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.

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.

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.

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.

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.

阳离子交换树脂分离-电感耦合等离子体发射光谱(ICP-OES)法测定盐湖卤水中偏硅酸含量

由于盐湖卤水中盐分浓度不同且盐度较高,采用常规分析方法很难准确测定。通过对阳离子交换树脂加入量、阳离子交换树脂交换时间、pH值对交换效率的影响、内标元素校正的考察,建立了阳离子交换树脂分离-电感耦合等离子体发射光谱法测定盐湖卤水中偏硅酸含量的方法。将盐湖卤水稀释5倍,加入6 g阳离子交换树脂,静态交换1.5 h,除去卤水中的大量阳离子后,选择Si 251.611 nm为分析谱线,以Y 371.030 nm谱线作为内标进行信号漂移校正,用电感耦合等离子体发射光谱仪能有效测定卤水中偏硅酸的含量。结果表明,校准曲线的线性范围为0.50~200 mg/L,所得回归方程的线性关系良好(r≥0.9994),检出限为0.16 mg/L,结果相对标准偏差(RSD,n=12)为1.8%~4.6%,加标回收率为96.3%~102%。同时采用紫外-可见分光光度法对偏硅酸含量进行方法比对,两种测试结果不存在显著性差异,表明所建立的方法具有良好的准确度。为提高盐湖资源的综合利用提供了可靠的数据支撑。

阳离子交换树脂催化合成新戊二醇过程研究

利用催化精馏技术,以2,2-二甲基-1,3-环氧丙烷为原料,强酸性阳离子交换树脂为催化剂,在催化精馏塔中进行催化水解反应合成新戊二醇,考察了温度、液空速、油水相比、催化剂的稳定性等因素对水解工艺结果的影响。采用N2吸附脱附、NH_(3)-TPD、FT-IR光谱、XPS光谱、TG、XRD、交换容量等表征手段对强酸性阳离子交换树脂的内部结构和元素价态进行分析,研究结果表明:强酸性阳离子交换树脂具有优异的催化性能,在温度为80℃,油水比(相比)为1∶4的条件下,新戊二醇的收率可达94.31%,连续运行200 h后,催化剂的稳定性能仍然良好,具有良好的工业应用前景。

DK-13和DK-3两种大孔弱酸阳离子树脂提取西索米星的吸附热力学和动力学研究

目的采用静态吸附实验考察了DK-13、DK-3两种大孔弱酸阳离子树脂对西索米星的吸附热力学和动力学行为。方法用刚果红分光光度法测定不同温度和不同初始浓度下的吸附等温线和吸附动力学、热力学曲线等。结果两种树脂对西索米星的吸附过程符合Langmuir吸附等温方程(R2>0.998)和拟二级动力学模型(R2>0.995);热力学参数计算结果显示,吉布斯自由能变ΔG、焓变ΔH、熵变ΔS均大于零,说明其吸附过程为非自发吸热的熵增过程。同时,研究还发现DK-13树脂交换带长度为DK-3的5.2倍,表明DK-13树脂适用于固定床而DK-3树脂用于连续离子交换床更有利。结论本研究结果为大孔弱酸阳离子树脂吸附提取西索米星工艺的工业化应用提供了理论指导。

电子用双环戊二烯苯酚树脂的绿色合成及表征

本文以双环戊二烯(DCPD)和苯酚为原料,以自制的新型强酸性阳离子交换树脂为烷基化反应的催化剂,催化苯酚与DCPD发生反应生成双环戊二烯苯酚树脂(DPR)。用阳离子交换树脂替代传统含氟催化剂作为烷基化反应的催化剂,减少了含氟废水的产生,更加绿色环保。通过改变反应时间、反应温度、原料配比、催化剂用量以及正交实验,探究烷基化反应的最佳工艺条件以及阳离子交换树脂磺化度对产物的影响,使合成的树脂能够符合电子用树脂的要求。同时探究DPR树脂的结构,并测定DPR树脂中不同聚合度组分的含量,以及DPR树脂的软化点、收率等数据。实验表明,当采用新型强酸性阳离子交换树脂为催化剂,反应条件为3 h、120℃,原料配比为4∶1,催化剂用量为20%时,聚合度为0的组分含量可达92.36%。

SCX-SPE结合UHPLC-Q-Exactive Orbitrap MS分析草乌中的四类二萜生物碱

目的对草乌中的二萜生物碱进行表征分析。方法以强酸性阳离子交换树脂固相萃取(SCX-SPE)分离纯化草乌中的二萜生物碱,并结合超高效液相色谱串联四极杆静电场轨道阱质谱(UHPLC-Q-Exactive Orbitrap MS)进行结构鉴定。结果结合精确分子质量、多级质谱裂解规律、对照品对比、Clog P值及文献报道,共从草乌中鉴定了99个二萜生物碱类成分,包括双酯型二萜生物碱(DDA)27个,单酯型二萜生物碱(MDA)29个,酰胺型二萜生物碱(ADA)40个,多酯型二萜生物碱(PDA)2个,以及长链型二萜生物碱(LDA)1个。结论本文所建立的SCX-SPE结合UHPLC-Q-Exactive Orbitrap MS方法能快速地鉴定草乌中的二萜生物碱类成分,可为草乌的药效物质基础及质量控制研究提供科学依据。

阳离子树脂催化乳酸与甲醇反应动力学

在酯化水解法提纯乳酸的生产过程中,酯化反应动力学的研究对该工艺具有非常重要的意义。以ZGC108酸性阳离子交换树脂为催化剂,在间歇釜搅拌釜式反应器中对乳酸和甲醇的酯化反应本征动力学进行研究。探究搅拌速率、催化剂用量、醇酸摩尔比、反应温度对反应过程的影响。得出最佳反应条件为转速500 r/min、催化质质量占反应液体总质量的3%、醇酸摩尔比3∶1、反应温度343.15 K。采用拟均相模型对实验数据进行关联,建立反应动力学模型。通过反应速率的验证,该模型合理地预测了动力学实验数据。

大孔树脂对增甘膦盐溶液Ca^(2+)去除性能研究

采用大孔阳离子交换树脂对增甘膦钙溶液进行脱钙处理,重点探讨了该树脂对Ca^(2+)的等温和动力学吸附行为,研究了pH对其吸附性能的影响及树脂的重复使用性,并对钙离子脱除机理进行了研究。结果表明:该树脂对Ca^(2+)的吸附不受溶液初始pH影响,在20 min内即可达到平衡,最大吸附量为52.87 mg/g,且经5次重复利用后,对Ca^(2+)的回收率仍可维持在98.2%以上;该过程符合Langmuir等温吸附模型、准二级动力学模型,另外,该树脂在处理实际增甘膦溶液时可实现钙离子的高效脱除;机理分析表明该树脂对Ca^(2+)吸附以离子交换反应为主。这为复杂有机废液中钙的分离脱除提供了有益的理论参考。

Cansolv废酸水再生阳离子交换树脂实验研究

Cansolv尾气氧化工艺运行过程中会产生较大量废酸水(含SO_(3)^(2-)、SO_(4)^(2-)),一般采用31%盐酸对生产废水装置阳离子交换树脂进行再生。为了研究Cansolv废酸水替代盐酸再生阳离子交换树脂效果,实验通过对001-7阳离子交换树脂进行静态及动态吸附、废酸水对吸附后树脂进行再生脱附,测定树脂吸附率(η%)及脱附率(P%)。实验结果表明,阳离子交换树脂对Ca^(2+)和Mg^(2+)均具有良好的吸附效果,废酸水作为脱附液进行树脂再生可行;动态吸附时阳离子交换树脂对Mg^(2+)和Ca^(2+)最大吸附率可达70%和50%,动态吸附最佳上柱流速为3 mL/min;废酸水作为洗脱液对2种离子均具有一定的洗脱能力,Mg^(2+)和Ca^(2+)的脱附率分别为81.9%和48.6%,且质量浓度为4%为洗脱液的最佳浓度。

海参酶解液中重金属铬的脱除

海参酶解液主要成分为海参多肽,海参多肽具有抗菌、抗病毒、抗肿瘤等活性,在多领域有着广阔的应用前景,但重金属污染是海参多肽应用过程中潜在的危害,对海参酶解液中的重金属脱除变得尤为重要。研究选用树脂法、壳聚糖及其衍生物法、络合法中的7种脱除材料对海参酶解液中的重金属铬进行脱除,结果表明,732型阳离子交换树脂、壳聚糖和植酸分别是3种脱除方法中的最佳脱除材料。经过正交试验与验证试验显示,732型阳离子交换树脂在实验条件为酶解液pH 6、脱除温度15℃、脱除剂添加量1 g、脱除时间2 h下,铬脱除率为(87±1.86)%,多肽保留率为(90±2.69)%,很好的脱除海参酶解液中的重金属铬,并能保留大部分多肽。该实验为高蛋白含量海洋动物酶解液中脱除重金属铬提供了参考。

强酸性阳离子交换树脂对铅的吸附行为及机理

通过静态吸附实验,研究了Pb2+在001×7强酸性阳离子交换树脂上的吸附行为,并从热力学和动力学方面对吸附过程进行了分析,用红外光谱的方法探讨了001×7树脂吸附Pb2+的机理。结果表明:在所研究的浓度范围内,Pb2+在001×7树脂上的吸附平衡数据符合Freundlich等温吸附方程,吸附为自发进行的放热过程;液膜扩散为Pb2+在001×7树脂上吸附速率的主要控制步骤,随着振荡频率的增加,吸附速率会逐渐增大;最佳的吸附pH在4左右,用3mol/L的硝酸对饱和树脂进行洗脱再生,洗脱率可达98%以上;298K温度下树脂的静态饱和吸附容量为414mg/g(湿树脂)。

甲醇和甲醛催化合成聚甲氧基二甲醚

聚甲氧基二甲醚作为柴油添加剂,可以提高柴油的十六烷值(CN),提高燃油的利用率,作为甲醇大宗下游产品具有广阔的应用前景。在固定床管式反应器中,以改性大孔阳离子交换树脂为催化剂,在温度40～100℃、液相空速1.32～16.37h-1、甲醛/甲醇摩尔比1～4和反应压力0.1～3.0MPa下,以单因素实验和正交实验相结合的方式,系统地研究了甲醛与甲醇缩醛化工艺条件,获得了较佳的工艺条件,在温度70℃、甲醛/甲醇摩尔比3∶1、液相空速1.32h-1、反应压力2.0MPa的条件下,甲醇的转化率为69.72%,DMM3—8选择性为62.08%。

采用大孔树脂与阳离子交换树脂分离纯化桑叶活性物质的效果分析

为了高效利用桑叶资源获取功能活性物质,在连续提取桑叶多糖、黄酮和生物碱的基础上,对3类活性物质进行分离纯化,研究大孔树脂和阳离子交换树脂对桑叶活性物质的吸附与洗脱性能。从3种大孔树脂中筛选的D101大孔树脂对桑叶多糖和黄酮具有较好的分离纯化效果:对桑叶多糖的最大吸附量达到308.42 mg/g,解吸率达70.18%,对桑叶多糖的脱色率和脱蛋白率分别达到89.29%、78.74%;对桑叶黄酮的最大吸附量达到38.11 mg/g,解吸率达81.46%。从2种阳离子交换树脂中筛选001*7阳离子交换树脂分离纯化桑叶生物碱,其最大吸附量达26.61 mg/g,解吸率达83.49%。分离纯化得到的桑叶多糖、黄酮和生物碱样品纯度分别为35.73%、38.64%、29.75%,表明联合使用D101大孔树脂和001*7阳离子交换树脂能有效地从桑叶提取物中分离纯化桑叶多糖、黄酮和生物碱3类活性物质。

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.

大孔弱酸阳离子交换树脂对Pb(Ⅱ)的静态吸附性能

通过静态吸附实验,研究了Pb2+在D152大孔弱酸阳离子交换树脂上的吸附行为,从热力学和动力学方面对吸附过程进行了分析,并通过红外光谱法探讨了吸附机理。结果表明,在所研究的条件范围内,Pb2+在D152树脂上的吸附为自发进行的吸热过程,符合Freundlich等温吸附方程;液膜扩散为吸附速率的主要控制步骤;在所研究的浓度范围内,333K温度下树脂的最大静态饱和吸附容量为214mg/g,298K温度下用3mol/L的硝酸作为解吸剂,解吸率可以达到98%;该树脂吸附操作简单,易再生,重复使用性良好,可望用于含铅废水的治理及铅的富集。