Ag+及其配合物在活性炭上吸附行为研究

研究了配位体和氧化改性对活性炭吸附Ag^ 及其配合物的影响以及银在活性炭表面的分布特征。结果表明：(1)活性炭对Ag^ 的吸附非常快,且不受离子强度的影响．但当Ag^ 形成[Ag(NH3)2]^ 和[Ag(S2O3)2]^3-后在活性炭上吸附性能下降,氨水浓度增加对[Ag(NH3)2]^ 的吸附没有影响,而还原性的Na2S2O3浓度增加使[Ag(S2O3)2]^3-的吸附下降。(2)银主要分布在活性炭的外表面,Ag^ 浓度和吸附时间不同将导致银颗粒的分布及粒径也不同,合理控制Ag^ 浓度和吸附时间,就可以在活性炭表面负载纳米金属银．(3)活性炭氧化改性不利于Ag^ 和[Ag(S2O3)2]^3-的吸附,却有利于[Ag(NH3)2]^ 的吸附。     

通过氧化改性提高载银活性炭的抗菌性能

使用浓HNO3和浓H2O2对活性炭进行常温氧化改性,用FTIR和N2吸附法对活性炭进行表面分析,用AAS、SEM、XRD研究银在活性炭表面的吸附和分布特征,并研究了载银活性炭的抗茵性能.结果表明,活性炭经浓HNO3常温改性后,比表面积提高,而经浓H2O2常温改性后,比表面积略有下降,但都使活性炭表面含氧基团增加.改性后,活性炭表面增加的含氧基团为[Ag(NH3)2] 的还原吸附提供更多的活性点,使银的吸附量增大5倍多,银颗粒更加密集,大小更加均一.研究表明,载银活性炭具有明显的抗茵作用,其中对金黄色葡萄球菌的杀灭效果优于对大肠杆菌的杀灭效果,氧化改性使载银活性炭抗茵作用显著增强,其中硝酸改性现象更加明显.     

杂多酸在活性炭上的固载化Ⅱ.几种国产活性炭的表面性质对…

本文研究了四种具有Ｋｅｇｇｉｎ结构的杂多酸在五种国产改性活性炭载体上的吸附作用。实验结果表明，不同的杂多酸在活性炭上的吸附量不同的，并且不同的活性炭对杂多酸的吸附等温线和吸附能力出不同。活性炭的表面化学性质显著地影响杂多酸在其上吸附。     

杂多酸在活性炭上的固载化 Ⅱ．几种国产活性炭的表面性质对杂多酸吸附作用的影响

本文研究了四种具有Ｋｅｇｇｉｎ结构的杂多酸在五种国产改性活性炭载体上的吸附作用．实验结果表明，不同的杂多酸在活性炭上的吸附量是不同的，并且不同的活性炭对杂多酸的吸附等温线和吸附能力也不同．活性炭的表面化学性质显著地影响杂多酸在其上的吸附。     

活性炭电极的改性及对Co2+,Mn2+和Ni2+的电吸附性能

以商用活性炭(AC)为原料,分别采用磷酸和氢氧化钠改性的方法制备了两种不同的改性活性炭电极材料.采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、 Brunauer-Emmett-Teller(BET)测试、傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)等手段以及电化学分析方法,对改性前后活性炭材料的表面性质和电化学性能进行了探究.结果表明, H3PO4改性使活性炭的孔隙分布更加密集, NaOH改性使活性炭表面的孔隙结构更加清晰均匀; H₃PO₄和NaOH改性均使活性炭的比表面积增加.循环伏安测试结果表明,改性前后活性炭电极在低扫描速率下均具备良好的双电层特性,并且两种改性处理均能提高活性炭电极的比电容;当扫描速率为5 mV/s时,未改性、 H₃PO₄以及NaOH改性活性炭电极的比电容分别为36.51, 77.25和85.19 F/g.电吸附实验结果证明,两种改性活性炭电极对Co²⁺, Mn²⁺和Ni²⁺均有较好的去...     

改性活性炭热反应安全性研究

针对活性炭吸附VOCs过程的安全性问题进行了研究,采用咪唑-脯氨酸离子液体对活性炭进行改性,优化吸附性能。以典型的甲苯气体为例,讨论了改性前后活性炭结构的变化对甲苯吸附性能的影响,并探索了改性前后活性炭的热反应安全性。研究结果表明:咪唑-脯氨酸改性活性炭表面的孔隙数量增多、孔径变大、含氧官能团增加、比表面积和体积增大。改性活性炭对甲苯的吸附量78 mg·g~(-1)是改性前活性炭吸附量36.03 mg·g~(-1)的2.17倍,吸附能力明显提升;粒径为51μm和111μm的两种改性活性炭的自燃温度比未改性活性炭的自燃温度分别提高了22.4℃和19.4℃且到达自燃温度所需时间分别延长了11.17 h和0.75 h。改性活性炭所需活化能为47.32kJ·moL~(-1),热稳定性优于未改性活性炭。     

活性碳纤维的结构修饰及其吸附氙性能的研究

活性炭纤维对氙的吸附容量与其孔结构密切相关，为了提高活性炭纤维对氙气的吸附容量，本文分别用亚甲基蓝、对硝基苯酚等有机物，或氯化钠、碘等无机化合物填充的方法修饰活性炭纤维的孔结构；以及利用高锰酸钾或硝酸等氧化处理修饰活性炭纤维的表面化学性质，同时，利用低温氮等温吸附表征了这些改性活性炭纤维的孔结构，以及通过光电子能谱表征了改性活性炭纤维的表面化学结构，上述化合物充填或氧化改性活性炭纤维对氙的吸附性能的研究结果表明，适量化合物填充，或合适浓度硝酸对活性炭纤维的表面处理，可以有效地修饰活性炭纤维的孔结构或改变活性炭纤维表面对氙的亲和力。因而可有效地提高改性活性炭纤维对氙的吸附容量。     

双偶极半菁衍生物／H4SiW12O40自组装多层膜的研究

通过交替吸附H_4SiW_(12)O_(40)和双偶极半菁衍生物制备了一个新颖的无机- 有机杂化自组装多层膜。紫外可见光谱和X射线衍射研究证实了半菁衍生物 /H_4SiW_(12)O_(40)多层膜可被均匀沉积厚达至少12层，具有平均膜厚5.3nm(半菁 阳离子层加SiW_(12)O_(40)~(4-)层)的二维有序结构，膜中半菁衍生物与H_4SiW_ (12)O_(40)间发生了较强的电荷转移作用。循环伏安研究表明，薄膜具有较好的电 化学活性。     

活性炭的高温脱氧改性及其床层对全氟异丁烯的吸附动力学研究

在N2气保护下对颗粒状活性炭进行了不同温度(400—800 ℃)下的高温改性, 考察了不同的空气流湿度(30%—80% R.H.)下全氟异丁烯(PFIB)在活性炭床层中的吸附穿透行为. 利用Wheeler方程对穿透数据进行了处理, 并采用线性平衡吸附体系的动力学模型对床层的穿透实验数据进行了关联. 结果表明, 基炭经高温改性后, 活性炭的孔隙结构没有明显变化, 表面含氧量随处理温度的提高而减少, 在高湿条件下对全氟异丁烯的选择性吸附能力显著提高, 活性炭床层可使PFIB的防护时间延长. 各种实验条件下的理论穿透曲线与实验值数据吻合, 可以利用线性平衡吸附体系的动力学模型来预示PFIB在活性炭层中的穿透行为, 进行防毒面具的滤毒罐参数的选取和设计.     

活性炭表面含氧基团对苯酚吸附平衡及动力学的影响

煤基活性炭分别用烧失处理和HNO3氧化处理后得到不同表面性质的活性炭,采用X射线光电子能谱(XPS)、N2吸附、酸碱滴定及零电荷点(pHPZC)对活性炭表面性质及孔结构进行表征,研究了活性炭表面性质对苯酚吸附平衡和吸附动力学影响.经HNO3氧化后,活性炭表面含氧基团显著增加,烧失处理后,表面含氧基团尤其是羧基显著减少.苯酚最大平衡吸附量随活性炭表面含氧基团的增多而减少,吸附速率常数与碳表面含氧基团的量呈正相关,而吸附活化能与活性炭在一定吸附条件下表面所带电荷多少相关.随着活性炭表面含氧基团增多,吸附活化熵增大(负值减小),苯酚在活性炭表面排列的有序性减小.静态吸附与动态吸附实验结果都表明:在含氧基团较少而碱性更强的活性炭上,发生化学吸附的程度更大.     

活性炭表面固载十二硅钨酸的表征

活性炭表面固载十二硅钨酸的表征王新平，叶兴凯，吴越（中国科学院长春应用化学研究所，长春１３００２２）关键词硅钨酸，杂多酸，活性炭，负载型催化剂，表征由于杂多酸的优异催化性能，近年来其固载化的研究深受人们的关注［１］．活性炭是固载杂多酸较好的载体之一［...     

Water vapor adsorption and microporous structure of carbon adsorbents. 18. Effect of surface chemistry of activated carbons on water vapor adsorption

This investigation has been devoted to a study of the chemical composition of the surfaces of activated carbons. A study has been made of the way in which changes in the surface chemistry of a series of carbons, as a result of heat treatment, affects the nature of their adsorption of water vapor. A differentiation has been made between oxygen-containing groups found on the surface of activated carbons before and after their heat treatment. It has been established that the original adsorption centers, which play a determining role in water vapor adsorption by activated carbons, comprise functional groups like strongly acidic free hydrogen ions, carboxylic and phenolic groups, situated on on the pore surface of the activated carbons. The number of these functional groups on the pore surface of the activated carbons has been correlated with the parametera ₀ (the number of original adsorption centers) in the isotherm equation for water vapor adsorption. The relative pressure corresponding to the formation of an adsorption layer on the surface of the activated carbons has been shown to depend on the number of original adsorption centers, the acidic functional groups.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 35–40, January, 1991.     

Pore structure and adsorption performance of the KOH-activated carbons prepared from corncob

Carbonaceous adsorbents with controllable surface area were chemically activated with KOH at 780 degrees C from chars that were carbonized from corncobs at 450 degrees C. The pore properties, including BET surface area, pore volume, pore size distribution, and mean pore diameter of these activated carbons, were characterized by the t-plot method based on N(2) adsorption isotherms. Two groups are classified according to the types of adsorption/desorption isotherms. Group I corncob-derived activated carbons, with KOH/char ratios from 0.5 to 2, exhibited BET surface area ranging from 841 to 1221 m(2)/g. Group II corncob-derived activated carbons, with KOH/char rations from 3 to 6, showed high BET surface areas, from 1976 to 2595 m(2)/g. From scanning electron microscopic (SEM) results, the surface morphology of honeycombed holes on corncob-derived activated carbons was significantly influenced by the KOH/char ratios. The adsorption kinetics of methylene blue, basic brown 1, acid blue 74, 2,4-dichlorophenol, 4-chlorophenol, and phenol from water at 30 degrees C were studied on the two groups of activated carbons, which were suitably described by two simplified kinetic models, pseudo-first-order and pseudo-second-order equations. The effective particle diffusivities of phenols and dyes at the corncob-derived activated carbons of group II are higher than those of ordinary activated carbons. The high-surface-area activated carbons were demonstrated to be promising adsorbents for pollution control and for other applications.     

几种植物基活性炭材料的表面结构与吸附性能比较——(II)表面化学结构与吸附性能研究

用X-射线光电子能谱对3种植物基活性炭材料:椰壳活性炭 (CAC4)、剑麻茎基活性炭(SSAC)和剑麻基活性碳纤维 (SACF) 的表面化学结构进行了表征,并研究和对比了它们的吸附性能,包括对碘、苯酚和亚甲基蓝的液相吸附性能,对有机蒸汽的吸附性能以及对Au3+的还原吸附性能等。结果表明,3个样品表面均含有多种含氧官能团,吸附能力SACF>SSAC> CAC4。样品的吸附性能主要取决于自身孔结构,与其表面化学结构也有密切的关系。     

Pore structure and surface properties of chemically modified activated carbons for adsorption mechanism and rate of Cr(VI)

Effects of hydrochloric acid and sodium hydroxide treatments of activated carbons (ACs) on chromium(VI) reduction were studied. The surface properties were determined by pH, acid-base values, FT-IR, and X-ray photoelectron spectrometer (XPS). And the porous structure of the activated carbons was characterized by adsorption of N(2)/77 K. The Cr(VI) adsorption experiments were carried out to analyze the influence of porous texture and surface properties changed by the chemical surface treatments of ACs on adsorption rate with carbon-solution contact time. From the experimental results, it was observed that the extent of adsorption and reduction processes depends on both microporous structure and functional groups. And the adsorption of Cr(VI) ion was more effective in the case of acidic treatment on activated carbons, resulting from the increases of acid value (or acidic functional group) of activated carbon surfaces. However, basic treatment on activated carbons was not significantly effective on the adsorption of Cr(VI) ion, probably due to the effects of the decrease of specific surface area and basic Cr(VI) in nature.     

杂多酸在活性炭表面含氧基团上的化学键合作用

杂多酸作为一种新型多功能催化剂，近年来匕成为催化领域的研究热点之一［’l杂多酸在均相对许多反应表现出优异催化性能，正逐步为工业催化过程所采用问．较早的研究表明，吸附在活性炭上的杂多酸可部分牢固地存留干其表面不被溶脱，并可保持一定的催化活性＊．关干活性炭表面上杂多酸吸附作用的本质，一直没有明确的结论．本文通过吸附在活性炭表面和溶于含氧有机溶剂中杂多酸的光谱特征，探讨活性炭表面上杂多酸吸附的化学键合作用．1实验部分（且）药品：杂多酸均为市售商品，未经任何处理，直接使用．硅钨酸分子式为儿出风。0。。‘24…     

Cadmium ion adsorption on different carbon adsorbents from aqueous solutions. Effect of surface chemistry, pore texture, ionic strength, and dissolved natural organic matter

Adsorption of Cd(II) species at pH = 5 was studied on three carbon adsorbents: granular activated carbon, activated carbon fiber, and activated carbon cloth. As-received and oxidized adsorbents were used. Cd(II) adsorption greatly increased after oxidation due to the introduction of carboxyl groups. The use of a buffer solution to control the pH introduced some changes in the surface chemistry of carbons through the adsorption of one of the compounds used, biphthalate anions. The increase in ionic strength reduced Cd(II) uptake on both as-received and oxidized carbons due to a screening of the electrostatic attractions between the Cd(II) positive species and the negative surface charge, which in the case of as-received carbons derived from the biphthalate anions adsorbed and in the oxidized ones from the carboxyl groups. Tannic acid was used as a model compound for natural organic matter. Its adsorption was greatly reduced after oxidation, and most of the carbon adsorbents preadsorbed with tannic acid showed an increase in Cd(II) uptake. In the case of competitive adsorption between Cd(II) species and tannic acid molecules, there was a decrease in Cd(II) uptake on the as-received carbon whereas the contrary occurred with the oxidized carbons. These results illustrate the great importance of carbon surface chemistry in this competitive adsorption process. Finally, under all experimental conditions used, when the adsorption capacity of carbons was compared under the same conditions it increased in the following order: granular activated carbon < activated carbon fiber < activated carbon cloth.     

Adsorption of NH3 onto activated carbon prepared from palm shells impregnated with H2SO4

Adsorption of ammonia (NH3) onto activated carbons prepared from palm shells impregnated with sulfuric acid (H2SO4) was investigated. The effects of activation temperature and acid concentration on pore surface area development were studied. The relatively large micropore surface areas of the palm-shell activated carbons prepared by H2SO4 activation suggest their potential applications in gas adsorption. Adsorption experiments at a fixed temperature showed that the amounts of NH3 adsorbed onto the chemically activated carbons, unlike those prepared by CO2 thermal activation, were not solely dependent on the specific pore surface areas of the adsorbents. Further adsorption tests for a wide range of temperatures suggested combined physisorption and chemisorption of NH3. Desorption tests at the same temperature as adsorption and at an elevated temperature were carried out to confirm the occurrence of chemisorption due to the interaction between NH3 and some oxygen functional groups via hydrogen bonding. The surface functional groups on the adsorbent surface were detected by Fourier transform infrared spectroscopy. The amounts of NH3 adsorbed by chemisorption were correlated with the contents of elemental oxygen present in the adsorbents. Mechanisms for chemical activation and adsorption processes are proposed based on the observed phenomena.     

Adsorption of sodium dodecylbenzenesulfonate on activated carbons: effects of solution chemistry and presence of bacteria

The objective of the present investigation was to determine the effectiveness of activated carbon in removing sodium dodecylbenzenesulfonate (SDBS) and to analyze the chemical and textural characteristics of the activated carbons that are involved in the adsorption process. Studies were also performed on the influence of operational variables (pH, ionic strength, and presence of microorganisms) and on the kinetics and interactions involved in the adsorption of this pollutant on activated carbon. The kinetics study of SDBS adsorption revealed no problems in its diffusion on any of the activated carbons studied, and Weisz-Prater coefficient (C WP) values were considerably lower than unity for all activated carbons studied. SDBS adsorption isotherms on these activated carbons showed that: (i) adsorption capacity of activated carbons was very high (260-470 mg/g) and increased with larger surface area; and (ii) dispersive interactions between SDBS and carbon surface were largely responsible for the adsorption of this pollutant. SDBS adsorption was not significantly affected by the solution pH, indicating that electrostatic adsorbent-adsorbate interactions do not play an important role in this process. The presence of electrolytes (NaCl) in the medium favors SDBS adsorption, accelerating the process and increasing adsorption capacity. Under the working conditions used, SDBS is not degraded by bacteria; however, the presence of bacteria during the process accelerates and increases SDBS adsorption on the activated carbon. Microorganism adsorption on the activated carbon surface increases its hydrophobicity, explaining the results observed.     

Cyclodextrins adsorbed onto activated carbons: preparation, characterization, and effect on the dispersibility of the particles in water

We have investigated the adsorption equilibrium of selected cyclodextrins onto activated carbons. A number of parameters were examined including the type of carbon material, the size of macrocyclic cavity, and the chemical nature of the oligosaccharide (e.g., neutral, anionic, or cationic cyclodextrin). Adsorption isotherm studies revealed that the maximum amount of cyclodextrin immobilized on the carbon surface is obtained for the native β-CD, while the adsorption capacity of the ionic cyclodextrins derivatives strongly depends on the net surface charge of the activated carbon. The affinity of cyclodextrins for activated carbons was further utilized to prepare modified activated carbons containing controlled amounts of cyclodextrins through an adsorption process. The resulting materials were characterized by N(2) adsorption-desorption volumetric measurements, FTIR and Raman spectroscopy, while the quantitative determination of the oligosaccharide content on activated carbons was performed by gravimetric measurements. On the basis of the Turbiscan results, it was found that the chemical structure of cyclodextrins, which are incorporated in the carbon framework, had significant influence on the dispersibility and stabilization of the solid particles in water. Agglomeration and precipitation of the carbon particles were markedly suppressed with substituted cyclodextrins whose hydroxyl groups were partially substituted by methyl or alkylammonium groups.