KOH活化木屑生物炭制备活性炭及其表征

以木屑热裂解的生物质炭为原料,氢氧化钾为活化剂,采用化学活化法制备活性炭,探讨了碱炭比、活化温度和活化时间对活性炭吸附亚甲基蓝吸附值的影响。 利用N2吸附实验、XRD和FTIR等实验技术,对原料与制备活性炭的结构与性能进行了表征。 结果表明,在碱炭质量比为1.5、活化温度750 ℃、活化时间2 h的条件下,所制备的活性炭对亚甲基蓝吸附值为255 mg/g,BET总比表面积为1514 m2/g,中孔比表面积为110 m2/g,吸附总孔容为0.821 cm3/g,中孔孔容为0.117 cm3/g,吸附平均孔径为2.170 nm。     

水蒸气活化制备烟杆基颗粒活性炭的研究

以烟杆废弃物为原料,以木焦油为主的复合粘结剂,通过水蒸气活化制备了烟杆基颗粒活性炭.对影响颗粒活性炭吸附性能和收率的因素如活化温度、活化时间、水蒸气流量进行了系统研究,得到了最佳工艺条件:活化温度为900℃,活化时间为60 min,水蒸气流量为3.31 g/min.该工艺条件下,烟杆基颗粒活性炭对碘的吸附值为1028 mg/g,对亚甲基蓝的吸附值为285 mg/g,收率为24.39%.同时,测定了该活性炭氮吸附,通过BET计算了活性炭的比表面积,并通过密度函数理论(DFT)表征了活性炭的孔结构.结果表明,该活性炭为微孔型,BET比表面积为1073 m2/g,总孔容为0.8152 ml/g.     

KOH活化糠醛渣制备活性炭机理与表征

以糠醛渣为原料、KOH为活化剂,采用两步活化法制备了活性炭。考察了活化温度、活化时间、碱炭比和浸渍时间对活性炭孔结构及吸附性能的影响。采用低温N2吸附、BET、BJH及DFT理论对活性炭孔结构进行了表征分析,利用傅里叶变换红外-拉曼光谱仪检测其表面官能团,分别使用扫描电镜和X射线衍射对其进行表观形貌观察和晶型分析。结果表明,制备活性炭的最佳工艺条件为:活化温度800℃、活化时间3h、碱炭比3∶1、浸渍时间12h。所制备的糠醛渣活性炭的吸附孔径分布集中,吸附孔容为0.8825cm2/g,DFT总比表面积为3290.5m2/g,其碘吸附值和亚甲基蓝吸附值分别为2107.32mg/g和39.67mL/0.1g。     

KOH活化糠醛渣制备活性炭及其表征

以糠醛渣为原料、KOH为活化剂,采用两步活化法制备了活性炭。考察了活化温度、活化时间、碱炭比和浸渍时间对活性炭孔结构及吸附性能的影响。采用低温N2吸附、BET、BJH及DFT理论对活性炭孔结构进行了表征分析,利用傅里叶变换红外-拉曼光谱仪检测其表面官能团,分别使用扫描电镜和X射线衍射对其进行表观形貌观察和晶型分析。结果表明,制备活性炭的最佳工艺条件为:活化温度800℃、活化时间3h、碱炭比3∶1、浸渍时间12h。所制备的糠醛渣活性炭的吸附孔径分布集中,吸附孔容为0.8825cm2/g,DFT总比表面积为3290.5m2/g,其碘吸附值和亚甲基蓝吸附值分别为2107.32mg/g和39.67mL/0.1g。     

枣核活性炭对罗丹明B吸附性能的研究

采用ZnCl_2活化法制备了枣核活性炭,研究了枣核活性炭对罗丹明B的吸附性能。采用低温氮气吸附脱附、FT-IR等方法对活性炭进行表征,结果显示,活性炭是中孔结构,中孔容为0.92cm~3/g,平均孔径为3.1 7nm,BET比表面积达1223.25m~2/g。研究了溶液初始浓度、吸附时间和活性炭质量浓度等因素对平衡吸附量的影响,以及罗丹明B在枣核活性炭上的吸附平衡与动力学。通过Langmuir等6种吸附等温模型对吸附数据进行拟合,结果表明,Redlich-Peterson模型能较好地描述罗丹明B在活性炭上的吸附平衡;动力学研究表明,该吸附过程符合Elovich模型。     

双电层电容器用新型无灰煤(HyperCoal)基活性炭的制备

以无灰煤(HyperCoal)为原料,KOH和CaCO3为活化剂制备了煤基活性炭,采用低温N2吸附法表征了活性炭的比表面积和孔结构,测定了活性炭用作双电层电容器(EDLC)电极材料的电化学性能。考察了炭化温度、活化温度、活化时间和活化剂对活性炭电容特性的影响。研究结果表明,比表面积和比电容随着炭化温度的升高而降低,活化温度过高或活化时间太长对比电容有不利影响。此外,CaCO3影响活化过程中孔的开发,显著降低所制备活性炭的比表面积和比电容。在炭化温度为500℃、活化温度为800℃、KOH与焦的质量比为4∶1和活化时间2 h下所得活性炭的比表面积和总孔容分别达到2 540 m2/g和1.65 cm3/g,该活性炭电极在0.5 mol/L TEABF4/PC电解液中的比电容达到最大值46.0 F/g。     

微波辐射紫茎泽兰制备优质活性炭的研究

以紫茎泽兰为原料,碳酸钾为活化剂,采用超声波浸渍,微波辐射法制备活性炭.研究了浸渍方式与时间、微波功率、微波辐射时间、剂料比对活性炭吸附性能和得率的影响.得到了本实验条件下的优化工艺条件:超声波浸渍20min、120℃脱水2h,微波功率700W、微波辐射时间12min、剂料比1.25∶1.优化工艺条件下制备的活性炭碘吸附值为1470.27mg/g,亚甲基蓝吸附值为300mL/g,得率为16.35%.浸渍时间极大的缩短,微波辐射时间只有传统法活化时间的1/15左右,活性炭的吸附指标超过了国标GB/T 13803.1-1999和GB/T 13803.2-1999一级品的标准,其中碘吸附值是国家一级标准的1.47倍,亚甲基蓝吸附值是国家一级标准的2.73倍.同时,测定了该活性炭氮吸附,其BET比表面积为1540.97m2/g,总孔容为0.7393mL/g,并通过DFT表征了活性炭的孔径分布,结果表明该活性炭为微孔型活性炭.     

高热稳定性、 高比表面积低铈型铈锆钇储氧材料的制备及其性能研究

采用氨水 碳酸铵混合沉淀剂制备了低铈型铈锆钇三组分储氧材料. 采用X射线衍射、 BET、 氧脉冲吸附和H2程序升温还原(H2-TPR)等技术对材料的晶体结构、 比表面积、 孔结构、 储氧性能和还原性能进行了研究. 结果表明， 该材料经873 K焙烧4 h后比表面积达到116.8 m2/g, 孔容达到0.30 cm3/g, 经1 273 K老化10 h后, 比表面积和孔容仍然保持在68.1 m2/g和 0.22 cm3/g. 由XRD结果可知, 材料的物相组成为四方相的Zr0.84 Ce0.16 O2, 在热处理过程中物相结构稳定. 氧脉冲吸附和程序升温还原的结果表明, 材料储氧性能保持较好.     

新型功能介孔吸附剂NiNb_2O_6的合成及其吸附性能研究

通过柠檬酸溶胶-凝胶反应,合成了新型功能介孔NiNb2O6吸附剂,通过X-射线粉末衍射仪(XRD)、透射电镜(TEM)和比表面积及孔径分析(BET)对其结构进行表征。通过影响因素实验、吸附动力学实验和等温吸附实验,探讨了NiNb2O6吸附剂对水溶液中亚甲基蓝的吸附性能和机理。结果表明,NiNb2O6介孔吸附剂具有正交相晶体结构,平均粒径为30~200nm,比表面积为66.3m2/g。吸附剂用量、温度和pH值均对吸附行为有一定的影响;在35℃时,亚甲基蓝在吸附剂上吸附行为符合Langmuir方程,吸附动力学符合拟二级动力学方程,初始浓度为40mg/L,pH值为7.03时,0.2g介孔吸附剂NiNb2O6对亚甲基蓝的吸附量最大,吸附过程中液膜扩散为主要速率控制步骤。     

关于亚甲基蓝在活性炭表面吸附投影面积σA的探讨

溶液吸附法测定活性炭比表面积是大学本科基础物理化学实验中一个较重要的实验.亚甲基蓝在活性炭表面的吸附符合Langmuir单分子层吸附,但按照实验教科书及文献介绍的溶液吸附法测定活性炭比表面积的方法,大量学生实验的测定结果比活性炭实际比表面积偏低很多.本文以BET表面吸附装置测定活性炭比表面积,再以溶液吸附法测定了亚甲基蓝在活性炭表面的最大吸附量Γ∞,计算了亚甲基蓝在活性炭表面吸附投影面积σA.结果表明亚甲基蓝在活性炭表面可能不是端基吸附,而是平面吸附,分子的投影面积σA应为1.35×10-18 m2.     

Preparation and characteristics of electrospun activated carbon materials having meso- and macropores

Mesoporous activated carbon samples were prepared from electrospun PAN-based carbon fibers using physical activation with silica. Textural characterization was performed using nitrogen adsorption at 77 K. The BET specific surface area and pore size distribution of silica activated carbon materials were investigated. According to the increment of silica, BET specific surface area was increased about thirty times and it was found that silica activated carbon materials were highly mesoporous by studying pore surface distribution and pore volume distribution. Surface morphology of silica activated carbon materials were observed by SEM images. The spherical typed carbon materials were investigated. The diameter of spherical typed carbon materials was increased in proportional of the increment of silica.     

Study of Microstructure of High-Surface-Area Polyacrylonitrile Activated Carbon Fibers

High-surface-area polyacrylonitrile (PAN) activated carbon fibers having different pore size distribution activated by KOH were investigated. Nitrogen adsorption, XRD, SEM, and TEM were used to characterize the microstructure of PAN-ACFs. The specific surface area of samples was calculated from the standard BET method, and micropore surface area and volume were obtained from the Horvath-Kawazoe equations. The average pore size and characteristic energy were calculated by the Dubinin-Radushkevich equation according to the multistage adsorption mechanism. The whole pore size distribution was calculated by employing the regularization method according to the density functional theory, which is based on a molecular model for the adsorption of nitrogen in porous solids. It was shown that the isotherms were type I, the pore size was around 0.4-0.8 nm, and the mesorpore size was around 2-4 nm. The XRD pattern showed that PAN-ACFs activated by KOH are of amorphous material composed of very small crystallites. The SEM and TEM results showed that the monograph differs with differing activation degree, and the network is uniform or disordered. That all of these methods are in good agreement with one another. Copyright 2001 Academic Press.     

Structural Characterization and Property Study on the Activated Alumina-activated Carbon Composite Material

AlCl3,NH3·H2O,HNO3 and activated carbon were used as raw materials to prepare one new type of activated alumina-activated carbon composite material.The influence of heat treatment conditions on the structure and property of this material was discussed;The microstructures of the composite material were characterized by XRD,SEM,BET techniques;and its formaldehyde adsorption characteristic was also tested.The results showed that the optimal heat treatment temperature of the activated alumina-activated carbon composite material was 450 ℃,iodine adsorption value was 441.40 mg/g,compressive strength was 44 N,specific surface area was 360.07 m2/g,average pore size was 2.91 nm,and pore volume was 0.26 m3/g.According to the BET pore size distribution diagram,the composite material has dual-pore size distribution structure,the micro-pore distributes in the range of 0.6-1.7 nm,and the meso-pore in the range of 3.0-8.0 nm.The formaldehyde adsorption effect of the activated alumina-activated carbon composite material was excellent,much better than that of the pure activated carbon or activated alumina,and its saturated adsorption capacity was 284.19 mg/g.     

The study of controlling pore size on electrospun carbon nanofibers for hydrogen adsorption

Polyacrylonitrile (PAN)-based carbon nanofibers (CNFs) were prepared by using electrospinning method and heat treatment to get the media for hydrogen adsorption storage. Potassium hydroxide and zinc chloride activations were conducted to increase specific surface area and pore volume of CNFs. To investigate the relation between pore structure and the capacity of hydrogen adsorption, textural properties of activated CNFs were studied with micropore size distribution, specific surface area, and total pore volume by using BET (Brunauer-Emmett-Teller) surface analyzer apparatus and the capacity of hydrogen adsorption was evaluated by PCT (pressure-composition-temperature) hydrogen adsorption analyzer apparatus with volumetric method. The surface morphology of activated CNFs was observed by SEM (scanning electron microscope) images to investigate the surface change through activation. Even though specific surface area and total pore volume were important factors for increasing the capacity of hydrogen adsorption, the pore volume which has pore width (0.6-0.7 nm) was a much more effective factor than specific surface area and pore volume in PAN-based electrospun activated CNFs.     

Effects of Cetylpyridinium Chloride on Phase and Rheological Behavior of the Diluted C(12)E(4)/Benzyl Alcohol/Water System

The influence of the pore size distribution of activated carbon on the adsorption of phenol from aqueous solutions was explored. Activated carbons with different porous structures were prepared by gasifying a bituminous coal char to different extents of burn-off. The results of adsorption experiments show that the phenol capacity of these carbons does not proportionally increase with their BET surface area. This reflects the heterogeneity of the carbon surface for adsorption. The pore size distributions of these carbons, determined according to the Dubinin-Stoeckli equation, were found to vary with the burn-off level. By incorporating the distribution with the Dubinin-Radushkevich equation using an inverse proportionality between the micropore size and the adsorption energy, the isotherms for the adsorption of phenol onto these carbons can be well predicted. The present study has demonstrated that the heterogeneity of carbon surface for the phenol adsorption can be attributed to the different energies required for adsorption in different-size micropores. Copyright 2000 Academic Press.     

苯基键合高比表面积活性炭的制备及其对挥发性有机化合物的吸附性能研究

以核桃壳为原料,经过碳化、KOH活化, 制备了高比表面积活性炭,通过三甲基氧基苯基硅烷对活性炭表面进行改性,制得苯基键合高比表面积活性炭吸附材料.通过氮气吸附法测定了苯基键合活性炭的比表面积及孔径分布;采用红外光谱、X射线光电子能谱、X射线粉末衍射技术对苯基键合活性炭的有机官能团、表面元素的化学环境及晶体结构进行了表征.将该吸附材料制成采样管,吸附空气中的挥发性有机物,二硫化碳解吸后使用气相色谱进行分析.考察了苯基键合活性炭对乙醇、丙酮、正己烷、乙酸乙酯、四氢呋喃、1,2-二氯乙烷和苯共7种挥发性有机化合物(VOCs)的吸附性能,饱和吸附量在129~216 mg/g之间;在0.05~ 2.50 mg/mL范围内,7种组分的峰高与浓度呈良好的线性关系,检出限在0.92~3.60 mg/m3之间.     

超临界CO2中以活性碳为模板由TEOS制备多孔SiO2

在超临界CO2中以活性碳为模板由正硅酸乙酯(TEOS)前体涂层焙烧法制备多孔SiO2材料。结构分析表明,超临界涂层法制备的多孔SiO2材料的比表面积、比孔容和平均孔径分别达到1147m2/g、1.4cm3/g和2.20nm,优于常规液相浸渍涂层法。并研究了活性碳含水量、超临界涂层的温度和压力等因素对涂层效果的影响,确定了较好的涂层条件。     

Adsorption Behaviors of CO2 and NH3 on Chemically Surface-Treated Activated Carbons

The adsorption characteristics of activated carbon treated with 30 wt% HCl and 30 wt% NaOH were investigated. The acid and base values were determined by Boehm's method and the surface structures were studied by the BET method with N2 adsorption and iodine adsorption capacity. Also the adsorption properties of the activated carbons treated with acid and base chemical solutions were investigated with CO2 and NH3 adsorptions. Different adsorption behaviors of CO2 and NH3 on the modified activated carbons were observed, even though the physical surfaces of the activated carbons (i.e., specific surface area, pore size, and pore volume) were not significantly changed. Copyright 1999 Academic Press.     

Adsorption of Dyes from Aqueous Textile By-Products on Activated Carbon from Scenedesmus obliquus

The adsorption of activated carbon prepared from Scenedesmus obliquus (algae) was evaluated through adsorption of Astrazon red. The adsorption efficiency of activated carbon was determined based on the specific surface area and pore size distribution. These results were compared with the results obtained with untreated algae. Approximately a 3-fold increase in the percentage of dye removal was observed for activated carbon compared to the untreated material. The primary reason for this observation may be the increase in specific surface area and total pore volume by chemical activation from 0.0136 to 423.7001?m²?g^?1 and from 0.0012 to 0.1643?cm³?g^?1, respectively. A pseudo-second-order model was fit with the kinetic data and the results indicate chemical adsorption. The maximum adsorption capacity of activated carbon was 181.82?mg?g^?1 at 25°C according to Langmuir isotherm model.     

生物质碳材料的孔道分析

生物质碳材料的孔道类型和孔径大小制约着材料有效的活性位点数量,影响材料的性能。孔道分类又是孔径分析的前提条件。因此,建立孔道分类的方法非常有意义。随着生物质碳材料的深入研究,研究者对其孔道分析的要求逐渐提高。他们用实际的吸脱附等温线与IUPAC规范中的吸脱附等温线进行匹配,来分类生物质碳材料的孔道。然而实际的吸脱附等温线具有不规则性,难以匹配IUPAC规范中的吸脱附等温线。所以,本文提出了孔隙率和比表面积占有率的孔道分类新方法。自制生物质碳材料,运用物理吸附仪和TEM (Transmission electron microscope)对其进行表征,采用BET方程（Brunauer-Emmett-Teller）、t-plot方法(Thickness-plot)、DFT方法（Non-local Density Functional Theory）、BJH（Barrett Joyner and Halenda）方法对其孔道进行分析。研究表明,采用孔隙率和比表面积占有率对其进孔道分类,可以准确的定义出微孔生物质碳材料、介孔生物质碳材料和微介孔生物质碳材料。本文用标准样品对孔隙率和比表面积占有率的孔道分类新方法进行论证,结果一致。因此,本文提出的孔隙率和比表面积占有率的孔道分类新方法准确可靠,实用性高。