中药渣基活性炭的制备及其对头孢拉定的吸附研究

以香橼、桂枝和板蓝根3种中药渣为原料,Na₂CO₃为活化剂,800℃下活化1.5 h制备了香橼活性炭（AC-CM）、桂枝活性炭（AC-RC）和板蓝根活性炭（AC-IT）3种活性炭。采用扫描电镜、红外光谱、比表面积分析、pH值和pH_pzc测定等表征手段考察了活性炭的特性。研究了3种活性炭对头孢拉定的吸附动力学与吸附等温线,考察了不同初始pH值和NaCl质量浓度对吸附过程的影响。结果发现,AC-CM、AC-RC和AC-IT的比表面积分别为453.32、413.78和230.06 m²/g,pH值分别为9.70、8.23和9.24,pH_pzc值分别为9.28、9.21和9.38,活性炭表面主要含有C=O、C=C以及含N基团,SEM分析显示活性炭表面存在大量的孔结构。AC-CM、AC-RC和AC-IT对头孢拉定的吸附过程均符合伪二级动力学与粒内扩散模型,吸附速率受粒内扩散机制和化学吸附共同控制。Freundlich模型能较好地描述3种活性炭的等温吸附过程,n均大于1,说明吸附过程容易进行。溶液初始pH值对活性炭吸附影响较大,pH值为3（在100 mg/L头孢拉定溶液中,添加0.1 g活性炭,吸附48 h）时,AC-CM、AC-RC和AC-IT对头孢拉定的吸附量最大,分别达到74.76、79.44和62.55 mg/g。溶液中NaCl的存在也增加了活性炭的吸附量。     

改性活性炭对甲基橙的吸附

用盐酸和氨水对活性炭进行改性获得改性活性炭,将其用于处理甲基橙废水,考察了改性条件、振荡速度和温度等因素对甲基橙吸附性能的影响,采用吸附等温模型和吸附动力学模型进行拟合,并分析吸附过程的热力学特征. 结果表明,盐酸改性活性炭对甲基橙的吸附效果优于氨水改性活性炭,在甲基橙初始浓度60 mg/L、溶液体积50 mL、温度20℃、振荡速度100 r/min、盐酸改性活性炭投加量0.2 g时,24 h基本达到吸附平衡,甲基橙去除率为93.7%. 不同温度下,盐酸改性活性炭对甲基橙的吸附符合Langmuir(RC2>0.95)和Freundlich(RC2>0.97)吸附等温模型,饱和吸附量达112.7 mg/g. 热力学参数DG0<0,DH0>0,DS0>0,表明盐酸改性活性炭对甲基橙的吸附是自发吸热反应,其吸附动力学可用准二级动力学方程描述,随振荡速度增加,吸附速率常数增加.     

Coniferous Wood Sawdust-based Activated Carbons as Adsorbents Obtained with the Use of Microwave Radiation

Activated carbons were prepared by physical and direct activation of sawdust pellets coming from coniferous trees, with the use of microwave radiation. The activated carbons obtained were used as adsorbents for the removal of methylene blue (MB) from aqueous solutions. Liquid-phase adsorption experiments were conducted and the maximum adsorption capacity of each activated carbon sample was determined. The effects of activation procedure as well as adsorption tests parameters i.e., temperature, pH, initial methylene blue concentration, and contact time on the sorption capacity of each activated carbon were investigated. The kinetic models for MB adsorption on the activated carbons were also studied. Better fit to the experimental data was obtained with the Langmuir isotherm than Freundlich one, for all samples.     

Preparation and Characterization of Activated Carbon from Chestnut Shell and its Adsorption Characteristics for Lead

Activated carbons were prepared from chestnut shell by phosphoric acid activation and the prepared activated carbons were used to remove lead(II) from aqueous solutions. The effects of impregnation ratio (IR) and activation temperature on activated carbon production were investigated. The produced activated carbons were characterized by N₂ adsorption, scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques. The highest surface area (1611 m²/g) and total pore volume (0.7819 cm³/g) were obtained at a carbonization temperature of 500°C with an impregnation ratio of 3/1. The resulting activated carbon was used for removal of lead(II) from aqueous solution. The effects of temperature, contact time, and adsorbent dosage were investigated. The adsorption isotherm studies were carried out and the obtained data were analyzed by the Langmuir, Freundlich, and Temkin equations. The rate of adsorption was found to conform to the pseudo-second-order kinetic model. The Langmuir isotherm equation showed better fit for all temperatures and the maximum adsorption capacities of lead(II) was obtained as 138.88 mg/g at 45°C.     

Removal of pyridine derivatives from aqueous solution by activated carbons developed from agricultural waste materials

The paper investigates the ability of activated carbons developed from coconut shell to adsorb α-picoline, β-picoline, and γ-picolin from aqueous solution. The developed carbons are designated as SAC (activated carbon derived from coconut shells with out any treatment) and ATSAC (activated carbon derived from acid treated coconut shells). The carbons were, characterized and utilized for the sorption of α-picoline, β-picoline, and γ-picoline at different temperatures, particle size, pH and solid to liquid ratio. All the studies were performed by batch method to determine various equilibrium and kinetic parameters. The Langmuir and Freundlich isotherm models were applied and the Langmuir model was found to best report the equilibrium isotherm data. The adsorption of α-, β-, and γ-picoline followed the pseudo-second order rate kinetics. On the basis of kinetic studies, various rate and thermodynamic parameters such as effective diffusion coefficients, activation energy and activation entropy were evaluated. It was concluded that in majority of cases, the adsorption is controlled by particle diffusion at temperatures 10° and 25 °C while at 40 °C it is controlled by film diffusion mechanism. Similarly at concentrations 25 and 50 mg/l the adsorption was governed by particle diffusion in most of the cases while at >50 mg/l it was film diffusion controlled. The overall capacity of ATSAC was higher than SAC. The sorption capacity of γ-picoline was found more followed by β-picoline and α-picoline.     

Use of chemically activated cotton nut shell carbon for the removal of fluoride contaminated drinking water:Kinetics evaluation☆

Chemically activated cotton nut shell carbons (CTNSCs) were prepared by different chemicals and they were used for the removal of fluoride from aqueous solution. Effects of adsorption time, adsorbent dose, pH of the solution, initial concentration of fluoride, and temperature of the solution were studied with equilibrium, ther-modynamics and kinetics of the adsorption process by various CTNSC adsorbents. It showed that the chemical y activated CTNSCs can effectively remove fluoride from the solution. The adsorption equilibrium data correlate well with the Freundlich isotherm model. The adsorption of fluoride by the chemical y activated CTNSC is spon-taneous and endothermic in nature. The pseudo first order, pseudo second order and intra particle diffusion kinetic models were applied to test the experimental data. The pseudo second order kinetic model provided a better correlation of the experimental data in comparison with the pseudo-first-order and intra particle diffusion models. A mechanism of fluoride adsorption associating chemisorption and physisorption processes is presented allowing the discussion of the variations in adsorption behavior between these materials in terms of specific surface area and porosity. These data suggest that chemically activated CTNSCs are promising materials for fluoride sorption.     

Study to investigate the importance of mass transfer of naproxen sodium onto activated carbon

In the present study, the adsorption of naproxen sodium onto activated carbons (BK4, obtained from white polymeric waste and SK4, obtained from black polymeric waste) was investigated by calculating the parameters of pH, contact time, the concentration of naproxen sodium and the temperature. The adsorption data of naproxen sodium onto activated carbon follows the Langmuir isotherm model and its kinetic processes were described by various kinetic adsorption models. It was determined that the pseudo-second-order model was the best choice among all the available kinetic models to describe the adsorption behaviour of naproxen sodium onto activated carbon. During the present study, the intraparticle diffusion rate constant, the external mass transfer coefficient and the film and pore diffusion coefficient were evaluated at various temperatures. In addition, the thermodynamic parameters of the adsorption of naproxen sodium onto activated carbon were also calculated.     

化学师范专业活性炭吸附亚甲基蓝综合实验

为提高化学(师范)专业学生的综合实验能力,设计了"活性炭吸附亚甲基蓝"物理化学综合实验.以活性炭为吸附剂,亚甲基蓝( MB) 为吸附质,考察了吸附剂用量、吸附时间、 温度对活性炭去除亚甲基蓝的影响.探讨了水溶液中活性炭固体颗粒吸附阳离子有机染料亚甲基蓝的吸附热力学(吸附等温线类型)、吸附动力学方程和盐酸脱附条件.结果表明,活性炭对亚甲基蓝染料的热力学吸附行为符合 Langmuir 等温吸附方程,其动力学吸附行为符合准一级动力学方程.选择1:1浓盐酸未能有效的将吸附的亚甲基蓝脱附.     

对苯二甲酸氧化残渣中的有色杂质在活性炭上的吸附规律

为了去除对苯二甲酸氧化残渣中的有色杂质,考察了活性炭类型、吸附温度及溶剂体系含水量对吸附过程的影响.结果表明:以二甲基亚砜作为溶剂的吸附体系中,有色杂质在活性炭上的吸附遵循Langmuir吸附规律;不同类型的活性炭AC-1(木质)与AC-2(煤质)的吸附性能具有不同的温度敏感性,温度对AC-2影响更显著;在溶剂体系中加少量的水有利于杂质吸附.     

花生壳活性炭的表征,表面改性及吸附脱除水中Pb2+离子

Metal ion contamination of drinking water and waste water, especially with heavy metal ion such as lead, is a serious and ongoing problem. In this work, activated carbon prepared from peanut shell (PAC) was used for the removal of Pb2 from aqueous solution. The impacts of the Pb2 adsorption capacities of the acid-modified carbons oxidized with HNO3 were also investigated. The surface functional groups of PAC were confirmed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Boehm titration. The textural properties (surface area, total pore volume) were evaluated from the nitrogen adsorption isotherm at 77K. The experimental results presented indicated that the adsorption data fitted better with the Langmuir adsorption model. A comparative study with a commercial granular activated carbon (GAC) showed that PAC was 10.3 times more efficient compared to GAC based on Langmuir maximum adsorption capacity. Further analysis results by the Langmuir equation showed that HNO3 [20% (by mass)] modified PAC has larger adsorption capacity of Pb2 from aqueous solution (as much as 35.5mg.g1). The adsorption capacity enhancement ascribed to pore widening, increased cation-exchange capacity by oxygen groups, and the promoted hydrophilicity of the carbon surface.     

Investigation of adsorption of lead,mercury and nickel from aqueous solutions onto carbon aerogel

Recently a new form of activated carbon has appeared: carbon aerogel (CA). Its use for the removal of inorganic (and especially metal ions) has not been studied. In the present study, the adsorption of three metal ions, Hg(II), Pb(II) and Ni(II), onto carbon aerogel has been investigated. Batch experiments were carried out to assess adsorption equilibria and kinetic behaviour of heavy metal ions by varying parameters such as agitation time, metal ions' concentration, adsorbent dose and pH. They facilitated the computation of kinetic parameters and maximum metal ion adsorption capacities. Increasing the initial solution pH (2–10) and carbon concentration (50–500 mg per 50 cm³) increases the removal of all three metal ions. A decrease of equilibrium pH with an increase of metal ion concentration led us to propose an adsorption mechanism by ion exchange between metal cations and H⁺ at the carbon aerogel surface. Carboxylic groups are especially involved in this adsorption mechanism. Langmuir and Freundlich isotherm models were used to analyse the experimental data of carbon aerogel. The thermodynamics of the metal adsorption was also investigated for the practical implementation of the adsorbent. The sorption showed significant increase with increase of temperature. Kinetics models describing the adsorption of Hg(II), Pb(II) and Ni(II) ions onto carbon aerogel have been compared. Kinetics models evaluated include the pseudo‐first order and second order model. The parameters of the adsorption rate constants have been determined and the effectiveness of each model assessed. The result obtained showed that the pseudo‐second order kinetic model correlated well with the experimental data and better than the pseudo‐first order model examined in the study. Mass transfer coefficients obtained can be useful in designing wastewater treatment systems or in the development of environmental technologies. Copyright © 2005 Society of Chemical Industry     

二苯并呋喃在活性炭床层中的吸附动力学

The adsorption of dibenzofuran （DBF） on three commercial granular activated carbons （GAC） was investigated to correlate the adsorption equilibrium and kinetics with the morphological characteristics of activated carbons. Breakthrough experiment was conducted to determine the isotherm and kinetics of dibenzofuran on the activated carbons. All-the experiment runs were performed in a fixed bed with a process temperature of 368 K. The effects of adsorbent morphological properties on the kinetics of the adsorption process were studied. The equilibrium data are found satisfactory fitted to the Langmuir isotherm. An intraparticle diffusion model based on the obtained Langmuir isotherm was＇developed for predicting the fixed bed adsorption of dibenzofuran. The result indicated that this model fit all the breakthrough curves well. The surface diffusion coefficients of dibenzofuran on the activated carbon are calculated, and a relationship with the microporosity is found. As it was expected, the dibenzofuran molecule finds more kinetic restrictions for the diffusion in those carbons with narrower pore diameter.     

Equilibrium and Kinetic Studies for Fluoride Adsorption from Water on Zirconium Impregnated Coconut Shell Carbon

Abstract

The batch adsorptive fluoride removal from water by Zirconium ion impregnated coconut shell carbon (ZICSC) was investigated. ZICSC was found to have fluoride adsorption capacity, 25 to 30 times that of plain activated carbon. The effect of various parameters such as pH, agitation time, and adsorbent dosage on fluoride removal were studied. The fluoride adsorption by ZICSC was above 90% for the entire pH range of 2–9 and the adsorption rate was extremely rapid, with 91% of the adsorption being achieved within 10 min of ZICSC contact for an initial fluoride concentration of 10 mg/L. The experimental data have been analyzed by Langmuir, Freundlich, Redlich‐Peterson, and Temkin sorption isotherm models and the adsorption data for fluoride onto ZICSC were better correlated to the Langmuir isotherm. The batch adsorption kinetics have been tested by first order, pseudo‐first order, and pseudo‐second order kinetic models with the subsequent determination of the rate constants of adsorption. The comparison of ZICSC with other adsorbents suggests that ZICSC provides a cost‐effective working solution to the defluoridation problem in the developing countries by its great potential application in fluoride removal from water.     

Relation between the adsorbed quantity and the immersion enthalpy in catechol aqueous solutions on activated carbons

An activated carbon, Carbochem(TM)-PS230, was modified by chemical and thermal treatment in flow of H(2), in order to evaluate the influence of the activated carbon chemical characteristics in the adsorption of the catechol. The catechol adsorption in aqueous solution was studied along with the effect of the pH solution in the adsorption process of modified activated carbons and the variation of immersion enthalpy of activated carbons in the aqueous solutions of catechol. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and pH 7, 9 and 11 in order to evaluate the adsorption value above and below that of the catechol pK(a). The adsorption capacity of carbons increases when the solution pH decreases. The retained amount increases slightly in the reduced carbon to maximum adsorption pH and diminishes in the oxidized carbon. Similar conclusions are obtained from the immersion enthalpies, whose values increase with the solute quantity retained. In granular activated carbon (CAG), the immersion enthalpies obtained are between 21.5 and 45.7 J·g(-1) for catechol aqueous solutions in a range of 20 at 1500 mg·L(-1).     

椰壳炭对肌酐吸附性能及动力学研究

采用水蒸气活化法制备得到微孔发达的椰壳活性炭,并研究其对肌酐的吸附性能。以850℃活化所得微孔率最高的活性炭为吸附剂,考察了活性炭投加量、吸附时间、溶液pH值及肌酐初始质量浓度对肌酐吸附性能的影响,并采用准一级、准二级动力学方程对实验数据进行拟合处理。结果表明,制备所得4种椰壳活性炭对肌酐均有较强的吸附能力;微孔率越高,吸附量越大;37℃下,椰壳活性炭对肌酐的吸附平衡时间为6 h,平衡吸附量达到97.88 mg/g;酸性环境更有利于肌酐吸附;平衡吸附量随肌酐初始质量浓度增加而升高;吸附过程符合准二级动力学模型,以化学吸附为主。     

Vanadium(V) Removal by Adsorption onto Activated Carbon Derived from Starch Industry Waste Sludge

This study examines the adsorption potential of activated carbons for vanadium (V) removal from aqueous solution. Activated carbons were produced via chemical activation of waste treatment sludge from the starch industry. Specific surface area and pore sizes of waste sludge samples were determined through chemical activation and pyrolysis. Experimental data indicated that sludge samples had micropore structure and specific surface area of up to 1196 m²/g. First-order and second-order models were applied to determine adsorption kinetics. Freundlich, Langmuir, and Dubinin–Radushkevich isotherms were used to analyze equilibrium data of adsorption. Equilibrium adsorption data showed the best fit to the Freundlich isotherm. Adsorption of vanadium (V) follows second-order kinetic models. Maximum adsorption was observed at pH 4.0. Langmuir adsorption capacity was found to be 37.17 mg/g. The results of the study indicated that activated carbon obtained from industrial sewage sludge was effective in removing vanadium from aqueous solutions, which creates a significant advantage for treatment of industrial wastewaters and management of solid wastes.     

二苯并呋喃在活性炭上的吸附相平衡和动力学

The adsorption of dibenzofuran on three commercial granular activated carbons （ACs） was investigated by dynamic experiment to correlate the adsorption equilibrium and kinetics with the structure of activated carbons. Physical properties including surface area, average pore diameter, micropore area and micropore volume of the activated carbons were characterized by N2 adsorption experiment on ASAP2010. To calculate the adsorption parameters, adsorption isotherm data were fitted to the Langmuir equation, and adsorption kinetic data were fitted to the linear driving force （LDF） diffusion model. From the correlation results, it is concluded that the adsorption equilibrium and diffusion coefficient of dibenzofuran on activated carbon are controlled respectively by the total adsorbent surface area and the adsorbent pore diameter.     

苯在改性活性炭上的脱附活化能

采用浸渍法制备了KH560/改性活性炭、1706/改性活性炭和A172/改性活性炭等3种活性炭,并利用程序升温脱附技术测定了苯在这3种改性活性炭上的脱附活化能. 结果表明,苯在经改性的活性炭上的脱附活化能均大于其在未改性活性炭上的脱附活化能,表明用有机硅烷改性活性炭可以提高其对苯的吸附能力. IGC分析结果表明,经硅烷改性的活性炭的特殊作用吸附自由能DGs均小于原始活性炭的DGs,这4种活性炭表面与苯的特殊作用吸附自由能DGs大小顺序与苯在这些活性炭上的脱附活化能大小顺序正好相反,这表明DGs越小,吸附质与活性炭表面形成的吸附越牢固,吸附质从其表面脱附所需的活化能越大.     

Adsorption Behavior of Organic Dyes in Biopolymers Impregnated with H3PO4: Thermodynamic and Equilibrium Studies

A lignocellulose‐based waste biopolymer was impregnated with phosphoric acid and used for the removal of two organic dyes, Direct Blue (DB) and Reactive Blue (RB), from aqueous solution. Batch adsorption kinetic studies were carried out at different initial concentrations of the dyes, at different temperatures and various initial pH values (2–10). The equilibrium data obeyed the Langmuir isotherm model with high regression coefficient. The kinetic data were also used to test three different kinetic models. The validity of the kinetic models was analyzed and the pseudo‐second‐order model may be the best fit to explain the rate‐determining step. Adsorption of both dyes follows chemisorption. The effective diffusion coefficient and the activation energy were also calculated at different temperatures to establish the mechanism. Thermodynamic studies suggest that the adsorption of DB and RB is highly endothermic in nature. Mass transfer analysis reveals that the adsorption of DB and RB occurs through a film diffusion mechanism. Based on the Langmuir isotherm equation, the single‐stage batch absorber design of the adsorption of DB and RB onto activated carbon was studied.     

Study of adsorption behavior using activated carbon for removal of colored impurities from 30% caprolactam solution produced by means of SNIA-toluene-technology

We studied the adsorption removal of the colored impurities from caprolactam solution by granular activated carbons. It was observed that removal was favored at lower pH (pH 3.84 or below) and higher temperature. The effects of concentration, dosage of activated carbons, contact time have been also reported. Uptake of colored impurities was very rapid in the first 100 minutes and reached equilibrium after 24 h. The batch adsorption kinetics was found to follow the pseudo-second-order model and the rate constants of adsorption for all these kinetic models have been calculated. Three isotherm expressions Langmuir, Freundlich and Trinomial were shown to fit with the experimental results successfully. The mass transfer coefficientβ and the effective diffusion coefficient in aqueous phase Deff was calculated under a temperature 35–80 °C. The value of the mean free energy of adsorption E signifies that the adsorption of colored impurities onto activated carbon has a physical nature.