,木质素和矿物盐成分,它们的成分依据稻谷的种类,气候条件,地理环境的影响而发生变化。稻壳通常作为低值能源,在田间堆砌或者燃烧,这样会对环境造成非常不利的影响。大量存在的农副产品废弃物稻壳中含有丰富的固定碳,开发利用稻壳有着重要的意义。将稻壳制备成具有良好吸附性能的活性炭,将会大大减轻其对环境造成的压力。在我组前期工作基础中,已经初步研究以KOH, NaOH, Na2CO3和K2C03为活化剂时,活化时间,活化温度,碱炭比等影响因素对化学活化稻壳产生的影响。先前的研究已经证明,稻壳基多孔炭能够在液相中有效去除多种金属离子和有机分子。它们同样能够应用于电池和电容器的电极材料。本论文基于上述背景,进行以下几方面的研究：(一)我们以稻壳为原料,采用固体NaOH、KOH为活化剂,在高温熔融状态下与稻壳炭化物反应,来研究制备高比表面积多孔炭的工艺,探讨碱金属氢氧化物活化稻壳反应的机理。此外,为了进一步完善碱金属氢氧化物活化稻壳工艺,我们还研究了稻壳活化后处理时温度对稻壳基活性炭结构性能的影响。(二)同时采用一系列的物理化学方法对稻壳基多孔炭进行表征,研究了稻壳基高比表面积多孔炭对甲醛的吸附能力,我们以活性炭和过渡金属盐为原料,通过浸渍法制备了负载型的活性炭为甲醛吸附剂,以活性炭和金属化物的协同作用为基础,进行吸附甲醛方面的研究,找寻稻壳基活性炭在日常生活,空气净化,废水治理方面潜在应用前景。(三)以稻壳为原料,采用固体NaOH、KOH为活化剂,在高温熔融状态下与稻壳炭化物反应,来研究制备高比表面积多孔炭,研究稻壳基活性炭常温常压下储氢性能,为氢能迅速走向实用化奠定基础。(四)研究稻壳基多孔炭的电化学性质,为稻壳基多孔炭在环保、电池、吸附科学及化学修饰电极等领域的应用提供了可靠的理论依据。总之,在本论文以农业废弃物稻壳为原料,制备了高比表面活性炭,测试结果表明稻壳基多孔炭同市售活性炭相比性能优越,体现在空气净化,废水处理,氢能储存,电化学等多个方面。同时本论文还收入了大量关于稻壳基活性炭制备及应用的文献,并对稻壳资源未来的研究方向提出了意见和建议。更多还原

【Abstract】 Recently, much attention has been focused on the use of plant biomass to produce functional carbonaceous materials, encompassing economic, environmental and social issues. Rice husk is a by-product of rice processing. The production of functional activated carbon materials starting from cheap natural precursors using environmentally friendly processes is a highly attractive subject in material chemistry today. The annual world rice production is about 571 million tonnes resulting in approximately 140 million tonnes of rice husk available annually for utilization,96% of which are generated in the developing countries. The major constituents of rice husk are cellulose, hemicellulose, lignin, and mineral components. The content of each of them depends on rice variety, climatic conditions, and even the geographic localization of the culture. Rice husks are usually used as a low-value energy resource, burned in the field, or discarded, which are unfavorable to environment. The processing and transformation of rice husks into activated carbon with good adsorption properties would alleviate problems of disposal and management of these waste by-products, while producing value added products from rice husks for water and wastewater treatment, etc., to expand the carbon market. In our previous studies, activated carbons were prepared from rice husks by chemical activation with KOH, NaOH, Na2CO3 and K2CO3 at different temperatures for various times. The previous researches have demonstrated the ability of rice husk-based activated carbon for many metal ions and organic molecules from aqueous phase adsorption. They were also used as electrode materials for batteries and capacitors.Within the above scope, this study is devoted to the following aspects:(Ⅰ) In this paper, we prepared porous carbon with good adsorptive capacity from rice husks by activation of KOH and NaOH at lower temperatures, and studying the mechanism activation process.The effects of washing temperature on the properties of the porous carbon were studied, and the mechanism and the difference between KOH and NaOH were investigated. (Ⅱ) We studied the rice husk based porous carbon and Commercial grade porous carbon adsorbed formaldehyde by serious of physiochemical measurements. (Ⅲ) The objective of this section is to evaluate the hydrogen storage capacity the hydrogen storage capacity of two types of activated carbons was analyzed hydrogen adsorption isotherms at 298 K and up to 60 atm. Target values that can be achieved for the critical parameters in such a system have been drawn up by the US Department of Energy at room temperature and atmospheric pressure. (Ⅳ) We studied the performance of electrical double layer capacitors with porous carbons derived from rice husk. Different activation conditions can affect the pore structure of the carbons. This paper supplied a method of the utility of rice husk in environment, cell, energy sources, char adsorption and chemical modified electrode and studied the characterization of high surface area porous carbon.The paper (i) presents a critical analysis of rice husks and describes their characteristics, advantages and limitations; (ii) introduces the preparation of porous carbon from rice husks and (iii) discusses various applications involved.In conclusion, a new method was proposed for the comprehensive utilization of bio-resources like rice hull. Many good achievements with important social and economic significance were obtained. In this review, an extensive list of rice husks literature has been compiled. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.更多还原