摘要
采用高温热处理法去除活性炭表面含氧官能团,并通过化学浸泡法分别将酚羟基和羧基添加到活性炭表面。利用氮气吸附-脱附、X射线衍射分析、X射线光电子能谱法对改性前后活性炭进行表征。研究发现:经高温热处理的活性炭比表面积增大为1139m2/g,孔径集中分布于1nm以下;热处理后活性炭内部晶格结构更加完整。经过化学改性后,酚羟基和羧基均可以一定比例负载到活性炭表面,且比表面积随着负载量增多而下降。对气态汞的吸附实验表明:经高温热处理的样品对气态汞的吸附能力与原始活性炭相比有所下降:当达到吸附饱和时,原始活性炭的吸附量为306.55μg/g,而经热处理的样品的吸附量是243.5μg/g;负载羧基的活性炭样品,其吸附容量高达865.3μg/g;负载酚羟基样品的吸附容量为133.1μg/g。由此得出结论:活性炭表面的含氧官能团对其吸附气态汞有重要影响,其中羧基的存在有利于对气态汞的吸附,而酚羟基的存在对气态汞的吸附不起促进作用。
The oxygen- containing groups on activated carbon surfaces could be removed by heating in nitrogen atmosphere （1 000℃ ） . After heat treatment, carboxyl and phenol groups were added separately to the surface of activated carbons by chemical immersion method. And the surface physicalchemical properties of these carbons were characterized by nitrogen adsorptiondesorption, X- ray diffraction and X- ray photoelectron spectroscopy. It was found that the BET surface area of the heattreated samples was increased to 1 139 m2/g, meanwhile they bad more ordered structures and more narrow pore size distribution which was smaller than 1 nm. After chemical modification, phenol and carboxyl groups could be loaded on the surface of activated carbons in a certain proportion, and the BET surface area decreased as the amounts of phenol and carboxyl groups increased. The experiments were conducted to evaluate the capability of original activated carbons, heat- treated and modified carbons on the adsorption of mercury vapor at room temperature. The results show that there is some decrease of mercury adsorption for heat- treated samples compared to original activated carbons. When it reaches saturation, the mercury adsorption capacity of original activated carbons is 306. 55 μg/g, while the capacity of heat - treated activated carbons is 243.5μg/g; the capacity of carboxyl- loaded activated carbons reaches 865.3 μg/g, while the capacity of phenol- loaded activated carbons is 133.1μg/g. The assumption is that the oxygen-containing functional groups indicate significant effect on mercury adsorption ability of activated carbon. And the carboxyl groups are beneficial to the mercury adsorption, while the phenol groups may have no effect on mercury adsorption.
出处
《炭素技术》
CAS
CSCD
2009年第5期1-6,共6页
Carbon Techniques
基金
国家自然科学基金项目(20707018)
福建省科技重点项目(2008I0024)
福建省青年科技人才创新基金项目(2006F3118)
关键词
改性活性炭
表面官能团
汞吸附
Modified- activated carbon
surface functional groups
mercury adsorption
