微波加热烟杆制备微孔活性炭的研究

研究了微波加热烟杆氯化锌活化法制备微孔活性炭的新工艺.采用正交试验研究了氯化锌浓度、浸渍时间、微波功率和活化时间对活性炭得率和吸附性能的影响.最佳工艺条件为ZnCl2浓度25%,浸渍时间36h,微波功率为700W,加热时间为16 min时,所制备的活性炭的碘吸附值为1059.32 mg/g,亚甲基蓝吸附值为21 mL/0.1g,得率为32.90 %.该工艺将常规加热方法的预热、干燥、炭化和活化简化为一个过程,所需要加热时间仅为传统方法的1/13,产品活性炭的亚甲基蓝吸附值为国家一级品标准的2.33倍.同时测定了该活性炭的氮吸附等温线,通过BET法计算了活性炭的比表面积,并通过H-K方程、D-A方程和密度函数理论(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1214m2/g,总孔容为0.7387 mL/g,微孔占总孔容74.03%,中孔占24.54%,大孔占1.43%.     

兰炭基均匀超微孔活性炭的制备及其表征

以KNO_3为氧化剂,经5%~15%(质量分数)KOH常温浸渍,在N_2-水蒸气混合气氛下进行控制热分解制备均匀超微孔活性炭。试验选用正交试验法,选择活化温度、活化时间、KOH浸渍浓度、浸渍时间等参数为影响因素,以碘吸附值为考察指标,得到最佳水平组合,活化温度900℃,活化时间1h,KOH浓度15%,浸渍时间24h。对活性炭表征结果如下:最佳样品碘吸附值达840 mg/g。BET比表面积为725cm~2/g,中值孔径为0.489nm,其中微孔容积占总孔容的70.8%,氢气最大吸附量达76.85cm3/g。该样品以超微孔为主,超微孔孔径主要分布在0.45~0.52nm之间,孔分布比较集中,可用于混合气体分离。     

K_2CO_3活化法制备芋叶柄基活性炭的研究

以废弃的芋叶柄为原料,K2CO3为活化剂,制备芋叶柄基活性炭,考察炭化和活化工艺条件对活性炭吸附性能的影响,采用等温氮吸脱附测试、扫描电子显微镜(SEM)对样品材料进行了测试。结果表明:若以碘吸附值作为评价指标,最佳工艺条件为K2CO3浓度200g/L、活化温度850℃、活化时间35min,碘值为1930.4mg/g,BET比表面积为633.215m2/g,孔容为0.194cm3/g,孔径为18.45nm。以亚甲基蓝吸附值作为评价指标,最佳工艺条件为K2CO3浓度175g/L、活化温度875℃、活化时间35min,亚甲基蓝吸附值为298.8mg/g,BET比表面积为604.708m2/g,孔容为0.076cm3/g,孔径为18.533nm。     

超高比表面积活性炭的制备与表征

以无患子残渣为原料,KOH与K2CO3作为活化剂,采用微波炭化和活化两步法制备超高比表面积活性炭,通过正交实验优化活性炭的制备工艺,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吸脱附实验、XRD、FT-IR等实验技术,对制备的活性炭结构与性能进行了表征。结果表明,在碱炭质量比为4∶1、活化温度800℃、活化时间30 min的条件下,所制备的活性炭对亚甲基蓝吸附值为595 mg/g,BET比表面积为3 479 m2/g,吸附累积总孔容达1.8262 cm3/g,平均孔径为2.0997 nm。     

椰壳纤维基高比表面积中孔活性炭的制备

以椰壳纤维为原料,制备高比表面积中孔活性炭.采用正交试验设计实验方案,研究KOH和NaOH复合活化法制备活性炭的实验方案与工艺条件.考察了活化剂配比、炭化温度、活化温度、时间和升温速率对所制活性炭吸附性能的影响.在最佳工艺条件下,所制活性炭的比表面积达到2032m2/g,中孔发达,特别是2nm～4nm的,中孔比例达到28%.活性炭对的碘吸附值为1435mg/g,亚甲基蓝吸附值为495mg/g,产率为49%.     

马尾藻基高比表面积活性炭的制备及表征

以马尾藻为原料,采用KOH活化法制备高比表面积活性炭。探索制备马尾藻基活性炭的实验方案和最佳工艺条件。采用正交实验法研究了炭化温度、炭化时间、低温活化温度、低温活化时间和浸渍时间对制得活性炭比表面积和孔容的影响。采用N_2吸附、SEM表征考察了活性炭的孔隙结构和表面形貌。通过正交实验法分析发现,制备马尾藻基高比表面积活性炭的最佳工艺条件为:炭化温度600℃,炭化时间180min,低温活化温度400℃,低温活化时间45min,浸渍时间2h。在16组实验条件下,制备的活性炭比表面积最大为3 122m2/g,所有样品的孔径几乎全部分布在6nm以内。     

兰炭基中孔活性炭的制备及性能表征

以兰炭粉为原料,水蒸汽为活化剂,采用物理活化法制备中孔活性炭。分别讨论了活化温度、活化时间、水蒸汽质量流量对活性炭碘吸附值的影响,并采用正交实验对工艺条件进行了优化。利用全自动物理吸附仪对活性炭的比表面积和孔结构进行表征。结果表明:随着活化温度的升高、活化时间的延长和水蒸汽流量的增大,活性炭的碘吸附值均呈现先升高后下降的变化规律。正交实验结果表明,水蒸汽活化兰炭粉的适宜条件为:活化温度900℃,活化时间60min,水蒸汽流量1.25g/min。此条件下制得的活性炭具有多级孔的特征,而且以中孔为主,其碘吸附值为924.45mg/g,比表面积为818.52m2/g。     

NaOH活化法制备高比表面积稻壳活性炭

以农业废弃物稻壳为原料,NaOH为活化剂,制备了中孔发达的高比表面活性炭,研究了碱炭比、活化温度对样品碘吸附值和亚甲基蓝吸附值的影响;采用SEM、TEM表征了活性炭的形貌,通过BET法计算了活性炭的比表面积,BJH方程计算出活性炭的孔径分布.结果表明,在碱炭比为3∶1、活化温度为750℃的工艺条件下制备的稻壳活性炭同时具有较高的碘吸附值和亚甲基蓝吸附值;稻壳活性炭比表面积高达2164m2/g,中孔含量达到63.67%,总孔容达到1.544mL/g.     

ZnCl_2活化红枣核制备多微孔活性炭及表征

以红枣核为原料,采用ZnCl2活化法,研究了活化温度、活化时间以及浸渍比等工艺参数对活性炭结构性能与表面化学性能的影响。采用低温N2吸附-脱附以及元素分析对活性炭结构进行表征,采用Boehm滴定、pHZPG、FT-IR等手段对活性炭表面性能进行表征。研究结果表明,当浸渍比为0.8,活化温度为700℃,活化时间为60 min时,活性炭的微孔结构较发达,活性炭BET比表面积为1 031 m2/g,总孔体积为0.504 cm3/g,平均孔径为1.95 nm,零电荷点(p HZPG)为7.01,活性炭的收率为41.6%。     

超级电容器用马尾藻基超级活性炭的制备及其电化学性能

以马尾藻为原料,采用KOH活化法制备用于超级电容器的生物质基超级活性炭。制备的超级活性炭不仅比表面积巨大,孔隙结构丰富,而且以海藻作为前驱体原料明显降低了活性炭的生产成本。采用单因素实验法分析了浸渍比、活化温度和活化时间对马尾藻基活性炭孔隙结构(比表面积、孔容及孔径分布等)的影响,探索了制备马尾藻基超级活性炭的最佳工艺条件,并研究了所制活性炭用于制备超级电容器时的电化学性能。采用N2吸附-解吸附、SEM、XRD,恒电流充放电以及循环伏安法等表征手段考察超级活性炭样品的比表面积,孔结构以及电化学性能。实验结果表明,制备马尾藻基超级活性炭的最佳工艺条件为:浸渍比4∶1,活化时间120min,活化温度800℃。在该实验条件下制得的活性炭比表面积高达2926m2/g,孔容高达1.536cm3/g,且所有活性炭的孔径大小几乎全部分布在4nm以内,孔径分布均匀。制备的超级电容器以6mol/L的KOH为电解液时,其比电容高达358.5F/g,表现出良好的电化学性能。     

Preparation of oil palm empty fruit bunch-based activated carbon for removal of 2,4,6-trichlorophenol: optimization using response surface methodology

The effects of three preparation variables: CO(2) activation temperature, CO(2) activation time and KOH:char impregnation ratio (IR) on the 2,4,6-trichlorophenol (2,4,6-TCP) uptake and carbon yield of the activated carbon prepared from oil palm empty fruit bunch (EFB) were investigated. Based on the central composite design, two quadratic models were developed to correlate the three preparation variables to the two responses. The activated carbon preparation conditions were optimized using response surface methodology by maximizing both the 2,4,6-TCP uptake and activated carbon yield within the ranges studied. The optimum conditions for preparing activated carbon from EFB for adsorption of 2,4,6-TCP were found as follows: CO(2) activation temperature of 814 degrees C, CO(2) activation time of 1.9h and IR of 2.8, which resulted in 168.89 mg/g of 2,4,6-TCP uptake and 17.96% of activated carbon yield. The experimental results obtained agreed satisfactorily with the model predictions. The activated carbon prepared under optimum conditions was mesoporous with BET surface area of 1141 m(2)/g, total pore volume of 0.6 cm(3)/g and average pore diameter of 2.5 nm. The surface morphology and functional groups of the activated carbon were respectively determined from the scanning electron microscopy and Fourier transform infrared analysis.     

Production of activated carbon from a new precursor molasses by activation with sulphuric acid

Activated carbon has been prepared from molasses, a natural precursor of vegetable origin resulting from the sugar industry in Morocco. The preparation of the activated carbon from the molasses has been carried out by impregnation of the precursor with sulphuric acid, followed by carbonisation at varying conditions (temperature and gas coverage) in order to optimize preparation parameters. The influence of activation conditions was investigated by determination of adsorption capacity of methylene blue and iodine, the BET surface area, and the pore volume of the activated carbon were determined while the micropore volume was determined by the Dubinin-Radushkevich (DR) equation. The activated materials are mainly microporous and reveal the type I isotherm of the Brunauer classification for nitrogen adsorption. The activated carbons properties in this study were found for activation of the mixture (molasses/sulphuric acid) in steam at 750 degrees C. The samples obtained in this condition were highly microporous, with high surface area (> or =1200 m2/g) and the maximum adsorption capacity of methylene blue and iodine were 435 and 1430 mg/g, respectively.     

KOH活化法高比表面积竹质活性炭的制备与表征

以竹屑为原料,研究了KOH活化法高比表面积活性炭的制备工艺.分别考察了浸渍比、活化温度、活化时间等工艺参数对产品吸附性能的影响,并提出了可能的活化机理.在所研究的实验条件下,最佳的制备工艺是浸渍比1.0,活化温度800℃,活化时间2h.所得到的活性炭产品的比表面积和孔容可达2996m2/g和1.64cm3/g.该产品附加值高,在吸附领域特别是在双电层电容器的电极材料领域有广阔的应用前景.     

聚苯乙烯基球形活性炭的制备及其对二苯并噻吩的吸附性能

通过水蒸气活化法制备了聚苯乙烯基球形活性炭,并研究了其对二苯并噻吩(DBT)的吸附性能.采用扫描电镜(SEM)、N2吸附、热重分析(TG)以及液相吸附试验考察了球形活性炭的结构特征.结果表明:以苯乙烯离子交换树脂为原料,通过水蒸气活化法,可以得到比表面积979m2/g～1672m2/g的球形活性炭.其中,BET比表面积和孔容随活化时间和水蒸气流量的增加而增大,而孔径小于0.7 nm的窄微孔却减小.球形活性炭对DBT的吸附量可达109.36mg/g,吸附量与比表面积和总孔容关系不大,而与小于0.7nm的窄微孔成正比.球形活性炭在对DBT的吸附过程中存在不可逆吸附.球形活性炭所含窄微孔的孔容越大,脱附所需要的温度越高,不可逆吸附量越大.     

Optimization of basic dye removal by oil palm fibre-based activated carbon using response surface methodology

Oil palm fibre was used to prepare activated carbon using physiochemical activation method which consisted of potassium hydroxide (KOH) treatment and carbon dioxide (CO(2)) gasification. The effects of three preparation variables: the activation temperature, activation time and chemical impregnation (KOH:char) ratio on methylene blue (MB) uptake from aqueous solutions and activated carbon yield were investigated. Based on the central composite design (CCD), a quadratic model and a two factor interaction (2FI) model were respectively developed to correlate the preparation variables to the MB uptake and carbon yield. From the analysis of variance (ANOVA), the significant factors on each experimental design response were identified. The optimum activated carbon prepared from oil palm fibre was obtained by using activation temperature of 862 degrees C, activation time of 1h and chemical impregnation ratio of 3.1. The optimum activated carbon showed MB uptake of 203.83mg/g and activated carbon yield of 16.50%. The equilibrium data for adsorption of MB on the optimum activated carbon were well represented by the Langmuir isotherm, giving maximum monolayer adsorption capacity as high as 400mg/g at 30 degrees C.     

Analysis of Various Experimental Methods and Preparation of Mesoporous Activated Carbon Powders from Sawdust Using Phosphoric Acid

A critical analysis of various reported experimental methods utilized for preparation of activated carbon using phosphoric acid was attempted to identify the right choice of experimental method. The various experimental methods were grouped into three major categories; of these, a two-stage activation process with the precursor exposed to preset furnace temperature in a self-generated atmosphere was identified to be a suitable method. Accordingly, activated carbon powders were prepared utilizing a two-stage activation process, covering the effect of activation time at 500°C with an impregnation ratio of 1.5. The samples were subjected to adsorption using methylene blue dye, and the adsorption capacity was found to increase with increase in activation time. An adsorption capacity greater than 400 mg/g of activated carbon shows highly developed pores, with pore size higher than 1.5 nm signifying its economical application to commercial liquid-phase adsorption processes. The adsorption isotherms were found to match well with the Langmuir isotherm model with correlation coefficient (r²) greater than 0.95 as compared to the Freundlich isotherm model with r² less than 0.8.     

Physical and chemical properties and adsorption type of activated carbon prepared from plum kernels by NaOH activation

Activated carbon was prepared from plum kernels by NaOH activation at six different NaOH/char ratios. The physical properties including the BET surface area, the total pore volume, the micropore ratio, the pore diameter, the burn-off, and the scanning electron microscope (SEM) observation as well as the chemical properties, namely elemental analysis and temperature programmed desorption (TPD), were measured. The results revealed a two-stage activation process: stage 1 activated carbons were obtained at NaOH/char ratios of 0-1, surface pyrolysis being the main reaction; stage 2 activated carbons were obtained at NaOH/char ratios of 2-4, etching and swelling being the main reactions. The physical properties of stage 2 activated carbons were similar, and specific area was from 1478 to 1887m(2)g(-1). The results of reaction mechanism of NaOH activation revealed that it was apparently because of the loss ratio of elements C, H, and O in the activated carbon, and the variations in the surface functional groups and the physical properties. The adsorption of the above activated carbons on phenol and three kinds of dyes (MB, BB1, and AB74) were used for an isotherm equilibrium adsorption study. The data fitted the Langmuir isotherm equation. Various kinds of adsorbents showed different adsorption types; separation factor (R(L)) was used to determine the level of favorability of the adsorption type. In this work, activated carbons prepared by NaOH activation were evaluated in terms of their physical properties, chemical properties, and adsorption type; and activated carbon PKN2 was found to have most application potential.     

Textural development of sugar beet bagasse activated with ZnCl2

In this study, activated carbons were prepared from sugar beet bagasse, which is side product and waste in sugar plants, by chemical activation with ZnCl2. Influence of activation temperature was investigated on to pore structure. ZnCl2/sugar beet bagasse ratio (impregnation ratio) was selected as 1:1. The impregnated sample was raised to the activation temperature under N(2) (100ml/min) atmosphere with 10 degrees C/min heating rate and hold at this temperature for 1h. The activation temperature was varied over the temperature range of 400-900 degrees C. BET surface area values were determined in the range of 832-1697 m(2)/g. Under the experimental conditions, 500 degrees C was found to be the optimal condition for producing high surface area carbons with ZnCl2 activation. Sugar beet bagasse was suitable for preparation of activated carbon with essentially microporous structure. Activated carbon ash content was found in the range of 1.2-2.7 (%w/w d.b.). Activated carbon samples and raw material were characterized by XRD, FT-IR, DTA and TGA.     

水热炭化-KOH活化制备核桃壳活性炭电极材料的研究

以核桃壳为原料,经水热炭化-KOH活化制备活性炭,并将其用作超级电容器电极材料。采用低温氮气吸附、扫描电镜(SEM)及X射线光电子能谱(XPS)等手段系统研究核桃壳活性炭的微观结构及表面化学性质,并利用恒流充放电、循环伏安等探讨其对应电极材料的电化学性能。研究表明,在碱碳比为3∶1、活化温度为800℃、活化时间为1h的条件下,核桃壳水热炭经KOH活化可制备出比表面积为1 236m2/g、总孔容为0.804cm3/g、中孔比例为38.3%的活性炭。该核桃壳活性炭用作电极材料在KOH电解液中具有优异的电化学特性,其在50mA/g电流密度下的比电容可达251F/g,5 000mA/g电流密度下的比电容为205F/g,且具有良好的循环稳定性,1 000次循环后比电容保持率达92.4%,是一种比较理想的超级电容器电极材料。核桃壳活性炭优异的电化学性能与其相互贯通的层次孔结构和独特的含氧表面密切相关。