Influence of activated carbon oxidation treatments on the selective removalof copper and lead

Air, acid, and electrochemical oxidation treatments have been employed to carefully control the amount and distribution of acidic surface groups in a series of activated carbons prepared from apricot stones. The surface reactivity and functional group distribution of oxidized active carbons have been assessed using numerous analytical and surface measurement techniques including nitrogen sorption, elemental analysis, potentiometric titrations, zeta potential measurements, and Boehm's titrations. Preliminary electrochemical oxidation results suggest that this treatment provides better control of the resultant surface acidity of the prepared carbons. Lead and copper sorption studies indicate that it is possible to alter the selectivity of the oxidized active carbons towards heavy metals by changing the quantity and/or relative proportion of the individual oxygenated surface functional groups.     

OXIDATION OF SULFUR DIOXIDE ON WATER-REPELLENT ACTIVATED CARBON

To reduce resistances of interphase and intraparticle mass transfer in an aqueous solution, water-repellent catalysts were prepared by spraying polytetrafluoroethylene (abbreviated as PTFE) on activated carbon.

Oxidation of sulfur dioxide on activated carbon in the presence of water was chosen to elucidate the effect of water-repellent catalysts on the performances of gas-liquid cocurrent upflow and downflow reactors. The reaction rate increases and reaches a maximum with the increase in PTFE loading. The enhancement of reaction rate by PTFE may be explained by the decrease of partial wetting on the surface     

THE INFLUENCE OF OXIDATION OF THE FIBERS ON THE TRIBOLOGICAL PROPERTIES OF CARBON FIBER-REINFORCED NYLON COMPOSITES

Three-dimensional braided carbon fiber-reinforced nylon composites (C_3D/MCN) were prepared in order to investigate the influence of oxidation of carbon fibers on the tribological properties of the C_3D/MCN composites. Friction and wear tests of the C_3D/MCN composites with untreated and treated carbon fabric were conducted. The characteristics of the carbon fiber, the interface strength, the hardness, and the worn surface morphologies of the C_3D/MCN composites were analyzed. The results show that the specific surface area of treated carbon fiber was far higher than that of untreated carbon fiber and there formed a functional group of –C=O on the carbon fiber surface after air oxidation. The oxidation of the carbon fibers improved the interface strength between the carbon fibers and the matrix and had little effect on the hardness of the composites. The friction coefficient and wear rate of C_3D/MCN composites with oxidized carbon fibers were apparently lower than those with untreated carbon fibers. In conclusion, the oxidation of the fibers showed good effects on the improvement of the interface strength and the tribological properties of the composites.     

THE INFLUENCE OF OXIDATION OF THE FIBERS ON THE TRIBOLOGICAL PROPERTIES OF CARBON FIBER-REINFORCED NYLON COMPOSITES

Three-dimensional braided carbon fiber-reinforced nylon composites (C_3D/MCN) were prepared in order to investigate the influence of oxidation of carbon fibers on the tribological properties of the C_3D/MCN composites. Friction and wear tests of the C_3D/MCN composites with untreated and treated carbon fabric were conducted. The characteristics of the carbon fiber, the interface strength, the hardness, and the worn surface morphologies of the C_3D/MCN composites were analyzed. The results show that the specific surface area of treated carbon fiber was far higher than that of untreated carbon fiber and there formed a functional group of -C=O on the carbon fiber surface after air oxidation. The oxidation of the carbon fibers improved the interface strength between the carbon fibers and the matrix and had little effect on the hardness of the composites. The friction coefficient and wear rate of C_3D/MCN composites with oxidized carbon fibers were apparently lower than those with untreated carbon fibers. In conclusion, the oxidation of the fibers showed good effects on the improvement of the interface strength and the tribological properties of the composites.     

制备方法对活性炭孔结构的影响

对不同制备方法包括物理活化法、化学活化法和催化物理活化法对活性炭孔结构的影响进行了评述；讨论了在物理活化、化学活化和催化物理活化过程中孔的形成机理，以及现阶段活性炭生产中存在的问题和难点。     

氧化作用对B4C／C复合材料结构和性能的影响

考察了Ｂ４Ｃ／Ｃ复合材料在８００℃、２Ｌ／ｍｉｎ干燥空气注量的氧化环境下其性能参数如重量,体积,密度,电阻率、抗压强度的变化情况。并从材料表层结构的变化解释了这些参数的变化规律。     

THE INFLUENCE OF OXYGEN ON THE ADSORPTION OF METAL CYANIDES ON ACTIVATED CARBON

Activated carbon adsorbs insignificant quantities of oxygen from aerated water. This consumption is increased drastically during the adsorption of anionic metal cyanides. The equilibrium loadings of gold and silver cyanides increased with an increase in the level of dissolved oxygen. However, for both gold and silver cyanides an oxygen concentration occurred above which the metal loading showed no further increase. FTIR scans were used to confirm the presence of AuCN and Au( CN)₂ on the loaded carbons. It was suggested that gold and silver cyanides adsorb in two ways: ( 1) where oxygen is consumed for the oxidation of the active sites, and ( 2) where adsorption takes place without the use of oxygen. A multicomponent Freundlich-type isotherm proved to be adequate in predicting the equilibrium metal loadings for the competitive adsorption of gold and silver cyanides on activated carbon. The level of dissolved oxygen did not affect the competition between these two solutes significantly.     

活性炭纤维氧化处理前后微观结构的变化研究

将一种活性炭纤维经过3种形式的氧化处理用X射线衍射仪和氮气吸附,研究活性炭纤维氧化处理前后微观结构的变化。研究结果表明:活性炭纤维氧化处理后d002、La、Lc减小,孔隙结构发生了较大改变。     

活性硫化镍除铜(Ⅱ)的机理研究

本文研究了活性硫化镍的性质，分析了镍电解阳极液的组成，对活性硫化镍的除铜[Cu（Ⅱ）]过程进行了动力学实验并对中间产物进行了分析，提出了活性硫化镍的除铜机理：活性硫化镍有较大的比表面积，CuCl2-4不在活性硫化镍表面上作用较快，形成的Ni2+进入了溶液，由CuS于有强的吸附性，在整个除铜过程中CuS的脱附和扩散成为控制步骤．由于活性硫化镍孔结构的存在，这种除铜的扩散控制步骤可能由三维扩散控制经一中间过渡态转为一维扩散控制     

微波加热对活性炭表面性质的影响

采用了微波加热技术，在不同功率和加热时间下对BN-09颗粒炭进行改性，研究了改性前后活性炭的表面基团变化。结果表明，经微波加热处理后，活性炭表面酸性基团分解，同时碱性特征增强。微波功率越大，加热时间越长，氧含量减少越多，活性炭的碱性特征也越强。     

浸渍活性炭脱硫过程中孔结构及气体湿度的影响

<正>引言 浸渍活性炭是一种低温、高效脱硫剂,其硫容量可达52%以上,特别适合于低H_2S浓度的天然气脱硫净化过程。活性炭孔结构是影响脱硫效率的关键因素,许多人曾对此作过研究,但结果却很不一致,如Swinarski和Siedlewski的研究表明脱硫活性与孔径在3.5nm—8nm的孔表面积成正比,而认为小于3.5nm的孔没有脱硫效果,并且反应生成的硫最初总是覆盖在8nm—30nm的大孔中,这种硫不影响催化活性。Sreeramamurthy和Menon分析了活性炭孔内生成的硫,其结果表明反应最初阶段生成的硫沉积在相当于20个硫原子的大孔内,这部分约占总的硫生成量的70%,而后才填充到直至4个硫原子的微孔中,Steijins和Mars研究了不同孔结构物质的脱硫效果,发现孔径在0.5nm—1nm范围内的微孔具有最高的催化活性,太大和太小的孔的脱硫效果则要弱得多。     

载银活性炭催化氧化焦化废水的应用研究

通过对不同金属负载在活性炭 ( AC)上的催化性能研究 ,确定银负载在活性炭上后具有突出的催化性能 .在焦化废水的处理中 ,用载银活性炭作催化剂 ,30 %的 H2 O2 作氧化剂 ,室温下进行回归正交实验 ,得出了实验回归方程 ,并找出了最佳的实验条件 ,即每 1 0 0 m L焦化废水需用Ag- AC1 .5 g,H2 O2 3 m L,p H=3,CODcr值去除率在 85 %以上 .     

炭化温度对兰炭基成型活性炭性能的影响

兰炭末加入黏结剂混合成型,经炭化和活化制得成型活性炭.利用TG-DTG对热解过程中成型料的炭化行为进行探讨;测试不同炭化温度的成型活性炭的收率、抗压强度和碘吸附值,采用N2吸附法和红外光谱对450℃炭化成型活性炭的孔结构及表面化学性质进行表征.结果表明,炭化温度越高,成型活性炭的收率越小,抗压强度越小,碘吸附值越大.经450℃炭化、800℃水蒸气活化60 min制得的活性炭表面具有大量的羟基、羰基和烃羟基等活性基团,比表面积为384.53 m2/g,属于中孔隙发达的活性炭.     

活化工艺对活性炭纤维性能的影响

探讨了粘胶纤维前处理和活化条件（如活化温度、活化时间、活化剂浓度）对活化收率、ＡＣＦ比表面积、苯酚吸附量的影响。结果表明，活化收率随活化温度、活化时间和活化剂水的浓度的增加而降低，ＡＣＦ比表面积和苯酚吸附量则随之而增大，经过磷酸和氯化锌前处理，可以明显提高粘胶纤维活化收率，增加ＡＣＦ比表面积和苯酚吸附量。     

成型工艺条件对活性炭甲烷吸附性能的影响

以ＫＯＨ活化的粉状高比表面积活性炭为原料,羰酸甲基纤维素为粘结剂,制得了一系列高比表面积成型活性性炭,考察了成型压力、粘结剂添加比例及热处理等重要成型工艺条件对型炭甲烷吸附性能的影响。     

炭化对活性炭孔结构及甲烷吸附性能的影响

在惰性气氛下对以石油焦为原料 ,以 KOH为活化剂制得的超级活性炭进行了二次炭化处理 ,并考察了处理前后超级活性炭的孔结构变化及不同压力下该活性炭对甲烷的吸附行为 .结果发现 :活性炭经 1 2 0 0℃下二次炭化处理后其 BET比表面积及孔容有所下降 ,孔径分布变窄 ;其对甲烷的质量吸附量下降 ,对甲烷的体积吸附量在较低压力下 ( <3MPa)稍有增加 ,而在较高压力下 ( >3MPa)时明显减少     

预氧化处理对大同烟煤压块活性炭性能的影响

选用大同烟煤和高温煤沥青为原料 ,采用压块成型法制造煤质颗粒活性炭 .当制备过程的其他工艺条件相同时 ,氧化预处理可使最终活性炭制品的水容量、碘吸附值、亚甲蓝吸附值和四氯化碳吸附率分别提高 2 7%～ 34% ,1 34mg/g,86mg/g～ 96mg/g和 9%～ 1 3.5 % (绝对算术差值 ) ;当控制最终制品的性能为水容量 1 0 6%～ 1 1 9% ,碘吸附值 >1 0 5 0 mg/g,亚甲蓝吸附值 >2 2 5mg/g,四氯化碳吸附率 67%～ 75 %时 ,氧化预处理可使活化工序的产品得率提高 1 0 %以上 .不论对制品的吸附性能还是对产品的收率 ,氧化预处理都是绝对有利的 .     

处理方法对碳纳米管织构性质及负载Pd-Pt催化剂萘加氢反应活性的影响

采用酸性KMnO4溶液、浓HNO3／H2SO4混酸、中性H202溶液和高温熔融KOH分别对碳纳米管（CNTs）进行了氧化处理，用氮气物理吸附、高分辨透射电镜（HRTEM）、傅立叶变换红外光谱（FTIR）、化学滴定和X射线衍射（XRD）对处理后CNTs的表面性质和体相结构进行了研究，考察了其处理前后的变化及其负载的Pd—Pt催化剂在萘加氢为四氢萘反应过程中的的活性。结果表明：KMnO4和混酸处理后，CNTs表面上形成了大量含氧基团，H2O2处理时含氧基团量生成量则较少，而KOH处理后生成的含氧基团量很少，但CNTs比表面积显著提高，同时也使其体相结构破坏。CNTs负载的Pd-Pt催化剂上萘加氢反应的活性随表面羧基类基团含量的升高而增加。     

电化学再生活性炭的工艺参数研究

对所选定的活性炭,吸附苯酚饱和后者电化学再生。在室温条件下,选择４因素、２水平的正交试验方法进行了相关试验。结果表明,再生位置是活性炭再生工艺中最重要的影响因素,电解质ＮａＣｌ浓度是较重要的影响因素,再生电流和再生时间对活性炭的电化学再生有一定的影响。     

活性炭对Cs,S的吸附性能研究

借助多种现代方法对几类活性炭材料的吸附性能进行了比较分析,并以其对Cs、S的吸附实验为基础,研究了影响活性步吸附性能的几个因素：吸附材料物性、温度、吸附质、循环次数等。并对其吸附理论进行了初步探讨,认为微孔填充机理能较好地解释活性炭的吸附特性。