D301R树脂对Keggin型铁取代杂多阴离子的吸附性能研究

详细研究了D301R弱碱性阴离子交换树脂对Keggin型铁取代杂多阴离子PW11O39Fe(III)(H2O)4－ (PW11Fe)的吸附作用, 考察了不同pH和温度对吸附量和吸附速率的影响, 测定了不同温度下吸附的动力学曲线和吸附等温线, 提出吸附动力学模型和计算了吸附的热力学函数, 结果表明, 在pH 2～8的范围内, PW11Fe的吸附量随溶液pH值的升高而增加, 随溶液温度的升高而降低; 吸附动力学符合表面过程控制的准二级反应模型, 其速率常数k2在298 K时为 9.33×10－4 g•mg－1•min－1, 并随温度的升高而减小. 吸附等温线符合Freundlich吸附模型, 吸附热约为40 kJ•mol－1, 因此, 吸附为物理吸附.     

邻-氨基酚修饰吸附树脂对2-氨基吡啶的静态吸附热力学及动力学特征

合成了两种邻-氨基酚修饰超高交联吸附树脂(MOAR-1、MOAR-2),并用该树脂对水溶液中2-氨基吡啶的静态吸附热力学和动力学特征进行研究。热力学研究结果表明,Freundlich吸附等温方程能够对静态吸附等温线进行很好地拟合。吸附焓变ΔH<0,其绝对值小于60kJ/mol,表明以物理吸附为主以及该吸附剂容易脱附的特征;ΔG<0,说明吸附是自发行为;ΔS<0,表明吸附质分子在树脂表面上的运动受到了限制。两种树脂对2-氨基吡啶的吸附量随着温度的升高而降低,适当降低温度有利于吸附。动力学研究的结果表明:吸附符合一级动力学方程,吸附速率随温度升高而增大。表观活化能Ea<4.0kJ/mol,说明吸附较容易进行。     

新型离子交换树脂CG-6对人凝血酶原复合物的吸附行为分析及研究

根据人凝血酶原复合物(Prothrombin Complex Concentrate,以下简称PCC)的性质,对合成的大孔阴离子交换树脂进行静态吸附研究,并与已经商品化的DEAE Sephadex A50、Streamline DEAE凝胶型离子交换树脂进行比较,筛选出吸附性能较优的CG-6树脂.通过静态吸附实验,测定了CG-6对PCC在不同温度下的吸附等温线、考察了吸附过程中的动力学和热力学行为并初步探讨了吸附机理.结果表明,吸附动力学可用拟二级速率方程来描述,计算值与实测值吻合较好.CG-6对PCC的吸附等温线可分为两段,在较低的平衡浓度下,吸附平衡符合Langmuir方程,温度的升高有利于平衡吸附量的增大,表明该吸附反应为一吸热过程.求出反应的焓变△H=115.1kJ/mo1,熵变△S分别为2.37J/mol·K(5℃)、20.97 J/mol·K(15℃)、23.11J/mol·K(20℃)、37.32J/mol·K(30℃),吉布斯自由能变化△G分别为-0.54kJ/mol(5℃)、-5.93kJ/mol(15℃)、-6.66kJ/mol(20℃)、-11.20kJ/mol(30℃).此外,除了离子交换,CG-6对PCC也有物理吸附现象.     

大孔树脂对茄尼醇吸附行为的研究

从6种大孔树脂中筛选出用于茄尼醇分离较好的树脂NKA,并进一步研究了其对茄尼醇吸附行为,结果表明,吸附等温线服从Langmuir方程和Freundlich方程,且吸附过程表现为优惠吸附.在温度为283～313K,吸附量为15～35mg/g的条件下,吸附焓变为-16.20～16.57kJ/mol,自由能变为.3.142～3.459kJ/mol,吸附熵变为-47.43～41.17J/mol.K.NKA树脂对茄尼醇吸附速率较快,吸附过程符合一级吸附动力学方程,吸附过程主要受液膜扩散控制.     

聚(N-甲基-N-对乙烯基苄基乙酰胺)对水中苯酚的吸附

由大孔交联氯甲基化聚苯乙烯进行甲胺化和乙酰化反应,合成了聚(N-甲基-N-对乙烯基苄基乙酰胺)树脂,树脂的氯含量由原来的3.95mmol/g降至0.63mmol/g.测定了树脂对水中苯酚的吸附等温线,结果表明,吸附平衡数据符合Freundlich等温方程.利用热力学函数关系计算了吸附焓、吸附自由能和吸附熵,结果表明,吸附量在10～40mg/g时,吸附焓为-71.20～-24.65kJ/mol,吸附自由能为-4.64～-6.07kJ/mol,吸附熵为-62.35～-218.56J/(mol·K).讨论了吸附过程中树脂对水中苯酚吸附的氢键与疏水作用的吸附机理.     

聚羧酸型梳状共聚物超分散剂在氟虫腈颗粒界面的吸附性能

采用紫外光谱(UV)、 傅里叶变换红外光谱(FTIR)、 X射线光电子能谱(XPS)和扫描电子显微镜(SEM)对聚羧酸型梳状共聚物超分散剂(TERSPERSE^®2700)在氟虫腈颗粒界面的吸附等温线、 吸附动力学、 吸附作用力、 吸附层厚度以及吸附状态等进行了分析. 实验结果表明, TERSPERSE^®2700分散剂在氟虫腈颗粒界面的吸附模型符合Langmuir吸附等温式, 吸附量随着温度升高而增大, 并计算了ΔG^0-, ΔH^0-和ΔS^0-. 吸附符合准一级动力学模型, 吸附速率常数随着温度升高而增大, 吸附活化能E_a=29.28 kJ/mol. 利用XPS谱图, 估算其吸附厚度约为1 nm, 表明存在吸附作用. 实验发现氟虫腈存在分子间氢键, 同时氢键也是分散剂分子与氟虫腈颗粒表面结合的重要作用力.     

X-5大孔树脂吸附熊果酸的动力学与热力学特性研究

研究了熊果酸在X-5树脂上吸附的动力学和热力学特性,从物理化学的角度探讨了树脂吸附天然产物的机理。动力学结果表明,在pH=6.36时,熊果酸在X-5树脂上吸附量最大,吸附量为0.1016mmol/g。热力学结果表明,不同温度下熊果酸在X-5树脂上的等温吸附符合Langmuir方程和Freundlich方程,吸附热焓变?Hm=58.77kJ/mol,熵变?Sm=0.23kJ/mol·K,吉布斯自由能?Gm随温度升高向负方向增加。以上热力学参数表明,熊果酸在X-5树脂上的吸附属于自发的物理吸附过程,且在X-5大孔树脂吸附熊果酸过程中,液固界面间增加了随机性吸附。     

巯基功能化膨润土吸附Pb2+的动力学和热力学研究

研究了自制巯基功能化膨润土(TFB)对Pb2+的吸附行为,考察了溶液的pH值、离子强度、吸附时间和温度对吸附平衡的影响,并对吸附过程进行了动力学与热力学研究.结果表明,常温下,吸附时间为60min、0.1mol/L的KNO3、pH=6.0、5.0g/L TFB对200mg/L的Pb2+的吸附率达到85.4％以上,TFB对Pb2+的吸附动力学符合准二级动力学方程;TFB对Pb2+的吸附热力学符合Langmuir等温线方程和Dubinin-Radushkevich (D-R)等温线方程,表明吸附主要发生在TFB表面的活性区域,属于单分子层吸附,其吸附平均活化能E在8-16kJ/mol范围内,表明该吸附过程为化学吸附,不同温度下的吸附热力学的吉布斯自由能以及熵变和焓变表明该吸附过程为自发放热反应.     

芭蕉芋渣对亚甲基蓝的吸附及机理研究

以芭蕉芋渣作为吸附材料,探讨了pH值、温度、亚甲基蓝(MB)初始质量浓度、吸附时间等因素对其吸附MB的影响,利用FT-IR、SEM等技术,结合吸附等温线和动力学模型分析研究了其吸附机理。结果表明,芭蕉芋渣能与阳离子染料亚甲基蓝上的正电荷基团之间形成静电引力,从而产生较好的吸附作用,亚甲基蓝的起始浓度在100～5 000 mg/L,吸附量达到185.0 mg/g。随吸附时间的增加,芭蕉芋渣对亚甲基蓝的去除率增大,180 min后达到平衡;随着温度的升高,吸附量也增大。芭蕉芋渣对亚甲基蓝的吸附作用更符合Redlich-Peterson等温模型;该吸附动力学过程可以用准二级模型进行很好的描述,拟合所得的初始吸附速率随着温度的增加而提高。     

2,4-/2,6-二氨基甲苯在D151树脂上的吸附分离

从10种树脂中筛选出D151树脂对2,4-二氨基甲苯和2,6-二氨基甲苯的吸附分离及其热力学性质进行了研究。 测定了吸附等温线,Freundlich模型对实验的拟合度大于Langmuir模型,其相关系数大于0.99。 热力学研究结果表明,在293～313 K条件下,初始质量浓度为60～80 g/L时,2,4-二氨基甲苯的吸附焓变为-4.3490～-5.7558 kJ/mol,自由能变为-0.2911～-1.0346 kJ/mol,吸附熵变为-12.965～-16.150 J/(mol·K);而2,6-二氨基甲苯的吸附焓变为-2.9645～-3.6054 kJ/mol,自由能变为-0.1610～-0.6384 kJ/mol,吸附熵变为-7.939～-11.005 J/(mol·K)。 进一步研究了D151树脂对二氨基甲苯的动态吸附分离,可以将2,6-二氨基甲苯含量从20%提高至99.93%,将2,4-二氨基甲苯含量从80%提高至99.42%。     

Elution and frontal dynamics of adsorption of organic substances on activated carbon

The elution dynamics of adsorption on activated carbon was studied at various carrier-gas flow rates for a series of organic substances. With the help of the model of the equilibrium adsorption layer that uses the adsorption isotherm described by the theory of volume filling of micropores the outlet curves for the elution and frontal dynamics of adsorption can be adequately predicted. The effective kinetic coefficient and the parameters of the adsorption isotherm were found to be constant for the elution curves calculated both in the elution and frontal regimes of the adsorption dynamics over the whole range of concentrations studied. The effective kinetic coefficient in the mathematical model employed for the systems with microporous adsorbents is independent in fact of the nature of an adsorptive and is mainly determined by the parameters of porous structure of activated carbon and the experimental conditions of a dynamic run.     

Why Does the Linear Driving Force Model for Adsorption Kinetics Work?

The Linear Driving Force (LDF) model for gas adsorption kinetics is frequently and successfully used for analysis of adsorption column dynamic data and for adsorptive process designs because it is simple, analytic, and physically consistent. Yet, there is a substantial difference in the characteristics of isothermal batch uptake curves on adsorbent particles by the LDF and the more rigorous Fickian Diffusion (FD) model. It is demonstrated by using simple model systems that the characteristics of the adsorption kinetics at the single pore or the adsorbent particle level are lost in (a) evaluating overall uptake on a heterogeneous porous solid, (b) calculating breakthrough curves from a packed adsorbent column, and (c) establishing the efficiency of separation by an adsorptive process due to repeated averaging of the base kinetic property. That is why the LDF model works in practice.     

Elution dynamics of adsorption of Chladon 113 and methyl bromide on active carbons

The elution dynamics of adsorption of Chladon 113 (at high contents of the adsorptive) and methyl bromide on active carbons with different lengths of the layer was studied. The adsorption isotherms were described by the equation of the theory of volume filling of micropores. The elution curves were calculated using the model of the equilibrium adsorption layer. The effective kinetic constant calculated in the framework of the model is 1.5 cm for Chladon 113 at a linear velocity of vapor-air flow of 1250 cm min⁻¹ and 1.0 cm for methyl bromide at the velocity of 700 cm min⁻¹. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1353–1355, July, 1998.     

Kinetic and Thermodynamic Study on the Liquid Phase Adsorption by Starchy Materials in the Alcohol-Water System

Improving adsorptive processes demands a constant search for new adsorbents. In the case of alcohol-water separation, zeolites are widely used. The use of new adsorbents as a substitute for zeolites, mainly starch, has been proposed recently. This work is a thermodynamic and kinetic study of liquid phase adsorption of water from methanol, ethanol, propanol and butanol-water mixtures using starch as the adsorbent. The thermodynamic data were obtained by means of the static method at three different temperatures (25, 40 and 50°C), and were correlated by the Langmuir isotherm. The kinetic data were obtained in a finite liquid bath cell. The influence of temperature and molecular chain length of the alcohol on the capacity and adsorption rate were determined.     

甲苯在多级孔丝光沸石上的吸附平衡和吸附动力学

为了考察多级孔丝光沸石中介孔的存在对丝光沸石吸附平衡和动力学的影响,选择甲苯分子作为探针分子,对其在具有不同介孔孔隙度的多级孔丝光沸石上的吸附等温线和吸附动力学曲线进行了测试。结果表明,甲苯在多级孔丝光沸石上的吸附等温线可以很好地用双位Toth吸附模型进行描述,由拟合参数以及亨利常数（K_H）和初始吸附热（Q_st）的计算得知,相对于微孔丝光沸石,介孔的引入增大了甲苯在丝光沸石内的吸附量,但减弱了甲苯与沸石表面的相互作用力;另外,甲苯在多级孔沸石表现出高的吸附速率,并随介孔孔隙度的增加而增大,反映了沸石内介孔的存在可有效促进沸石的传质能力。     

A composite metal-organic framework material with high selective adsorption for dibenzothiophene

A composite metal-organic framework material Ag⁺/MOF-101 was synthesized and applied to adsorb dibenzothiophene (DBT) from model oils. The loading of Ag⁺ enhanced the deep adsorptive desulfurization capacity for DBT and significantly weaken the adsorption competitiveness of toluene.     

多壁碳纳米管对微量苯二氮卓类药物的吸附性能研究

研究了静态吸附条件下多壁碳纳米管(MWCNTs)对地西泮、艾司唑仑、阿普唑仑和三唑仑 4种苯二氮卓类药物的吸附性能,10 min内能达到吸附平衡.MWCNTs对药物的吸附容量随药物浓度的增加而增加,最小初始浓度时MWCNTs对4种药物的静态吸附容量分别为7.95、7.88、7.99和7.73 mg/g,吸附容量较大.295、303和313 K温度下的吸附实验表明,吸附容量随温度的升高而减小,降低温度有利于药物的吸附.对不同温度下的吸附等温线采用Freundlich和Langmuir方程进行拟合,结果显示Langmuir方程具有更好的拟合效果.在动态吸附条件下穿透体积的测定显示MWCNTs对药物也具有大的吸附容量且萃取回收率高达90%以上.     

树脂吸附法分离银杏酚酸的研究

采用树脂吸附法分离银杏酚酸，通过对5种不同类型的树脂的筛选，发现D290树脂对银杏酚酸类有较大的吸附量。对D290树脂对银杏酚酸的吸附性能进行了研究，得到了吸附等温线、动力学曲线、穿透曲线，同时对不同浓度的乙酸石油醚溶液对解吸率的影响进行了研究，发现1％的乙酸石油醚溶液洗脱较好，解吸率为95％。     

Dynamic surface tension behavior of aqueous solutions ofN-dodecyl-N,N dimethyl aminobetaine chlorohydrate

The adsorption behavior ofN-dodecyl-N,N dimethyl aminobetaine chlorohydrate (DDAB·HCl) at the air/aqueous interface was studied for solutions in pure water and phosphate buffer (pH=7.4). The equilibrium surface tension versus concentration curves were used to estimate the equilibrium adsorption parameters and CMCs. The buffer solution has a lower CMC and shows higher surface activity below the CMC than the pure water solution. Data and calculations of the dynamic tension behavior at constant-area conditions showed that the adsorption processes of DDAB·HCl solutions are about 10 to 300 times slower than those predicted by a diffusion-controlled model. A mixed kinetics adsorption model with a modified Langmuir-Hinshelwood kinetic equation, which considers an activation energy barrier for adsorption, was applied to find the kinetic adsorption parameters. The dynamic tension behavior at pulsating-area conditions with large amplitude was also examined for frequencies up to 90 cycles/min. The tension amplitude responses depended strongly on the concentration and frequency. Comparisons of diffusion-controlled model predictions and pulsating area tension data confirmed the need to use a mixed kinetics model. The latter model can improve the fit over the diffusion-controlled model, but it does not quantitatively match the observed tensions.