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.

Study on the influence of humic acid of different molecular weight on basic ion exchange resin's adsorption capacity

在这篇论文，腐殖的酸(哈) 是进不同分子的重量节的 ultra-filtered 并且被多元素分析，紫外 254/TOC, 英尺红外和三维的荧光描绘度谱。因为不同分子的重量的腐殖的酸有不同吸水、分子的尺寸，基本离子交换树脂的最大的吸附能力在其分子的重量从 6000 ～ 10,000 Da 的腐殖的酸上出现。

Purification of Lactic Acid by Heterogeneous Catalytic Distillation Using Ion-exchange Resins

The purification of lactic acid based on the esterification of raw lactic acid from fermentation broth and then the catalytic distillation hydrolysis of methyl lactate simultaneously to achieve pure lactic acid is reported. The esterification kinetics of lactic acid with methanol catalyzed by strong-acid cation-exchange resins (Amberlyst-15,D001, D002, NKC, 002) was studied under the condition that simulates the real catalytic environment. Experimental results were correlated by a Langmuir-Hinselwood model and the nonideality of the solution was taken into account by using activities calculated by the universal quasichemical functional group activity coefficient (UNIFAC) method.A good agreement between the model and the experimental data was achieved. Continuous purification experiments were conducted to find the optimum column configuration and operation condition for the system. The effects of various parameters, e.g. the length of different section of the column, feed rate and ratio of reactants, packing material and catalyst type, were studied. This novel system shows good separation results in lab scale, and is potential for industrial application.

Kinetic Study of Esterification of Lactic Acid with Isobutanol and n-Butanol Catalyzed by Ion-exchange Resins

The esterification reactions of lactic acid with isobutanol and n-butanol have been studied in the presence of acid ion-exchange resin Weblyst D009.The influences of catalyst loading,stirrer speed,catalyst particle size,initial reactant molar ratio and temperature on the reaction rate have been examined.Experimental kinetic data were correlated by using the Pseudo-homogeneous,Langmuir-Hinshelwood and Eley-Rideal models.Nonideality of the liquid phase was taken into account by using activities instead of molar fractions.The activity coefficients were calculated according to the group contribution method UNIFAC.Provided that the nonideality of the liquid is taken into account,the esterification kinetics of lactic acid with isobutanol and n-butanol catalyzed by the acid ion-exchange resin can be described using all three models with reasonable errors.

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.

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.

酸性矿山废水中多种有价金属的高效分离

酸性矿山废水(AMD)中多种有价金属的高效分离回收,是重金属减排和资源化利用的关键。文章通过中和沉淀实验和静态吸附实验探究回收有价金属的最佳沉淀和吸附pH,成功开发了中和沉淀—离子交换—中和沉淀组合工艺,并应用于大宝山AMD的处理。结果表明,AMD在pH为3.00和9.80中和沉淀时,分别沉获64%的Fe_(2)O_(3)富铁渣和51%的Mn O富锰渣。采用离子交换树脂分别在pH 3.95和6.10条件下对AMD中的Cu和Zn进行吸附,得到质量浓度为Cu^(2+)11~26 g/L,Zn^(2+)10~20 g/L的两种解吸液。通过该组合工艺,AMD中的各金属Fe、Cu、Zn和Mn的回收率分别为:96%、81%、70%和60%,实现了有价金属的高效分离回收。若采用此工艺回收大宝山2000 m^(3)/d的AMD中的铜、锌、锰硫酸盐,每年的利润为119万元,经济效益非常显著。此处理工艺为酸性矿山废水的高效资源化利用提供了新路径。

增强型离子交换树脂催化醚化汽油TAME的合成

在高压釜式反应器中,以甲醇和异戊烯为原料,增强型离子交换树脂Amberlyst为催化剂,制备了高辛烷值醚化汽油组分TAME。改变反应温度、催化剂用量等单一实验变量,探索得到了最佳工艺条件:反应温度70℃,催化剂用量为20%,醇/烯比为2。在最优条件下,该催化反应只需进行4.5h,TAME的摩尔产率就达到70%。

The Synthesis of Cyclic Amino Acids

Several cyclic amino acids (1-4) were synthesized from glycine. Isocyanate ester was prepared as the key intermediate and reacted with dibromoalkanes to afford the target compounds.

Removal of Copper from Acid Mine Drainage (AMD) or Acid Rock Drainage (ARD)

Acid mine drainage is wastewater from a mine having a low pH and an elevated level of dissolved heavy metals. These metals are harmful to aquatic, animal and human life. This paper looks at the removal of copper from acid mine drainage using ion exchange to less than 1 mg/l. A weak acidic cation resin was used. Spectrophotometric determination of copper with sodium diethyldithiocarbamate was used to determine the copper concentrations in the treated water. Using regression analysis, the experimental results gave a correlation coefficient of 0.977 and a coefficient of determination of 99.5%. Results indicated that the higher the flows rate the shorter the period after which the copper concentration in the treated water reaches 1 mg/l. At pH 3.85 and 5.09, the resin performed better and at pH above 6.62 and between pH 3.0 and below the resin’s does not perform well. The higher the resin height the greater is the resin exchange capacity and the longer it takes for the copper concentration to reach 1 mg/l in the treated water. The higher the wastewater copper concentration the shorter the time it takes the resin to reach 1 mg/l. The results for this experiment indicated that acid mine drainage can be treated well by ion exchange resins, but it is also very important to establish suitable operating conditions.

PURIFICATION OF L-METHIONINE AND N-ACETYL-D-METHIONINE FROM THE MIXTURE OF ENZYMATICALLY DEACYLATED N-ACETYL-DL-METHIONINE

N-acetyl-D-methionine, NaAc and the remains of N-acetyl-L-methionine dramatically affect the purification of L-methionine when purified from the mixture of enzymatically deacylated N-acetyl-DL-methionine, leading to a low yield conventionally. Here, this paper reports a successful separation and purification of both L-methionine and N-acetyl-D-methionine by an H ion-exchange column. The pH, L-Met concentration and the ratio between the content of sodium cation and the ion-exchange capacity were optimized to obtain the maximum yield. Experimental results indicate that, under the optimized conditions, the yields of L-methionine and N-acetyl-D-methionine can reach as high as 85% and 75%, respectively.

基于载铀树脂饱和再吸附-淋洗一体化工艺的U型塔设计研究

针对部分酸法地浸铀矿工艺在浸出中后期存在的浸出液铀浓度偏低、HSO_(4)^(-)离子竞争吸附、吸附饱和树脂容量低、固定床淋洗合格液铀浓度低等问题,设计了一种离子交换设备U型塔,研究了采用饱和再吸附与淋洗一体化工艺处理载铀树脂,考察了处理后淋洗液中铀浓度的变化。结果表明:经U型塔一体化工艺处理后,淋洗合格液中铀质量浓度升至43~50 g/L;U型塔运行稳定,树脂运移顺畅,塔内铀浓度梯度分布合理。该设备适用于地浸采铀浸出液处理过程,有一定的推广应用价值。

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。

酸盐分离技术在镍电积阳极液中的应用

目前酸盐分离技术主要有树脂吸附法、离子交换法和膜分离技术三大类,但将其应用于镍湿法冶炼中镍电积阳极液的报道较少。总结了三大类酸盐分离技术的原理和应用,并分别采用树脂吸附法、扩散渗析法、特种纳滤膜和电渗析结合的方法对镍电积阳极液进行酸盐分离试验。结果表明,三种方法对镍电积阳极液均有一定的分离效果,其中树脂吸附法易饱和,需反洗再生,造成体积膨胀;扩散渗析法对硫酸的回收率在80%以上,镍的截留率在90%以上,但回收的硫酸浓度较低,同样存在体积膨胀问题;特种纳滤膜和电渗析结合法对镍离子的截留率可达90%以上,氢离子去除率可达70%以上,同时浓缩后的氢离子浓度可提高400%以上,镍离子浓度可提高500%以上,淡化液中各种离子浓度小于50 mg/L,可用作纯水,并且该方法不会造成系统体积膨胀,具有工业化应用价值。

离子交换树脂回收酸性溶液中钨的试验研究

白钨矿酸浸过程钨以钨同多酸形式产出,此分解方法为白钨矿冶炼提供了新的途径,但后续从钨同多酸浸出液中回收钨是关键。本文比较了不同阴离子交换树脂对钨同多酸溶液的吸附行为,确定大孔弱碱性阴离子交换树脂D301为最佳树脂。主要考察了D301树脂用量、溶液pH值、吸附温度、钨浓度和吸附时间对树脂吸附钨的影响。结果表明,在树脂用量为5倍理论量,溶液pH值为2~3,吸附温度为40℃,钨(WO_(3))浓度为50~100g/L,吸附时间为240min的条件下,D301树脂对钨同多酸溶液中的钨吸附率达99.4%以上。同时,研究了载钨树脂的解吸行为,结果表明,对D301载钨树脂解吸效果最好的解吸剂种类为NaOH溶液,在NaOH溶液用量20mL、浓度4mol/L以及解吸温度50℃、时间60min的条件下,钨的解吸率可达97.94%。

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%。

可见光-过一硫酸盐-磁性离子交换树脂协同工艺去除水中腐植酸的效能与机理

文中研究了可见光(VI)-过一硫酸盐(PMS)-磁性离子交换(MIEX)树脂体系协同处理水中腐植酸(HA)的效能、活性氧化物质(ROS)种类及活化机理、HA的去除机理以及影响HA去除的因素。结果表明,该体系对水中HA有较好的去除效果,反应90 min后,HA的去除率达到52.9%,显示了三者的协同促进作用。树脂母体中的铁氧化物协同VI,可有效活化PMS,产生硫酸根自由基和羟基自由基等活性物质。HA的去除主要是ROS氧化HA强化MIEX树脂的吸附作用,而非自由基的矿化降解。MIEX树脂投加量以及PMS浓度的增加可促进HA的去除,而温度在298 K以上时,影响不明显。该体系在有效去除水中HA的同时,可有效去除反应过程中的副产物SO_(4)^(2-),显示了良好的应用前景。

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。