硝酸浸渍对活性炭纤维还原NO性能的影响

经初步筛选选定以聚丙烯腈为原料加工而成的两种活性炭纤维毡 (ACF) ,研究了其本体和经硝酸浸渍处理后脱除NO的性能 ,表明ACF经硝酸处理后脱除NO的性能有所提高 .在ACF上进行的程序升温脱附试验表明 ,ACF经硝酸浸渍处理后对O₂ 、CO和NO的吸附性能均强于未处理的 ,唯有CO₂ 相反 .根据文献与实验现象 ,认为NO在碳纤维上的解离吸附是此反应的控制步骤 ,反应的初级产物为CO₂ ,并按一级反应处理 ,得到了NO与碳反应的反应速率与温度的关联式 .研究表明经硝酸浸渍处理后的ACF脱除NO的性能恒优于未处理的 .     

Activated carbon fibers as redox mediators for the increased reduction of nitroaromatics

Activated carbon fibers (ACFs) were used as redox mediators in the anaerobic chemical reduction of two model nitroaromatic compounds: 4-nitrophenol and 3-chloronitrobenzene. The effect of ACF chemical properties on the reduction of nitroaromatic compounds was measured by chemical oxidation of ACFs with 8 M nitric acid and thermal treatment at 700 °C under an inert atmosphere of hydrogen:helium (1:99%), before their use in batch experiments. The results show that ACFs are necessary to transform the nitroaromatic compounds to their corresponding aromatic amines, indicating the function of ACFs as redox mediators. Furthermore, the oxidation and thermal modification of ACFs clearly changes the redox properties of these materials, with the former being the better option to increase the concentration of quinone groups (1.68 times), and therefore the redox mediating capacity of ACFs (up to 1.38 times).     

热改性活性炭纤维对甲苯的吸附和分形分析

在氮气气氛中,N2的流量为100 mL/min,分别在450℃和950℃并均加热30 min制备了活性炭纤维的热改性样品,分别改性样品记为ACF1和ACF2。分别考察了未改性样品ACF0和改性样品ACF1及ACF2对低浓度甲苯的吸附等温线。基于甲苯吸附等温线,利用Mandelbrot分形理论对3种ACF样品进行了分形维数(Df)的分析,计算得到3种ACF样品的Df值分别为Df,0=2.542 5,Df,1=2.569 2,Df,2=2.573 4,从分形理论角度解释了热改性改善ACF吸附性能的原因。最后通过对ACF样品的表征数据验证了试验结果和ACF结构分形分析的正确性。     

Shear strength of anisotropic conductive adhesive joints under hygrothermal aging and thermal cycling

The shear strength behaviors of Anisotropic Conductive Adhesive Film (ACF) joints were investigated experimentally with various environments. The shear tests of ACF joints were performed at different constant temperature conditions. It is found that the shear behaviors of the ACF joints are strongly dependent on testing temperature, and the shear strength decrease and the maximum displacement increases with increasing temperature. The shear strength of ACF joints was also investigated under hygrothermal aging and thermal cycling. The results show that the shear strength of ACF joints gradually decreases at first, then quickly decreases and finally the rate of decrease slows down again with increasing hygrothermal aging time. However the shear strength of ACF joints after thermal cycling increases firstly and then decreases with increasing thermal cycling time.     

用恒电流法研究Fe（Ⅲ）EDTA对银的氧化过程

本文采用银旋转圆盘电极,在氟离子、溴离子、碘离子以及其他照相辅加剂存在下对Fe(Ⅲ)EDTA氧化金属银的过程进行了研究,以恒电流法做为检测手段,初步探讨了Fe(Ⅲ)EDTA络合物对金属银漂白过程机理。实验揭示了各种卤离子在Fe(Ⅲ)EDTA对银的氧化过程中的行为。pH和Fe(Ⅲ)EDTA浓度对该氧化还原反应的影响,以及某些含有巯基的化合物对Fe(Ⅲ)EDTA氧化反应的加速作用机理。     

活性碳纤维表面氧化还原机理研究

用X射线光电子能谱分析技术,研究了氧化还原反应前后ACF表面结构的变化以及反应条件与结构变化的关系。结果证明ACF的氧化还原反应机理至少包括两种反应过程,一为增加C—OH基团浓度的反应,二为增加C=O基因浓度的反应。在强烈的氧化条件下,还会发生部分基因最终被氧化成为二氧化碳的反应。当表面含氧基团浓度达一定值时,同种氧化剂进一步氧化不会明显增加含氧量,但改用更强的氧化剂时,表面含氧量会增大到另一新的平衡值。ACF表面存在一系列电极电位不同的氧化还原反应中心,在不同氧化还原体系中,ACF表面参与反应的基因种类和浓度都不一样。     

Adsorption Behavior of Dyestuffs on Hollow Activated Carbon Fiber from Biomass

This study focuses on the adsorption behavior of typical dyestuffs (methylene blue and reactive black 5) on hollow activated carbon fibers (ACFs) obtained from Kapok- and Hasuo-seed based biomass. It was found that the adsorption of dyestuffs on ACFs increased with increasing pH and temperature. In addition, the Hasuo-seed based ACFs showed higher adsorption capacities than the Kapok-seed based ACFs for dyestuffs. It was also determined from the adsorption energy distribution results that the ACFs are having energetically heterogeneous surfaces. The results clearly indicated that the prepared ACF in this study could efficiently remove dyes dissolved in water.     

Contraction stress build‐up of anisotropic conductive films (ACFs) for flip‐chip interconnection: Effect of thermal and mechanical properties of ACFs

The important mechanical mechanism for the electrical conduction of anisotropic conductive films (ACFs) is the joint clamping force after the curing and cooling processes of ACFs. In this study, the mechanism of shrinkage and contraction stress and the relationship between these mechanisms and the thermomechanical properties of ACFs were investigated in detail. Both thickness shrinkages and modulus changes of four kinds of ACFs with different thermomechanical properties were experimentally investigated with thermomechanical and dynamic mechanical analysis. Based on the incremental approach to linear elasticity, contraction stresses of ACFs developed along the thickness direction were estimated. Contraction stresses in ACFs were found to be significantly developed by the cooling process from the glass‐transition temperature to room temperature. Moreover, electrical characteristics of ACF contact during the cooling process indicate that the electrical conduction of ACF joint is robustly maintained by substantial contraction stress below T_g. The increasing rate of contraction stresses below T_g was strongly dependent on both thermal expansion coefficient (CTE) and elastic modulus (E) of ACFs. A linear relationship between the experimental increasing rate and E × CTE reveals that the build‐up behavior of contraction stress is closely correlated with the ACF material properties: thermal expansion coefficient, glassy modulus, and T_g. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2634–2641, 2004     

活性碳纤维氧化还原机理初探

在系统研究了活性碳纤维(ACF)氧化还原功能特征的基础上,进一步利用 X 射线衍射、红外、核磁及化学分析等技术,研究了 ACF 在惰性气氛中,非水介质中的氧化还原特性以及ACF 比表面积、表面官能团、水等对氧化还原性能的影响,从面对 ACF 的氧化还原反应机理提出了一些新的见解。实验结果表明,ACF 的氧化还原功能与空气(氧等)的吸附无关,主要是由于 ACF 表面的官能团所引起,其官能团不仅仅是≥C—OH,在有水存在时,≥C—H、甚至>C=O 也参与氧化还原反应,并且还是主要的反应.水对氧化还原容量影响甚大.ACF 的氧化还原容量随比表面积变化不大。     

The effects of picolinic acid and pH on the adsorption of Cu(II) by activated carbon fibers

The adsorption characteristics of Cu(II) on activated carbon fibers (ACFs) from simulated wastewater was investigated in the picolinic acid concentration range from 0.15 to 15 mM by varying pH from 2 to 8. When pH is below 4, the removal fraction of Cu(II) ions decreased with the decrease of pH. The removal fraction of Cu(II) ions is almost constant above pH 4. The removal efficiency of Cu(II) ions increased as the molar ratio of picolinic acid to Cu(II), specific surface area of ACFs and pH of the solution increased. In the case of [Pic]/[Cu(II)]=10, complete adsorption of Cu(II) was performed on ACF, even at pH 2.