改性活性炭对噻吩的吸附性能研究

用过硫酸铵、臭氧对椰壳活性炭和煤基活性炭进行氧化改性,研究了改性活性炭对噻吩的吸附性能,材料结构袁征结果表明,经两种方法氧化处理后,椰壳炭的孔结构基本保持不变,而煤基炭的比表面积和孔容有所增加.Boehm滴定发现氧化后活性炭表面含氧官能团数量增加并由FT-TR图谱得到证实.氧化处理提高了噻吩在活性炭表面的吸附容量与Langmuir和Freundlich两种吸附等温线方程的相关性.采用拟一级、拟二级和粒子内扩散模型速率方程来考察吸附动力学,并计算了这些动力学模型的速率常数,拟二级模型和实验数据之间有较好的相关性.同时对影响吸附性能的因素进行了分析.     

甲醇与异丁烯在改性β分子筛上的吸附行为研究

采用过渡应答技术对甲醇和异丁烯在改性β分子筛上的吸附行为进行了研究,研究结果表明,异丁烯和甲醇在改性β分子筛上符合先快吸附后慢吸附的Elovich吸附规律。甲醇的吸附量大,但速率慢;异丁烯吸附量小,速率快。由于甲醇的饱和吸附量大于异丁烯的饱和吸附量,对合成MTBE反应的选择性具有重要意义,对它们的吸附行为进行动力学研究,得到了不同温度下吸附活化能随吸附量变化的关系。不同温度下相对饱和吸附量预测表明：当温度从288K升高到383K时,qMeOH/q1BWW 6．1降低到4．6,甲醇的相对饱和吸附量随温度升高而减小,但仍保持较高值,证明了甲醇在分子筛上是强吸附的观点,为解释选择性高和动力学方程的建立提供依据,对反应机理的研究有指导作用。     

超高交联树脂吸附二氯乙烷的热效应特性及其对柱吸附的影响

研究了超高交联吸附树脂在恒温和绝热两种条件下对气体中二氯乙烷的动态吸附行为。采用半经验方程Yoon-Nelson模型对穿透曲线数据进行拟合和分析,并探讨了吸附过程中的温升对吸附的影响。实验结果表明,床层的温升随着进气浓度的增加而增加,底层树脂的吸附放热对上层树脂的温升有一定影响,当进气浓度为200mg/L(STP)时,吸附柱最高温升达到48.7℃,此时穿透吸附量相比于恒温吸附下降30.6%,吸附速率常数也明显下降。     

甲醇与异丁烯在改性β分子筛上的吸附行为研究

采用过渡应答技术对甲醇和异丁烯在改性β分子筛上的吸附行为进行了研究,研究结果表明：异丁烯和甲醇有改性β分子筛上符合先快吸附后慢吸附的Elovich吸附规律。甲醇的吸附量大,但速率慢,异丁烯吸附量小,速率快;由于甲醇的饱和吸附量大于异下烯的饱和吸附量,对合成MTBE反应的选择性具有重要意义。对它们的吸附行为进行动力学研究,得到不同温度下吸附活化能随吸附量变化的关系。不同温度下相对饱和吸附量预测表明：当温度从288K升高到383K时,qMeOH/qIB从6．1降低到4．6,甲醇的相对饱和吸附量随温度升高而减小,但仍保持较高值,证明了甲醇在分子筛上是强吸附的观点,为解释选择性和高和动力学方程的建立提供依据,对反应机理的研究有指导作用。     

红霉素在大孔树脂SP825上的固定床吸附动力学研究

通过大孔吸附树脂SP825对红霉素进行动态吸附,研究了进料浓度、温度、床层高度和高径比等因素对穿透曲线的影响,采用同时考虑液膜扩散阻力、孔内扩散阻力和轴向扩散的综合速率模型对吸附过程进行模拟,计算得到相关动力学参数。结果表明,进料浓度的增加对红霉素固定床吸附过程不利,温度和床层高径比的增加可以提高固定床吸附效率,而床层高度的变化对固定床吸附过程影响不大。     

PAN基活性炭纤维床层上有机溶剂蒸汽的穿透特性

本文考察了PAN基活性炭纤维（ACF）床层对低浓度有机溶剂蒸汽的吸附行为，并应用了Yoon—Nelson理论，发现穿透曲线可用改进的方程式来表达，得到了吸附剂ACF2的吸附常数及三氯乙烯、甲苯的总吸附传质系数。     

壳聚糖基磁性树脂对Au^3＋和Ag^＋的吸附 Ⅱ吸附热力学和穿透曲线研究

利用硫脲改性的壳聚糖基磁性微球(TMCS)吸附Au3 和Ag 。利用静态吸附法考察了不同温度下Au3 和Ag 的吸附等温线;利用柱吸附法考察了进液流率、床层高度对穿透曲线的影响。结果表明,随温度升高,Au3 和Ag 的吸附容量下降;焓变(△H°)为负,表明吸附过程放热;Gibbs自由能(△G°)为负,表明吸附反应能自发进行。随进液流率增加或床层高度下降,穿透曲线前移;由BDST模型(Beddepth service time model)得出的临界床层高度分别为:Au3 2.34cm;Ag 3.41cm。TMCS有良好的重复使用性。     

改性埃洛石材料的制备及其对亚甲基蓝吸附行为的研究

使用硅烷偶联剂KH550改性埃洛石纳米管获得改性材料HNTs-APTS,并对其吸附亚甲基蓝的行为进行研究。利用傅立叶变换红外光谱仪(FTIR)、X-衍射仪(XRD)对改性前后的埃洛石进行表征。考察了吸附时间和温度对吸附过程的影响,并采用Lagrange准二级动力学方程、Langmuir等温线方程及Freundlich等温线方程对实验数据进行拟合。结果表明,KH550成功负载到埃洛石表面;改性后材料的吸附能力大大提高。改性埃洛石对亚甲基蓝的吸附约在60 min达平衡,最大吸附容量为21.66 mg/g。其吸附过程符合准二级动力学方程,热力学较好地符合Langmuir等温线方程,且吸附过程为自发吸热,升高温度有利于吸附的进行。改性材料可重复再生6次,具有良好的再生性能,可在工业处理亚甲基蓝废水中使用。     

活性炭的改性及对Pb2+的动力学吸附研究

论文以活性炭为主体吸附剂，进行氯化铁改性，制备出氯化铁改性活性炭吸附剂，并通过FT-IR、SEM、比表面积和孔体积进行表征。实验进一步探究改性活性炭对Pb²⁺的吸附能力，结果表明，当吸附时间为300 min,吸附剂投加量为0.4 g, pH为6时，吸附效果最佳。在此吸附条件下，改性活性炭对Pb²⁺的去除率达到91.2%。对改性活性炭吸附Pb²⁺进行动力学吸附研究，结果表明二级速率方程能够更好地描述其动力学吸附过程，吸附的机理可归结为氯化铁改性导致活性炭孔道结构中酸性官能团增加，使得金属阳离子与官能团上的H之间产生离子交换作用，有利于吸附的进行，这一实验结果为后期循环吸附研究提供了新依据。     

硫化钠改性活性炭对Pb(Ⅱ)的吸附性能研究

采用质量分数为3%的Na_2S溶液对活性炭浸渍,在600℃以N_2作为保护气对其进行高温处理,研究Na_2S改性活性炭(SAC)吸附Pb(Ⅱ)的动力学和热力学机理,并对吸附Pb(Ⅱ)前后的改性活性炭进行了表征和分析。结果表明,与改性前活性炭相比,SAC的比表面积和总孔容减小,S元素含量显著提高。SAC对Pb(Ⅱ)的吸附效果显著提高,在Pb(Ⅱ)初始浓度为300mg/L时,SAC对Pb(Ⅱ)最大吸附量为122.56mg/g,并且在吸附过程的前80min内可达到总吸附量的95%以上。SAC对Pb(Ⅱ)的吸附过程可用Langmuir模型描述,动力学特性符合拟二级动力学模型。SAC对Pb(Ⅱ)的吸附的热力学参数ΔG在-80~-20k J/mol之间,ΔH0,ΔS0,表明吸附是自发进行的物理吸附与化学吸附共同作用的放热过程。对吸附前后改性活性炭的傅里叶变换红外谱图分析表明,经过Na_2S改性后,活性炭表面引入了砜基,并且砜基强化了改性活性炭对Pb(Ⅱ)的吸附性能。     

COS hydrolysis in the presence of oxygen： Experiment and modeling

A mathematical model of COS hydrolysis on Al2O3, with fouling of catalyst, has been developed. Kinetic studies were carried out in a fixed bed reactor under atmospheric pressure and low temperature （40-70℃）. The effects of the COS inlet concentration, temperature, and relative humidity were analyzed. Experimental results of breakthrough curves were used to obtain kinetic parameters, which accounted for effects of S deposition on the inner-face of the catalyst. The model described the experimental breakthrough curves satisfactorily and well explained the performance of COS hydrolysis in the presence of oxygen. The exothermic heat of adsorption and activation energy, assuming Arrhenius type of temperature dependence of the equilibrium constant, were determined. Activation energy of COS hydrolysis and H2S oxidation were 35.9 kJ/mol, 19.6 kJ/mol; adsorption heat of H2O and H2S on Al2O3 were 45.1 and 60.1 kJ/mol respectively. Deactivation coefficient （α） was used to quantify the behavior of COS hydrolysis at different operating conditions. The effect of relative humidity on α is significant in the relative humidity range under study. Experimental data accorded well with model data in the studied range.     

Sorptive elimination of fluoride from contaminated groundwater in a fixed bed column: A kinetic model validation based study

The current investigation involves a continuous adsorption experiment in a packed bed column for the sorptive elucidation of fluoride from contaminated groundwater using an activated soil-clay mixture. Through the combination of naturally accessible laterite soil with silica enriched clay (3:1 ratio), a low-cost Al–Si heterogeneous material has been developed. Following detailed characterization, the developed materials were employed in a long-time column process to achieve a high degree of fluoride separation from real-world groundwater. In a packed bed column investigation, the effect of bed height, initial fluoride concentration, and flow rate on the breakthrough properties of the adsorption system were investigated. By using a non-linear regression equation, three model kinetics, such as the Thomas Model, Adams-Bohart Model, and Yoon-Nelson Model, were fitted to validate the column-based experimental data, by analysing the breakthrough curves profiles, and distinct kinetic parameters. The Bed Depth Service Time Analysis (BDST) model was tested to express the effect of bed height on breakthrough curves, as well as to predict the time for breakthrough, and material depletion under optimal conditions. The Thomas and Yoon-Nelson models were identified to be the most appropriate ones for describing the entire breakthrough curve, whereas the Adams-Bohart model was only utilised to predict the first half of the dynamic process. With correlation coefficients (R²) 0.96, the experimental results were well suited to Thomas, Yoon-Nelson, and Adams-Bohart models. Finally, regeneration assessment was carried out where even after four cycles of operation, regenerated adsorbent showed a rejection efficacy of 78% to fluoride that proves the viability of the material and methodology.     

无氧下低浓度硫化氢在浸渍活性炭上的吸附研究

为了考察常温、无氧下浸渍Na2CO3改性、原料气相对湿度对活性炭吸附硫化氢的促进作用，用动态吸附法分别测试了不同湿度下原活性炭和浸渍活性炭对低浓度硫化氢的吸附，同时考察了温度对该吸附过程的影响。结果表明，吸附平衡数据均符合Freundlich吸附等温方程。与原活性炭相比，浸渍活性炭的孔容和比表面积略有降低，但对硫化氢的吸附能力却显著提高，说明硫化氢与浸渍剂在活性炭表面上发生了化学反应。相对湿度增加，活性炭和浸渍活性炭对H2S的吸附能力均显著增强。温度升高，平衡吸附量均略有下降。     

活性炭纤维对气相低浓度三氯乙烯的动态吸附

研究了3种不同经表面积活性炭纤维（ACF）对气相低浓度三氯乙烯（TCE）的动态吸附。ACF的比表面积为600m^2/g、1400m^2／g和1600m^2/g，TCE的浓度范围为27mg/m^3-2725mg/m^3。结果表明，比表面积为1400m^2/g和1600m^2/g的ACF对TCE的吸附较好；10％穿透时间的对数与TCE匠对数呈线性关系；穿透时间随温度和湿度的增加而缩短；穿透曲线可以用经验公式拟合。拟合值和实测值吻合良好；ACF吸附是去除气相低浓度TCE的有效方法。     

Chromium adsorption in olive stone activated carbon

In this work, Cr(III) adsorption on activated carbon obtained from olive stones in an upflow fixed-bed column at 30^∘C was studied. The flow rate influence on the breakthrough curves at a feed concentration of 0.87 meq/L was investigated in an attempt to minimize the diffusional resistances. Breakthrough curves for a flow range of 2–8 mL/min were obtained at 10.5 cm bed height and inlet diameter of 0.9 cm. The mass transfer parameters indicated that the bed minimal resistance was attained at 2 mL/min. Therefore, the data equilibrium was carried out until the bed was saturated at 2 mL/min. The dynamic system generated a favorable isotherm with a maximum chromium uptake of 0.45 meq/g. A column sorption mathematical model was created considering the axial dispersion in the column and the intraparticle diffusion rate-controlling steps. The isotherm was successfully modeled by the Langmuir equation and the mathematical model described the experimental dynamic data adequately for feed concentrations from 0.26 to 3.29 meq/L.     

Adsorption tests of water vapor on synthetic zeolites for an atmospheric detritiation dryer

Tritiated hydrogen and hydrocarbon are usually oxidized to a tritiated water vapor to make the tritium adsorbable and easy to treat. The adsorption system as a subsequent process plays an important role in a tritium recovery and its performance affects the overall detritiation efficiency significantly. In order to quantify an adsorbent's utilization and its dynamic capacity against an inlet humidity and a flow rate, a series of quantitative tests based on the breakthrough behavior were carried out in an isothermal fixed bed of synthetic zeolites such as molecular sieve 4A, 5A, 13X and mordenite. The amount of water vapor breaking during the adsorption was estimated to provide a breakthrough capacity at the various inlet flow rates and humidity conditions. The molecular sieve 13X exhibited a better adsorption performance at a given bed height. The existence of CO₂ in a humid atmosphere had a minor effect on the net adsorption capacity and the hydrogen isotopic water (HDO) in the elution stream showed a delayed behavior during a thermal desorption.     

Competitive effect of glucose–fructose adsorption in a fixed‐bed chromatographic column

A continuous separation system such as a simulated moving‐bed process requires adsorption data with precise equilibrium and kinetic model parameters of a single chromatographic column. The adsorption of glucose and fructose in a fixed‐bed chromatographic column was investigated to determine the competition effect of each component resulting from their initial molar ratios. The model parameters including bed porosity and axial dispersion coefficient were determined using the moment analysis method. The equilibrium isotherm parameters were estimated by conducting experiments at various molar ratios and initial sugar concentrations. The parameters obtained were then used for the simulation of dynamic breakthrough curves of glucose and fructose. The equilibrium isotherms revealed that the linear adsorption pattern provided good prediction for each molar ratio using the Henry equation. In addition, the modified Langmuir model was proposed to account for the competitive adsorption, due to the cooperative competition effect whereby glucose was promoted to the active sites by fructose to a greater degree than vice versa. A good agreement between the experimental and numerical data of the adsorption time profiles was also observed.     

Kinetics of carbon dioxide absorption from air in a flow reactor with a fixed bed of K<Subscript>2</Subscript>CO<Subscript>3</Subscript>-based sorbent

Sorption of carbon dioxide from air in a flow reactor with a bulky fixed bed of the K₂CO₃/Al₂O₃ composite sorbent was studied. The dynamic sorption capacity of the material was shown to depend on the relative humidity of the inlet air. A numerical model was constructed for evaluating the profile of СО₂ concentration in the layer and kinetic curves of CO₂ breakthrough at the outlet of the reactor. The results of simulation allowed us to adequately describe the experimental kinetic curves at 20–40% humidity.     

Use of Wheeler–Jonas equation to explain xenon dynamic adsorption breakthrough curve on granular activated carbon

The Wheeler–Jonas equation (WJ equation) is widely used to predict breakthrough of volatile organic compounds on granular activated carbon (GAC) and the most important criteria is to calculate the overall adsorption rate constant (k _v ) and amount adsorbed based on breakthrough curve. The operational factors, including temperatures, concentrations and flow rates, for packed bed, can affect the values of k _v more or less and to what degree has not yet been systematically investigated. What’s more, the relation between the dynamic adsorption coefficient (k _d) or Henry constant, which is used for the design of packed bed, and WJ equation is not clear. In order to solve these problems, we performed xenon dynamic adsorption on GAC adsorber experiments under different values of xenon concentrations, flow rates and temperatures, obtained the breakthrough curves for elution times versus xenon concentrations, and then employed WJ equation to explain breakthrough curves. The experimental results indicate that the WJ equation can fit the breakthrough curve very well and k _d be integrated into the WJ equation. The values of k _v are proportional to the values of flow rates and k _d, but independent of that of temperatures and xenon concentrations.     

Separation of carbon dioxide/methane mixtures by adsorption on a basic resin

In this work, the separation of carbon dioxide/methane mixtures by PSA using a basic resin (Amberlite IRA-900) has been studied. Adsorption equilibrium and kinetics of carbon dioxide and methane on a fixed-bed of this adsorbent have been measured, and a binary adsorption equilibrium isotherm has been obtained. The adsorbent deactivation with the number of adsorption-desorption cycles, and its regeneration, have also been analysed. A model based on the LDF approximation has been used to describe the experimental breakthrough curves. The applicability of the basic resin to the separation of carbon dioxide/methane mixtures has been studied in an experimental PSA setup using a single bed. The validity of the model used in the fixed-bed study for simulating a PSA system has been checked by comparing the simulated and the experimental performance of the proposed PSA cycle.