H-K法研究ACFs的微结构

ＡＣＦｓ的吸附性能主要取决于比表面积和孔隙结构。在不同相对压力下的吸附行为对应不同的孔隙结构。在一定范围内微孔是决定吸附能力大小的重要因素。以Ｎ２吸附等温线为依据,采用Ｈ－Ｋ法考察了不同比表面积ＡＣＦｓ在微观结构以及吸附 的差异。     

Removal of trace Cd(II) from water with the manganese oxides/ACF composite electrode

The Manganese oxide/active carbon fiber (MO/ACF) was prepared and its electrosorptive properties of Cd(II) in aqueous solution were investigated. The structure of MO/ACF was characterized with transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Furthermore, the Cd(II) electrosorptive properties of MO/ACF electrodes with different bias potentials, ionic strengths, and loaded amount of manganese oxides were measured and the electrosorption isotherm and kinetics were investigated. The Cd(II) electrosorptive capacity of MO/ACF was 6 times higher than that of pure ACF. The optimal adsorptive bias voltage was 1.5 V and the optimal electrolyte concentration of NaCl was 0.1 mol/L. The adsorption isotherm was agreed well with the Freundlich adsorption model and its maximum electrosorption capacity was 14.88 mg/g by Langmuir model. The higher adsorptive capacity of MO/ACF than that of pure ACF is attributed to higher capacitance and more adsorptive sites of MO/ACF.     

Enhanced adsorption of metal ions onto functionalized granular activated carbons prepared from cherry stones

Some granular activated carbons (GACs) were prepared from cherry stones (CS), an agricultural waste, by thermal methods following pyrolysis in nitrogen and subsequent activation (with air, carbon dioxide and steam) or single-step activation in steam. A GAC prepared by activation with carbon dioxide was further treated with several oxidizing agents (air, air-ozone mixture, nitric acid and hydrogen peroxide). The non-oxidized GACs produced have surface areas ranged from 508 to 901m(2)/g and show a predominantly micro- and macropores structure. Oxidation treatments, especially with nitric acid and ozone, led to the fixation of high amounts of acidic surface oxygen complexes (SOCs), thus making the carbon surface more hydrophilic. Contrary to oxidation with the other agents, the ozone treatment, at the conditions applied in this work, does not decrease the GAC surface area. Both, the non-oxidized and the oxidized GACs were used as adsorbent to study the adsorption of Cu(II) from aqueous solution. Adsorption isotherms were obtained at 25 degrees C and data were well fitted to the Langmuir equation. The results show that the Cu(II) uptake of the non-oxidized GACs is not great, but similar to that of the commercial grade Filtrasorb 400. The adsorption capacity for Cu(II) could be greatly enhanced by GAC oxidation, especially with nitric acid and ozone treatments. The larger adsorption capacity of the oxidized GACs has been attributed to oxygen functionalities (mainly carboxylic) fixed on the GAC surface, which can remove Cu(II) species from water by both ion-exchange and surface complexation mechanisms. The ozonated GAC was also evaluated for the adsorption of Co(II) species from single solute and Cu(II)-Co(II) binary mixture solutions. The functionalization of GAC by the ozone treatment improved the adsorption of both Cu(II) and Co(II) regardless of the fact that they were in single solute or binary systems.     

改性PAN—ACFs对甲醛吸附性能的初步研究

聚丙烯腈（PAN-polyacrylonitrile)活性炭纤维（ACF-Activated carbon fiber)经浸渍处理后,通过低温氮气吸附法测定了其吸附等温线,并通过BET方法计算了比表面积SBET,用Dubinin-Astakhjov方程计算了微孔表面积Smic和微孔容积Vmic,用Horvath-Kawazoe方程计算了微孔容积Vmic和平均孔径D,发现处理后样品的比表面积、微孔容积均小于未经处理的原样,而其对甲醛的静态与动态吸附容量都大于未经过处理的原样品,比表面积太小的样品均小于未经处理的原样,而其对甲醛的静态与动态吸附容量都大于未经过处理的原样品,比表面积太小的样品对甲醛的吸附容量小于较高比表面积的样品的吸附容量,部分被吸附物于150℃不能够完全脱除,经推知,所发生的吸附既有物理吸附又有化学吸附,是其表面官能团与孔结构共同作用的结果,样品的无素分析结果表明,处理后样品的C、N含量均增加,O含量降低,吸附过程中含N官能团的作用较显著,浸渍后的样品经热处理,其吸附容量高于未经热处理的样品,说明热处理可以脱除样品表面的杂原而在PAN-ACFs表面留下许多活性位。     

非苯乙烯型超高交联树脂的修饰及对酚类化合物的吸附

分别通过4,4'-二氯甲基联苯与1,4'-二氟甲基苯的傅克烷基化聚合和胺化反应,制得一类比表面积可达1138 m2/g的胺基吸附树脂新材料.研究表明,这类非苯乙烯型胺基树脂对苯酚、对硝基苯酚的饱和吸附容量分别可达140 mg/g和331 mg/g,明显优于国内外用于酚类吸附的AmberliteXAD-4、H103等吸附...     

高温热处理对活性炭纤维微孔及表面性能的影响

研究了1173K高温改性处理对沥青基活性炭纤维吸附性能、孔径分布、微孔结构和表面化学的影响。低温(77K)N2吸附结果表明热处理后活性炭纤维比表面积略有下降，通过密度函数理论解析活性炭纤维全孔范围的孔分布得出活性炭纤维表面孔径大于1．0nm的微孔明显减少，微孔孔径更加集中于0．5nm～1．0nm，从而提高了活性炭纤维的碘吸附值。X射线衍射分析表明活性炭纤维是乱层石墨结构，热处理使活性炭纤维类石墨微晶碳层面的层间距下降，X光电子能谱分析表明热处理后活性炭纤维表面的含氧官能团C=O和COOH的含量变化不大，而呈碱性酚羟基C—OH含量的明显下降使活性炭纤维表面碱性降低。     

Simulataneous pentachlorophenol decomposition and granular activated carbon regeneration assisted by dielectric barrier discharge plasma

An integrated granular activated carbon (GAC) adsorption/dielectric barrier discharge (DBD) process was applied to the treatment of high concentration pentachlorophenol (PCP) wastewater. The PCP in water firstly was adsorbed onto GAC, and then the degradation of PCP and regeneration of exhausted GAC were simultaneously carried out by DBD. The degradation mechanisms and products of PCP loaded on GAC were analyzed by EDX, FT-IR and GC–MS. The results suggested that the CCl bonds in PCP adsorbed by GAC were cleaved by DBD plasma, and some dechlorination and dehydroxylation products were identified. The adsorption capacity of adsorption/DBD treated GAC could maintain relatively high level, which confirmed that DBD treatment regenerated the GAC for subsequent reuse. The adsorption of N₂, Boehm titration and XPS were used to investigate detailed surface characterizations of GAC. It could be found that DBD plasma not only increased the BET surface area and pore volume in micropore regions, but also had remarkably impact on the distribution of the oxygen-containing functional groups of GAC.     

Surface modification of coconut shell based activated carbon for the improvement of hydrophobic VOC removal

In this study, coconut shell based carbons were chemically treated by ammonia, sodium hydroxide, nitric acid, sulphuric acid, and phosphoric acid to determine suitable modification for improving adsorption ability of hydrophobic volatile organic compounds (VOCs) on granular activated carbons (GAC). The saturated adsorption capacities of o-xylene, a hydrophobic volatile organic compound, were measured and adsorption effects of the original and modified activated carbons were compared. Results showed that GAC modified by alkalis had better o-xylene adsorption capacity. Uptake amount was enhanced by 26.5% and reduced by 21.6% after modification by NH₃H₂O and H₂SO₄, respectively. Compared with the original, GAC modified by acid had less adsorption capacity. Both SEM/EDAX and BET were used to identify the structural characteristics of the tested GAC, while IR spectroscopy and Boehm's titration were applied to analysis the surface functional groups. Relationships between physicochemical characteristics of GAC and their adsorption performances demonstrated that o-xylene adsorption capacity was related to surface area, pore volume, and functional groups of the GAC surface. Removing surface oxygen groups, which constitute the source of surface acidity, and reducing hydrophilic carbon surface favors adsorption capacity of hydrophobic VOCs on carbons. The performances of modified GACs were also investigated in the purification of gases containing complex components (o-xylene and steam) in the stream.     

活性炭纤维吸附氙气机理的研究

研究了不同基体的活性炭纤维对氙气的吸附性能,同时对活性炭纤维结构修饰后的性能进行研究.结果表明活性炭纤维对氙气的吸附量不是随表面积增大而增加,修饰后的活性炭纤维的微孔尺寸变窄,对氙气的吸附量有所增加,吸附前后活性炭纤维的结构未发生变化.     

Reduction–adsorption behavior of platinum ions on activated carbon fibers

A number of activated carbon fibers (ACF) were prepared by activation with steam, Phosphoric acid, or Zinc Chloride. Their reduction-adsorption behavior for Pt(IV) was studied using scanning electron microscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy. The results show that Pt ions in solution can be adsorbed by ACFs and reduced to metallic platinum. The reduction–adsorption capacity of ACF for Pt could be greater than 200 mg/g. Generally, higher specific surface area or lower electrode potential produces a higher capacity. Most of the adsorbed platinum ions were reduced into metallic platinum, and about 25% of platinum atoms remained as Pt(II) or Pt(IV). XRD examination showed that the Pt particles on the ACF surface were crystallized when heated to 673 K.     

活性炭对扑热息痛的吸附行为和体外释放性能

主要研究了药用颗粒活性炭对扑热息痛的吸附行为和体外释放性能。采用N2吸附表征了三种活性炭的孔结构，借助Beohm滴定法和质量滴定法测定了活性炭的表面含氧官能团和零电荷点pHPZC；考察了比表面积、孔隙结构与吸附性能和体外释放性能的关系，及活性炭表面化学性质对吸附性能的影响。结果表明：活性炭的孔结构和表面化学性质对吸附性能和体外释放性能具有决定性的影响。比表面积高、孔隙发达、孔径分布集中在2nm-11m,之间的中孔型活性炭，对扑热息痛的吸附力很强，平衡吸附量达到了358mg／g，累计释放率为7％；具有广谱孔径分布的活性炭，平衡吸附量为281mg／g，可以缓释12h以上，累计释放率达到27％。活性炭表面的酸性含氧官能团对吸附扑热息痛具有一定的促进作用。三种活性炭的释药过程均符合Higuchi方程释药模式。     

利用铈盐改性修饰活性炭纤维结构

利用硝酸铈铵对活性炭纤维进行了化学改性。研究了铈盐改性前后活性炭纤维的微观结构和表面化学结构的变化。结果表明，活性炭纤维经铈盐处理后，比表面积降低10％～20％左右，微孔孔径分布没有发生明显的变化，表面氧含量从原子分数11％提高至25％，使活性炭纤维表面形成更多的高价态含氧基团。并通过X射线光电子能谱和热重-红外联用的分析结果相结合，较为详细地、定量地分析了活性炭纤维表面的含氧基团。结果表明，利用热重一红外联用技术对活性炭纤维表面含氧基团的种类及其相对量分析结果与基于X射线光电子能谱的C1s分峰结果定量分析基本一致，两种结果可互为验证。     

氟化活性炭纤维的制备及其憎水性

将活性炭纤维（ACF）和氟气反应制备了氟化活性炭纤维（FACF）。XPS的研究结果表明FACF的碳原子是以sp^3杂化轨道同氟原子形成共价键。αs图分析氮吸附等温线的结果表明，ACF氟化后其比表面积和微孔容积显著降低、微孔宽度基本不变。FACF对水的吸附量极小，微孔表面具有完美的憎水性和高稳定性。     

Effects of adsorptive properties of biofilter packing materials on toluene removal

Various adsorptive materials, including granular activated carbon (GAC) and ground tire rubber (GTR), were mixed with compost in biofilters used for treating gaseous toluene, and the effects of the mixtures on the stability of biofilter performance were investigated. A transient loading test demonstrated that a sudden increase in inlet toluene loading was effectively attenuated in the compost/GAC biofilter, which was the most significant advantage of adding adsorptive materials to the biofilter packing media. Under steady conditions with inlet toluene loading rates of 18.8 and 37.5 g/m³/h, both the compost and the compost/GAC biofilters achieved overall toluene removal efficiencies greater than 99%. In the compost/GAC mixture, however, biodegradation activity declined as the GAC mass fraction increased. Because of the low water-holding capacity of GTR, the compost/ground tire mixture did not show a significant improvement in toluene removal efficiency throughout the entire operational period. Furthermore, nitrogen limitations affected system performance in all the biofilters, but an external nitrogen supply resulted in the recovery of the toluene removal efficiency only in the compost biofilter during the test periods. Consequently, the introduction of excessive adsorptive materials was unfavorable for long-term performance, suggesting that the mass ratio of the adsorptive materials in such mixtures should be carefully selected to achieve high and steady biofilter performance.     

Consequence of chitosan treating on the adsorption of humic acid by granular activated carbon

In this work, equilibrium and kinetic adsorption of humic acid (HA) onto chitosan treated granular activated carbon (MGAC) has been investigated and compared to the granular activated carbon (GAC). The adsorption equilibrium data showed that adsorption behaviour of HA could be described reasonably well by Langmuir adsorption isotherm for GAC and Freundlich adsorption isotherm for MGAC. It was shown that pre-adsorption of chitosan onto the surface of GAC improved the adsorption capacity of HA changing the predominant adsorption mechanism. Monolayer capacities for the adsorption of HA onto GAC and MGAC were calculated 55.8 mg/g and 71.4 mg/g, respectively. Kinetic studies showed that film diffusion and intra-particle diffusion were simultaneously operating during the adsorption process for MGAC.     

Structure and antibacterial activity of silver-supporting activated carbon fibers

In this paper, several kinds of silver supporting activated carbon fibers (ACF-Ag) were prepared by the reduction adsorption on activated carbon fiber (ACF) activated with steam or H₃PO₄ using sisal, viscose and pitch fiber as precursors. Their pore structure and surface chemistry were characterized using nitrogen adsorption, XPS, WXRD and ICP quantitative analysis. Their antibacterial activities were tested. The results showed that metallic silver particle in micron or nano-scale size could be easily and dispersedly supported onto the surface of ACF using reduction property of ACF without largely decreasing their specific surface area. The ACF-Ag showed strong antibacterial activity against Escherichia coli and Staphylococcus aureus. The antibacterial activity has closed relationship with the precursors, the method of activation, silver content and the specific surface area of the ACFs. Generally, higher silver content and higher specific surface area provide the materials stronger antibacterial activity. ACF activated with phosphoric acid, due to the presence of certain amount of organic phosphoric groups on the surface, showed stronger antibacterial activity than those activated with steam. The antibacterial materials can be easily regenerated without decreasing their antibacterial activity and without releasing large amount of silver from the solid phase.     

炭纤维生物膜的形成机制——I、炭纤维表面特性对微生物固着化的影响

采用对比方法，借助化学分析、表面形态分析及生物相容性表征技术等系统地研究了以活性炭纤维、表面改性活性炭纤维作为细胞固着化载体的表面特性及对微物固着的影响。重点考察了纤维表面官能团、比表面积、润湿性等表面特性对微生物固着化的影响。研究结果表明：（1）炭纤维表面的吸附特性对微生物的初期固着起着重要的作用，具有高比表面积的活性炭纤维更易于微生物固着并挂膜。（2）炭纤维表面润湿性与某些酸性官能团的适量增加，有益于载体表面微生物的固着。（3）炭纤维尤其是活性炭纤维较市售有机高分子材料具有更加优异的生物相容性，前者的微生物固着化速率是后者的4倍－16倍。     

沥青基活性炭纤维的制备及其对NO的催化氧化

以沥青基炭纤维为原料,用水蒸气活化的方法制备了三种不同比表面积的活性炭纤维,并采用氮吸附法和拉曼光谱对活性炭纤维进行了表征。本文研究了活性炭纤维在常温下对模拟空气中50 ppm NO的催化氧化性能,结果表明,活性炭纤维可将NO部分催化转化为NO2,较低比表面积的活性炭纤维因为其较窄的孔径分布和较大的类石墨微晶有利于对NO的催化氧化。     

Breakthrough of methyethylketone and benzene vapors in activated carbon fiber beds

The breakthrough of low concentration methyethylketone (MEK) and benzene vapors in beds packed with rayon-based activated carbon fiber (ACF) with different surface areas was investigated. The breakthrough characteristics depend on the properties of the ACF and the vapors, as well as on the adsorption conditions. The results of dynamic adsorption in an ACF bed were consistent with those of equilibrium adsorption by gravimetric methods. The breakthrough adsorption indicates that ACF, with an appropriate surface area, could be utilized in controlling volatile organic compounds (VOCs) in indoor air.     

Adsorptive and structural characteristics of carbon sorbents

This paper describes the adsorptive, structural, and textural characteristics of carbon sorbents of various origins: OU-A activated charcoal powder (unmodified and modified with a cellulose polyelectrolyte), AUT-MI fibrous activated carbon, and expanded graphite intercalated with sulfuric acid. In accordance with their pore structure parameters and specific surface area, the highest adsorption capacity for water-soluble markers (iodine and methylene blue) and anionic surfactants is offered by the activated charcoal and fibrous carbon. Surface modification with an anionic polymer increases the adsorption of positively charged methylene blue molecules.