Divalent Amino Acid Adsorption on Cation Exchange Resin

Abstract

Mass transport of divalent amino acids, arginine and histidine, was investigated in an ion exchange system using DIAION SK104, SK1BL, and SK112. Ion exchange equilibrium constants of arginine were 5.0 g/cm³ for SK104 (4 wt% D.V.B.), 25.0 g/cm³ for SK1BL (8 wt% D.V.B.) and 25.0 g/cm³ for SK112 (12 wt% D.V.B.). The ion exchange equilibrium constant of histidine was 8.0 g/cm³ for SK1BL (8 wt% D.V.B.). Resin phase diffusivities of divalent amino acids are measured by batch uptake experiments. Resin phase diffusivities of divalent arginine were decreased from 9.0 × 10^?8 cm²/s to 1.6 × 10^?8 cm²/s while the D.V.B. content in resin increases from 4 wt% to 12 wt%. Resin phase diffusivity of histidine for 8 wt% D.V.B. resin was 7.0 × 10^?8 cm²/s. The steric hindrance model was able to describe measured resin phase diffusivities.     

离子交换法去除有机二胺吸收剂PA-A中的SO42-平衡及动力学研究

研究了大孔阴离子交换树脂对有机二胺吸收剂PA-A中SO42-的吸附相平衡和动力学行为。结果表明,D296型树脂对SO42-具有良好的吸附选择性,333K下的吸附容量可达100.20mg.g-1。Langmuir-Freundlich模型能较好地描述吸附交换行为。吸附过程符合Lagergren一级动力学模型。液膜扩散为吸附速率的主要控制步骤。     

HD—8大孔强酸性阳离子交换树脂的研制

本文介绍了一种能满足Ｌ－羟基氨酸离子层离新技术工艺要求的大孔强酸型阳离子交换树脂的研究开发情况。该树脂在生产中实际使用后表明，具有合适的吸附洗脱中各组分分离安全，洗脱液浓集集中，Ｌ－羟基脯胺酸收率高，质量达到并超过规定指标。     

铵型阳离子树脂吸附L-左卡尼汀

通过研究pH变化对L-左卡尼汀在铵型磺酸基阳离子树脂上吸附过程的影响,确定相关工艺条件和参数。     

732型阳离子交换树脂吸附L-色氨酸的性能研究

在线跟踪观察732型阳离子树脂吸附L-色氨酸的行为。实验结果表明,732型阳离子树脂吸附L-色氨酸速率由液膜扩散控制,表观吸附速率常数,随温度的升高而增大,其表观活化能Ea为30．46kJ／mol;表观吸附速率常数随体系中葡萄糖含量的增大而减小;外加氯化钠导致两种竞争,低浓度有利于树脂对L-色氨酸的吸附。     

阴离子交换树脂吸附辣椒碱的动力学研究

以辣椒树脂为原料,采用静态吸附法确定了201×7型阴离子交换树脂吸附辣椒碱的最优工艺和提取机理。通过可见分光光度法测定了辣椒碱的质量浓度,并绘制出了不同pH的吸附等温线,建立了离子交换吸附辣椒碱的动力学模型。实验结果表明:该树脂吸附辣椒碱的最优pH值为5.5,当pH5.0或pH6.0时,Langmuir方程能够更好地拟合该吸附过程;而当pH=5.0~6.0时,辣椒碱的吸附等温线更符合Freundlich方程。在pH=5.5、308.15K下,较高的辣椒树脂的质量浓度能显著提高离子交换速率,且初期(t30 min)800~1200r/min的搅拌速率有利于吸附过程。通过计算得出,树脂吸附辣椒碱模型的速率常数k0=2.11×10-3s-1、活化能Ea=12.6 k J/mol、反应级数为0.268,并利用Freundlich模型解析获得了最优pH值(5.5)下阴离子交换树脂吸附辣椒碱的动力学方程。     

阳离子交换树脂催化合成异丁酸正丁酯

以异丁酸和正丁醇为原料,阳离子交换树脂(NKC-9)为催化剂,合成了异丁酸正丁酯。考察了醇酸摩尔比、催化剂用量、反应时间等因素对反应的影响,并测定了动力学数据。通过实验得到了较佳制备工艺条件:n(正丁醇)∶n(异丁酸)=1.4∶1,NKC-9催化剂用量为异丁酸和正丁醇总质量的4%,反应温度≤125℃,反应时间2.0h,在该条件下,异丁酸的转化率达97.6%,催化剂重复使用5次后,异丁酸的转化率为96.4%。并建立了该酯化反应的表观动力学模型。     

Ion‐Exchange Equilibria of Nitrates on a Strongly Basic Resin

Adsorption isotherms of nitrates on the resin Amberlite IRA 410 at various pH values (6.8–12) were experimentally determined by batch tests. Six models involving two or three parameters are discussed. Concerning the Langmuir equation, the linear method had no significant effect on the estimation of isotherm parameters and simulation precision. Irrespective of the pH, the Sips model was found to give the best fit of the adsorption isotherm data. The maximum adsorption capacity decreased with increasing pH values and could be predicted by the correlation equations obtained in this study.     

732离子交换树脂从胱氨酸母液提取L-精氨酸的研究

实验考察了温度、pH值、氯化铵和氯化钠浓度对 732阳离子交换树脂吸附L -精氨酸的影响 ,并测定了 2 5℃时 732离子交换树脂吸附L -精氨酸的吸附等温线。结果表明 :温度变化对吸附率影响较小 ;pH值增大 ,吸附率下降 ;溶液中氯化铵或氯化钠浓度增大 ,吸附率迅速下降 ,且当氯化铵或氯化钠物质的量浓度达到1.0mol·L-1时 ,L -精氨酸难于被吸附 ;2 5℃时 ,最大饱和吸附量约为 117g·kg-1树脂。根据实验结果开发了从胱氨酸母液提取L -精氨酸的工艺 ,提取率达到 80 %以上。     

Esterification of Pentanoic Acid with 1-Propanol by Sulfonated Cation Exchange Resin: Experimental and Kinetic Studies

Liquid-phase esterification reaction of 1-propanol with pentanoic acid to give propyl pentanoate over Amberlyst 15 has been studied. The reaction carried out in a batch reactor was found to be independent of mass transfer effects in the temperature range of 323.15–363.15 K. The reaction is highly temperature sensitive. Increase in 1-propanol concentration has an enhancing effect on the conversion, whereas water acts as an inhibitor. As alcohol–acid mixtures behave nonideally, kinetic analysis has been performed using UNIFAC liquid-phase activities of pentanoic acid, 1-propanol, propyl ester, and water. Observed kinetics is best represented by Eley–Rideal mechanism. Surface reaction was observed to be a rate-limiting step.     

Kinetics and Equilibrium Studies for the Removal of Cobalt,Manganese, and Silver in Ethanol using Dowex 50W-x8 Cation Exchange Resin

Organic solvents such as ethanol, find a wide range of applications in fuel, pharmaceutical industries, food industries, and paint formulations, among others. The removal of Ag(I), Co(II), and Mn(II) ions in ethanol by cation exchange resin, Dowex 50W-x8, was investigated. The adsorption characteristics of metal ions onto Dowex 50W-x8 resin were described by Langmuir isotherms. The maximum sorption exchange capacities at 298 K were obtained as 47.4 mg g^?1, 52.6 mg g^?1, and 58.5 mg g^?1 for Ag(I), Co(II), and Mn(II), respectively. The data was also fitted to Temkin and Dubinin-Radushkevich adsorption isotherm models to evaluate other adsorption properties. The ion exchange of silver, cobalt, and manganese on cation exchange resin followed pseudo-second-order kinetics, and the intraparticle diffusion was rate-determining step. The thermodynamic parameters indicated that the sorption of metal ions onto Dowex 50W-x8 resin was spontaneous (negative ΔG°) and endothermic in nature (positive ΔH°) implying that the adsorption capacity increased with increasing temperature. The resin can be regenerated by eluting metal ions with 3.0 mol L^?1 HNO₃ followed by washing it with 10 mL of Millipore water and 10 mL of 2.0 M NaOH, respectively. The proposed method was applied for metal ion removal in real ethanol samples.     

Loading Effects and Adsorption Isotherms for Single and Dual Chiral Systems Applying Ligand Exchange Chromatography

The adsorption behavior of five amino acid racemic mixtures applying ligand exchange chromatography for their enantioselelctive separation under the simultaneous interaction of two chiral selectors was investigated. Single and dual chiral systems consisting of a commercially available non-chiral column and a commercially available chiral column using a chiral mobile phase were applied. The adsorption isotherms for three amino acids were determined for both systems only in the linear range due to displacement effects. Additional loading effects investigations reveal decrease of the capacity factors when applying the single chiral system (no base line separation) compared to the dual one. Furthermore, the selectivity for the dual system was always higher than one.     

超声波对苯酚在NKAⅡ树脂上吸附平衡的影响

本文以苯酚水溶液／NKAⅡ树脂吸附体系为实验对象,研究超声波对液固吸附平衡的影响。分别测定了在超声场和无超声场条件下,苯酚在NKAⅡ树脂上的吸附等温线,报道了在超声场条件下苯酚在高聚物吸附剂上的吸附等温线。研究结果表明：超声场作用下的吸附平衡等温线要低于在常规条件下的吸附等温线,超声场强度越大,苯酚在吸附剂上的吸附容量就越小。向吸附体系施加超声场,会导致吸附体系的温度升高。超声场对吸附平衡的影响是由超声场的热效应和非热效应所引起的,而后者的影响要大于前者。向液固吸附体系添加乙醇或乙酸乙酯作为第三组分,能进一步使体系的相平衡关系朝着吸附量减少的方向移动,这种变化在超声波场条件下更为明显。     

非缓冲体系中性氨基酸的离子交换平衡

研究了非缓冲体系中性氨基酸在７３２型强酸性阳离子交换树脂上的离子交换平衡，并提出了平衡模型。该理论模型考虑了氨基酸的两性弱解离性质和树脂能团的能量非均一性，可以很好地关联氨基酸与Ｈ＾＋的二元离子交换平衡，并且通过两个二元体系ＶＡＬ／Ｈ＾＋和Ｎａ＾＋／Ｈ＾＋的平衡参数成功地预测了三元体系ＶＡＬ／Ｎａ＾＋／Ｈ＾＋的平衡关系，表明该模型可以描述非缓冲体系中性氨基酸的多元离子交换平衡。     

CO2在全氟羧酸离子交换膜内促进传质特性的研究

本文以全氟羧酸离子交换膜为支撑体、乙二胺(EDA)为活性络合剂、制备促进传质膜。在常用的工业条件下,测定了纯CO_2以及CO_2/N_2二元混合物在该膜内的渗透通量。实测结果表明,此膜对CO_2的促进因子可达13.8,而对CO_2/N_2的分离因子高达316。本文假设促进传质过程的控制步骤为气体在膜相的扩散,据此导出了相应的机理模型,该模型与实测结果吻合良好。     

负载Al离子交换树脂固体催化剂的制备与应用研究

研究制备了负载Al的离子交换树脂催化剂,并对制备条件进行讨论,得到了较好的制备工艺为AlCl3与树脂的配比为8%,溶剂无水乙醇用量为80 mL,78.3℃回流反应8 h,最终铝含量为1.44 g/100 g树脂。通过红外光谱对其进行表征,结果表明732树脂在1020 cm-1处的吸收峰发生明显裂分,形成1011 cm-1和1025 cm-1两个吸收峰,说明732树脂磺酸基与AlCl3发生了络合反应,同时将其应用于丁烯二酸糠醇甲酯合成反应中取得了良好的催化效果。     

用DSC法研究聚苯乙烯磺酸钠阳离子交换树脂热分解反应的非等温动力学

用DSC法研究了粉状聚苯乙烯磺酸钠阳离子交换树脂受热反应的非等温动力学。在温度区间为390~500℃,先发生一个放热反应,其后是吸热反应。测定了这两个表观受热反应的动力学基础数据-表观活化能和频率因子分别为:(2.8±0.4)×102kJ/mol,278±17 kJ/mol和(2.4±0.4)×1020/min,(5.2±0.4)×1019/min(99%置信度)。还测定了上述两个表观反应的反应热,前者为-8±3 J/g,后者为77±8 J/g(390℃时无水树脂重)(95%置信度)。     

Batch and Column Adsorption of Cu(II) on Unmodified and Oxidized Coir

Abstract

The potential of coir, a low cost lignocellulosic material, was assessed for the removal of Cu(II) ion from aqueous solutions of copper sulphate. The coir fiber was also modified by an oxidative treatment, whereby the maximum uptake of Cu(II) increased to 6.99 mg/g as compared to 2.54 mg/g for the unmodified coir. A Langmuir type of adsorption was followed by oxidized coir fiber. A second order rate equation was observed for the Cu(II) uptake. The lowering of pH adversely affects adsorption on both the materials. Almost complete desorption of the loaded Cu(II) was possible using 0.25 N hydrochloric acid. The materials retained the adsorptive capacity up to three cycles when an intermediate regeneration step was given with dilute sodium hydroxide solution. In a fixed column packed with oxidized coir fibers, it was observed that the breakthrough time decreased with an increase in inlet Cu(II) concentration. The desorption level in the fixed bed column was around 90% and the column was regenerated and used up to eight cycles. The fixed bed column packed with oxidized coir was used to remove Cu(II) from an electrochemical industrial effluent. An ion exchange mechanism has been proposed for uptake of Cu(II) on the oxidized coir fiber.     

L-组氨酸与L-赖氨酸在732阳离子交换树脂上分离系数的测定

文章测定了L-组氨酸与L-赖氨酸在732阳离子交换树脂上吸附动力学曲线,考察了不同操作条件对两种氨基酸分离系数的影响,结果表明:L-组氨酸与L-赖氨酸在树脂上吸附平衡时间为15 min;当pH大于5时,分离系数急剧升高,但L-组氨酸吸附率急剧下降,溶液适宜的pH为5～6之间;增大初始浓度有利于分离系数的提高;NH4+存在对分离系数影响较大,应在吸附前除去大部分的NH4+。     

高温高压浆态鼓泡床反应器中的气-液传质

The gas-liquid mass transfer of H2 and CO in a high temperature and high-pressure three-phase slurry bubble column reactor is studied. The gas-liquid volumetric mass transfer coefficients kLa are obtained by measuring the dissolution rate of H2 and CO. The influences of the main operation conditions, such as temperature, pressure,superficial gas velocity and solid concentration, are studied systematically. Two empirical correlations are proposed to predict kLa values for H2 and CO in liquid paraffln/solid particles slurry bubble column reactors.