Adsorption behavior and mechanism of cadmium on strong-acid cation exchange resin

The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.

USE OF CATION EXCHANGE RESIN IN SYNTHESIS OF N-SUBSTITUTED-1-AMINOALKANEPHOSPHONATE AND-PHOSPHINIC ACIDS

Strongly acidic cation exchange resin(1x1,H form)has been successfully used as a catalyst in synthesis of diphenyl N-benzyloxycarbonyl-1-aminobenzylphosphonate, N-benzyloxycarbonyl-1-aminobenzylphenylphosphinic acid and N-p-tolylsulfonyl-1-aminobenzyl phenylphosphinic acid in high yields.

Elution Behaviour of Monocarboxylic Acids on a Cation-exchange Resin Column

The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.

Mechanism and kinetics study on removal of Iron from phosphoric acid by cation exchange resin

Iron element is one of the main impurities in wet-process phosphoric acid and it has a significant impact on the subsequent phosphorus chemical products. This paper studied the feasibility of using Sinco-430 cation exchange resin for iron removal from phosphoric acid. The specific surface area and the total exchange capacity of resin were 8.91 m2·g-1 and 5.18 mmol·g-1, respectively. The sorption mechanism was determined by FTIR and XPS and the results indicated that iron was combined with-SO3 H in resin. The removal process was studied as a function of temperature, H3 PO4 content and mass ratio between resin and solution. The unit mass of resin to remove iron was 0.058 g·g-1 resin when the operating parameters were T = 50 ℃, H3 PO4 content = 27.61 wt%and S/L = 0.1, respectively. Kinetics study demonstrated that pseudo-second-order reaction model fits this study best and the calculated activation energy of overall reaction is 29.10 kJ·mol-1. The overall reaction process was mainly controlled by pore diffusion.

Adsorption equilibrium, kinetics, and dynamic separation of Ca2+ and Mg2+ ions from phosphoric acid–nitric acid aqueous solution by strong acid cation resin

The separation of Ca2+and Mg2+ions from phosphoric acid-nitric acid aqueous solution is very significant for the neutralization process of nitrophosphate fertilizer.This paper studied the adsorption equilibrium,kinetics,and dynamic separation of Ca2+and Mg2+ions by strong acid cation resin,and the effects of phosphoric acid and nitric acid on the adsorption process were investigated.The results reveal that the adsorption process of Ca2+and Mg2+ions in pure water on resin is in good agreement with the Langmuir isotherm model and their maximal adsorption capacities are 1.86 mmol·g-1 and 1.83 mmol·g-1,respectively.The adsorption kinetics of Ca2+and Mg2+ions on resin fits better with the pseudo-first-order model,and the adsorption equilibrium in pure water is reached within 10 min contact time,while at the present of phosphoric acid,the adsorption rate of Ca2+and Mg2+ions on resin will go down.The dynamic separation experiments demonstrate that the designed column adsorption is able to undertake the separation of metal ions from the mix acids aqueous solution,but the dynamic operation should control the flow rate of mix acid solution.Besides nitric acid solution was proved to be effective to completely regenerate the spent resin and achieve the recyclable operation of separation process.

Removal of Co(Ⅱ) from aqueous solutions by NKC-9 strong acid resin

A strong acidic ion exchange resin(NKC-9)was used as a new adsorbent material for the removal of Co(Ⅱ)from aqueous solutions.The adsorption isotherm follows the Langmuir model.The maximum adsorption capacity of the resin for Co(Ⅱ)is evaluated to be 361.0 mg/g by the Langmuir model.It is found that 0.5 mol/L HCl solution provides effectiveness of the desorption of Co(Ⅱ)from the resin.The adsorption rate constants determined at 288,298 and 308 K are 7.12×10-5,8.51×10-5and 9.85×10-5s-1, respectively.The apparent activation energy(Ea)is 12.0 kJ/mol and the adsorption parameters of thermodynamic are-H Θ=16.1 kJ/mol,-SΘ=163.4 J/(mol·K),-G Θ 298 K=-32.6 kJ/mol,respectively.The adsorption of Co(Ⅱ)on the resin is found to be endothermic in nature.Column experiments show that it is possible to remove Co(Ⅱ)ions from aqueous medium dynamically by NKC-9 resin.

3种离子交换材料吸附L-精氨酸的研究

测定了 2 5℃时 732强酸型离子交换树脂、D0 0 1大孔强酸型离子交换树脂和羧酸型阳离子交换纤维 3种离子交换剂吸附L 精氨酸的吸附动力学曲线和吸附等温线 ,结果表明 ,三者达到吸附平衡的时间分别为 732树脂 2h、D0 0 1树脂 4 0min、羧酸型离子交换纤维 30min ,三者的最大平衡吸附量分别为 117、137和 91g/kg ;考察了 pH值、氯化钠和氯化铵浓度对 3种离子交换剂吸附 L 精氨酸的影响 ,结果表明吸附的适宜 pH均在 7～ 8之间 ,氯化钠和氯化铵的存在均导致三者吸附L 精氨酸的吸附率迅速下降。

大孔强酸型阳离子交换树脂对L-精氨酸的吸附

考察了D001大孔强酸型阳离子交换树脂对L?精氨酸的吸附.测定了25oC下的吸附等温线,发现用Langmuir方程和Freundlich方程可以较好地描述L?精氨酸在该树脂上的吸附;D001树脂吸附L?精氨酸约30min即可达到平衡;氯化铵或氯化钠的存在使吸附率明显下降;pH对吸附影响明显,从胱氨酸母液中吸附L?精氨酸的适宜pH为7～8;同时测定了胱氨酸母液吸附的动态吸附穿透曲线和洗脱曲线,穿透曲线较缓而洗脱峰较集中.

聚乙烯-对苯乙烯磺酸钠接枝膜制备

采用γ射线引发共辐照接枝方法，研究了丙烯酸（ＡＡ）及对苯乙烯磺酸钠（ＳＳＳ）双元混合体系对聚乙烯（ＰＥ）薄膜的接枝规律性，用一步法直接制备了聚乙烯强酸型阳离子交换膜。研究结果表明，在辐照接枝过程中， ＡＡ首先与聚乙烯反应；改善了薄膜表面的亲水性，然后 ＳＳＳ与 ＰＥ接枝共聚。通过 ＳＳＳ单一体系及双元混合体系的研究，发现 ＡＡ的存在是实现 ＰＥ 磺化的必要条件。本文系统研究了影响共接枝反应的辐照剂量、阻聚剂用量、单体摩尔比及总摩尔浓度变化等因素。并做了接枝物的ＩＲ分析及物理电化学性能测试。

响应面法优化合成1,1,1,3,5,5,5-七甲基三硅氧烷

选用六甲基二硅氧烷(MM)和高含氢硅油(DH)为原料,强酸型离子交换树脂作催化剂,采用响应面优化法对1,1,1,3,5,5,5-七甲基三硅氧烷(MDHM)的合成工艺进行优化。在单因素实验的基础上,依次采用Plackett-Burman设计,最陡爬坡实验及Box-Behnken设计法进行工艺优化,以MDHM的质量分数为响应值作响应面,然后进行回归分析。实验结果表明,MDHM的最佳合成条件为:反应物质量比为m(DH)∶m(MM)=1∶13.45,反应温度为62.5℃,催化剂用量为7.09%。在反应时间10h的条件下,产物中MDHM的质量分数为40.62%,与模型预测值基本相符。通过研究温度对反应动力学的影响,进一步验证了所取温度和时间的合理性。

强酸性阳离子交换纤维富集-电感耦合等离子体原子发射光谱法测定水系沉积物中稀土元素

对聚丙烯基强酸性阳离子交换纤维分离富集痕量稀土元素La，Nd，Eu，Gd，Er和Yb及其电感耦合等离子体原子发射光谱（ICP-AES）测定进行了研究。优化了纤维柱吸附和洗脱稀土元素的条件，pH3的稀土待富集试液以6-14mL／min流速上柱，以流速为1．5-4．0mL／min的10mL 2．5mol／L HNO3洗脱后，用ICP-AES测定。在洗脱前用0.5mol／L HNO3预淋洗，可将大部分K，Na，Mg，Ca，Ba，Cu，Zn，Fe和A1等共存元素除去，而不影响稀土元素的回收率。分析方法的检出限为La 0.016ng／mL，Nd 0．051ng／mL，Eu 0．006ng／mL，Gd 0．029ng／mL，Er 0．048ng／mL，Yb 0．006ng／mL。富集和测定了单纯水样和合成水样中的La，Nd，Eu，Gd，Er和Yb等稀土元素，它们的回收率为88．0％-110％，相对标准偏差为0．3％-2．7％；富集和测定了水系沉积物国家标准物质（GBW07311）中这6种稀土元素，结果与认定值吻合，相对标准偏差为1．1％-5．2％。

NKC-9干氢型树脂催化合成油酸甲酯

采用强酸性阳离子交换树脂作催化剂,对油酸和甲醇反应合成油酸甲酯的工艺进行研究。分别筛选了4种型号的树脂,其中以NKC-9干氢型树脂催化效果最好。考察了酸醇摩尔比、反应温度、催化剂用量、脱水剂用量、反应时间和催化剂重复使用性等因素对转化率的影响。结果表明:反应的适宜条件为酸醇摩尔比1∶2,反应温度70℃,催化剂用量为油酸质量的50%,脱水剂无水CaCl2用量为催化剂用量的10%,反应时间2 h。在此条件下,转化率可达93.85%。催化剂重复使用6次后转换率仍保持在90%以上。研究显示,采用NKC-9干氢型树脂催化合成油酸甲酯具有良好的工业应用潜力。

强酸阳离子交换纤维柱分离-石墨炉原子吸收光谱法测定金属铟及其盐中镉

研究表明,当In的共存量大于或等于400倍Cd量时,石墨炉原子吸收光谱（GFAAS）法直接测定Cd的误差≥＋5%。采用强酸阳离子交换纤维柱,控制试液流速为0.6 mL/min进行交换,用相同流速的1.2 mol/L HNO3淋洗交换柱,Cd从纤维柱上首先被洗脱而使之与In达到分离,有效地消除了In对Cd的测定干扰。In与Cd质量比（mIn∶mCd）在100∶1~1 000 000∶1之间,经过纤维柱分离,GFAAS测定Cd的检出限（3S）为1.5×10-5μg/mL,线性范围为5.0×10-5~1.0×10-2μg/mL;加标回收率为98%~102%,RSD（n=6）为0.8%~1.5%。测定金属铟和硫酸铟中Cd的含量分别为17.6μg/g和1.86μg/g,加标平均回收率分别为100%和99%,RSD（n=6）分别为2.0%和2.3%。

阳离子交换树脂催化1-丁烯合成醋酸仲丁酯

以强酸性阳离子交换树脂为催化剂催化1-丁烯与醋酸合成醋酸仲丁酯。考察了原料烯酸配比、反应压力、反应时间、反应温度、催化剂用量等因素对醋酸转化率的影响,结果表明:在原料烯酸比为2.0∶1,反应压力5.5MPa,反应时间11h,反应温度120℃,催化剂用量为醋酸质量的10%的条件下,醋酸转化率为92.4%～95%。气相色谱-质谱分析表明,醋酸仲丁酯的选择性为92%。该催化剂对1-丁烯与醋酸的酯化反应有良好的催化活性和选择性,且催化剂稳定性良好。

pH和温度对亚微米强酸树脂吸附L-赖氨酸的影响

研究了溶液ｐＨ和温度对亚微米强酸树脂离子交换赖氨酸（＞３０ｇ／Ｌ）的影响，与７３２强酸树脂进行了对比，并对所得吸附等温线进行了关联，研讨其吸附模型。结果表明：ｐＨ对亚微米强酸树脂交换有明显影响，其吸附量远大于７３２树脂；温度对其影响不大，但引起了交换量极值点向ｐＨ值小的方向移动。氢型亚微米强酸树脂的吸附等温线呈现出超当量吸附和多分子层吸附两个特征，并符合ｄｅＢｏｅｒ－Ｚｗｉｋｋｅｒ公式，属极性吸附模型。

阳离子交换树脂和Al_2O_3催化葡萄糖制取5-羟甲基糠醛

以葡萄糖为原料、强酸性阳离子交换树脂732和Al2O3为催化剂、二甲基亚砜(DMSO)为反应介质,研究了5-羟甲基糠醛(5-HMF)的制备方法与反应过程,以及阳离子树脂732和Al2O3的重复使用性.结果表明,DMSO对葡萄糖转化为5-HMF的反应有促进作用,葡萄糖初始质量分数为10%时,130℃下反应12 h后,葡萄糖的转化率可达90.19%,5-HMF的得率可达44.53%,选择性可达49.37%.同时,文中研究结果显示,经过多次使用,阳离子树脂732和Al2O3的催化选择性依然保持稳定.

阳离子交换树脂富集、钪-钙-茜素红共显色分光光度法测定水中微量钪的研究

选用强酸型阳离子交换树脂在一定条件下分离富集水中的微量钪，以钪－钙－茜素红（Ｓｃ－Ｃａ－ＡＲＳ）异多核红色配合物显色反应、分光光度法测定。采用柠檬酸－抗坏血酸作掩蔽剂消除干扰。钪在０～０５ｍｇ／Ｌ范围内呈线性关系。该法应用于水中微量钪的测定，快速、准确、灵敏、简便、效果良好。

强酸性阳离子交换树脂催化2,4/2,5-二甲酚烷基化反应研究

采用烷基化方法,以NKC-9强酸性阳离子交换树脂为催化剂,将2,4/2,5-二甲酚分别转化成沸点差异较大的6-叔丁基-2,4-二甲酚和4-叔丁基-2,5-二甲酚,以便可以采用传统的精馏手段对烷基化产物进行分离。实验对离子交换树脂的催化条件、催化效率、选择性、使用寿命以及反应动力学进行了研究。结果表明,NKC-9离子交换树脂对2,4/2,5-二甲酚具有良好的催化活性和选择性,在最佳烷基化反应条件下的转化率达到91.1%,对6-叔丁基-2,4-二甲酚和4-叔丁基-2,5-二甲酚的选择性分别为98.5%和96.8%,而且具有反应条件温和及使用寿命长的特点。动力学研究结果表明,二甲酚浓度和异丁烯的分压对2,4-二甲酚烷基化反应速率的影响要小于2,5-二甲酚,催化剂加量影响相反。温度虽然对反应速率影响不显著,但提高温度更有利于增加2,4-二甲酚的烷基化反应速率。

有机溶剂中合成4,4＇-二氨基-1,1＇-联蒽醌-3,3＇-二磺酸

研究了在有机溶剂体系中催化溴氨酸进行Ullmann偶联反应合成4,4'-二氨基-1,1'-联蒽醌-3,3'-二磺酸(DAS)的工艺。有机溶剂可回收利用,大大减少了工业生产技术中含酸含盐废水的排放,并降低处理费用。考察了单一溶剂、不同组成和比例的混合溶剂对Ullmann偶联反应的影响,确定最优的溶剂体系为DMF:甲醇=1:2的混合溶剂;研究了最优溶剂体系下的反应时间、温度等因素的影响。对不同添加剂和铜粉粒径对反应的影响进行研究,阳离子交换树脂为最佳添加剂,23μm铜粉催化效果最优。所得DAS的含量最高为91.56%,收率最高为88.43%。

合成己二酸二甲酯的反应-精馏耦合技术

以732强酸性阳离子树脂为催化剂,己二酸和甲醇为原料采用反应精馏耦合工艺合成己二酸二甲酯。利用单因素法,以酯化率为指标,考察了醇酸物质的摩尔配比、反应时间、催化剂的用量和催化剂的置放位置对酯化反应的影响,得到了较佳的工艺条件:醇酸物质的摩尔配比为10,反应时间为3h,催化剂的用量为35g,催化剂的置放位置为反应精馏塔的上部。在该工艺条件下,酯化率可以达到85%。