共查询到19条相似文献,搜索用时 140 毫秒
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表面化学改性吸附用活性炭的研究进展 总被引:24,自引:3,他引:24
活性炭表面官能团和杂原子的种类与数量多少决定了活性炭的表面化学性质,而化学性质决定了活性炭的化学吸附特性。通过进行表面氧化、还原以及负载增加或者消除某些基团和活性中心,可以大大改善活性炭对特定吸附质的吸附能力。文章简要介绍了活性炭表面存在的官能团、杂原子和化合物,并对近年来国内外在吸附用活性炭表面化学改性方面的进展进行评述。 相似文献
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通过椰壳活性炭对模拟硫酸盐松节油进行液相吸附脱硫的研究,考察了活性炭的结构和表面化学对活性炭吸附的影响。通过Gaussian03计算模拟油中各化合物的化学硬度,根据软硬酸碱理论解释表面化学对该吸附过程的影响。同时考察了活性炭吸附过程的热力学性质。结果表明,由于吸附体系中的二甲基二硫醚和莰烯的化学硬度相接近,活性炭表面的含氧官能团的变化对吸附性能影响不大,但活性炭比表面积和孔结构的变化对吸附性能的影响较为明显;等温吸附平衡数据符合Freundlich等温吸附模型,热力学数据显示该活性炭吸附过程是一个放热、混乱度降低的自发物理吸附过程。 相似文献
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碳纤维结构的常用表征技术 总被引:4,自引:2,他引:2
本文结合近几年的研究报道,归纳了决定碳纤维性能及应用的两个方面内部体结构和表面结构的一些常用表征技术。碳纤维聚集态的表征主要通过X-射线衍射(广角、小角)、电子衍射;碳纤维形态结构特征常用透射电子显微镜;碳纤维表面结构的表征方法有扫描电子显微镜(SEM),原子力显微镜(ArM),扫描隧道显微镜(STM)以及扫描力显微镜(SFM)。其中,SEM能够看到整个纤维的表面形貌,而AFM、STM、SFM用于表面几个纳米到几百个纳米范围的形貌分析。此外,表面化学状态(表面成分、表面官能团)表征主要依靠X光电子能谱。 相似文献
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对两种国产T800S级碳纤维与进口T800S碳纤维表面特性及其复合材料界面性能的关联性进行了研究。通过扫描电镜(SEM)与原子力显微镜(AFM)对三种碳纤维的表面形貌与粗糙度进行了表征;采用X射线光电子能谱(XPS)对三种碳纤维表面化学官能团比例进行了分峰计算;通过碳纤维表面静态接触角对纤维表面浸润性进行了分析。制备并表征了碳纤维NOL环与单向复合材料的力学性能与微观破坏形貌,通过对比分析确定了影响复合材料界面性能的关键性因素,对复合材料界面性能的进一步提升具有指导意义。 相似文献
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为了改善极性、亲水性卤乙酸(HAAs)分子在非极性、疏水性活性炭上的吸附性能,利用N2等温吸附实验、X射线光电子能谱实验(XPS)、HAAs等温吸附实验等方法,对几种不同产地的活性炭孔隙结构、表面元素形态结构组成,以及HAAs吸附性能进行了研究,考察了活性炭孔结构及含氧官能团对HAAs吸附性能的影响.活性炭表面含氧官能团对HAAs的吸附性能影响显著,当活性炭表面含氧官能团组成较小时,其HAAs吸附能力较强. 相似文献
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用硝酸对活性炭进行了表面改性,并在静态条件下,考察了超声波对改性活性炭吸附Cr(Ⅵ)的影响。结果表明,改性使活性炭表面酸性官能团数量显著增加;有/无超声作用下,活性炭对Cr(Ⅵ)的去除率均随pH值的升高而下降;无超声作用时Cr(Ⅵ)去除率随接触时间的延长持续上升至平衡,而超声作用下去除率先快速上升至近平衡,再小幅下降后又缓慢升至平衡;Cr(Ⅵ)去除率随超声波功率的增大而降低;Freundlich模型能更好描述该吸附过程,超声波的引入对活性炭吸附Cr(Ⅵ)有一定抑制作用。 相似文献
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Renn Arriagada Rafael García 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1999,74(9):870-876
The rate and equilibrium retention of pentachlorophenol, in an aqueous medium, by activated carbons obtained from peach stones and Eucalyptus globulus chips are studied and related to the chemical and textural properties of the adsorbents. E globulus‐activated carbons exhibited a higher pentachlorophenol initial retention rate, due to the higher contribution of the macropores to the porosity of these materials. However, the pentachlorophenol retention rate in activated carbons from peach stones increases to a greater extent than in E globulus with the burn‐off growth, due to the greater development of mesopores in the former. Under the experimental conditions used, the initial retention rate of pentachlorophenol in both adsorbents showed a mixed chemical and diffusional dependence, and the most important variables are the particle size of the adsorbents and the temperature of the medium. Pentachlorophenol equilibrium retention capacity depends on the apparent specific surface area, the presence of carbonylic‐like surface functional groups and the accessibility of the adsorbate to the adsorption sites. The dependence of pentachlorophenol retention capacity with the surface concentration of carbonylic functional groups suggests some chemical interactions between the aromatic pentachlorophenol ring and the carbonylic‐like surface functional groups present in the activated carbons. © 1999 Society of Chemical Industry 相似文献
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Mohammad Asadullah Mohammad Shajahan Kabir Mohammad Boshir Ahmed Nadiah Abdul Razak Nurul Suhada Abdur Rasid Airin Aezzira 《Korean Journal of Chemical Engineering》2013,30(12):2228-2234
Activated carbons have been prepared from jute stick by both chemical and physical activation methods using zinc chloride and steam, respectively. They were characterized by evaluating surface area, iodine number, pore size distribution, and concentration of surface functional groups. The chemically activated carbon largely featured micropore structure, while the physically activated carbon mainly featured macropore structure. The specific surface area of chemically and physically activated carbons was 2,325 and 723 m 2 /g, while the iodine number was 2,105 and 815mg/g, respectively. The concentration of surface functional groups was determined by Boehm titration method, which suggested that different types of surface functional groups are randomly distributed on chemical activated carbons, while it is limited for physical activated carbon. The microporosity along with surface functional groups provided a unique property to chemically activated carbon to adsorb Methylene Blue dye to a large extent. The adsorption of dye was also affected by the adsorption parameters such as adsorption time, temperature and pH. Comparatively, higher temperature and pH significantly facilitated dye adsorption on chemically activated carbon. 相似文献
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Efficient CO2 capture capabilities of activated carbons prepared from natural coal are presented. The preparation method involved simple chemical activation using wet impregnation or dry physical mixing of the raw sample with activating agents like KOH or NaOH. The activated materials were characterized for their structural and textural properties by different analysis techniques. The activated samples exhibited well‐developed porosity, large surface area, and high pore volumes and had other active elements like oxygenated functional groups. These groups modified the surface energy of the resultant samples. The superior performance of the activated carbons was attributed to several factors, including large surface area, presence of narrow micropores, and oxygenated functional groups on the surface. 相似文献
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本文主要研究活性炭表面氧化对其吸附二苯并噻吩性能的影响。将活性炭在不同低温下氧化制得表面氧化活性炭,用静态吸附法进行了二苯并噻吩在初始及氧化活性炭上的吸附等温线,应用Langmuir方程对吸附等温线进行拟合,用漫反射红外谱(DRIFTS)表征活性炭表面含氧基团,用Boehm滴定测定活性炭表面官能团含量,讨论了活性炭表面化学性质对其吸附二苯并噻吩的影响。结果表明:活性炭表面酸性含氧基团对二苯并噻吩的吸附有重要影响,酸性含氧基团越多,其吸附量越大。低温气相氧化活性炭提高了活性炭表面酸性含氧基团,提高了其对二苯并噻吩的吸附。氧化温度越高,其表面含氧基团含量越多,其对二苯并噻吩的吸附量也越大。Langmuir吸附等温线可适用于描述二苯并噻吩在活性炭表面上的吸附。 相似文献
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Croswel Aguilar Rafael García Gabriela Soto-Garrido Renán Arraigada 《Topics in Catalysis》2005,33(1-4):201-206
The catalytic wet air oxidation (CWAO) of methyl and dimethylamines was studied. A commercial peach stones activated carbon and its oxidized and reduced forms were used as catalysts. The observed catalytic behavior is related to the presence of oxygenated surface functional groups on the activated carbons. The N-compounds were selectively oxidized to nitrogen, water and carbon dioxide using these activated carbon catalysts. It is proposed that the quinonic surface groups are responsible for the selective catalytic oxidation of these amines. Carboxylic, lactonic and anhydride groups strongly adsorb the amine compounds producing inhibition of the catalytic activity of the activated carbon in the CWAO process. 相似文献
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分别用1 mol·L-1硝酸、1 mol·L-1盐酸、1 mol·L-1硫酸对商业活性炭进行浸渍改性。采用比表面积及孔径分析仪、Boehm滴定、傅里叶转换红外光谱(FTIR)对活性炭的物化性质进行表征。以甲苯、甲醇为吸附质,在283 K下进行了固定床吸附实验。研究表明:酸改性能去除表面碱性基团,显著增加表面酸性含氧官能团的含量;酸改性活性炭的吸附量与其比表面积、总孔容、微孔孔容、表面总酸性官能团呈现出良好的线性关系;Langmuir方程比Freundlich方程更加适合描述甲苯、甲醇在活性炭上的吸附;甲醇在活性炭上为物理吸附,甲苯在活性炭上以物理吸附为主,与表面官能团之间的化学键作用能增强甲苯吸附量;甲苯、甲醇在活性炭上的微孔有效扩散系数的大小顺序为:AC-N>AC-1>AC-S>AC-C;并且甲醇的微孔有效扩散系数大于甲苯。 相似文献
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Chemical Surface Characterization of Activated Carbons by Adsorption Excess of Probe Molecules 下载免费PDF全文
Activated carbons are one of the most common industrial adsorbents in liquid‐phase applications. It is known that the surface groups of the activated carbon can have a significant influence on the adsorption process from the liquid phase. Therefore, it is desirable to measure surface groups on activated carbons. This opens up the possibility to use group‐contribution methods to model and predict adsorption isotherms. An idea is presented to characterize the inner surface of activated carbons by three types of surface groups: aromatic, polar, and nonpolar surface groups. The amounts of these surface groups were calculated from excess adsorption isotherms of probe molecules on ten activated carbons. This lays the groundwork for further simulation studies of liquid‐phase adsorption using group‐contribution methods. 相似文献