A state-of-the-art review on single drop study in liquid–liquid extraction:Experiments and simulations

The experimental and numerical investigations of single drop in liquid/liquid extraction system have been reviewed with particular focus on experimental techniques and computational fluid dynamic simulation approaches.Comprehensive surveys of available experimental techniques and numerical approaches for single drop rising and falling were given.Subsequently,single drop mass transfer was also reviewed both experimentally and numerically.Additionally,single drop breakage and coalescence process and the influencing factors were summarized and compared,so as to establish sub-models for population balance model.Future directions on single drop mass transfer,drop breakage and coalescence were suggested.It is believed that the single drop is a powerful tool to assist extraction process design from lab-scale to pilot-scale.

Experimental and Numerical Investigations of Single Drop Mass Transfer in Solvent Extraction Systems with Resistance in Both Phases

Numerical simulation of transient mass transfer to a single dropcontrolled by the internal resistance or by the resistance in bothphases was mathematically formulated and simulated in aboundary-fitted orthogonal coordinate system. The simulated resultson the transient mass transfer dominated by the internal resistanceare in good agreement with the Newman and Kronig-Brink models fordrops with low Reynolds number. When the drop Reynolds number is upto 200, the mass transfer coefficient from numerical simulation isvery low as compared with The Handlos-Baron model.

Extraction and stripping kinetics of copper(Ⅱ)by N902 using single drop technique

The kinetics of extraction and stripping of copper （Ⅱ） was investigated by the single drop technique with a new extractant N902 （a derivative of the salicylal-doxime） and the rate equations of extraction and stripping were derived, respectively. The apparent activation energies of extraction and stripping were estimated to be 20.14 kJ/mol and 30.0 k J/mol.

Terminal Effect of Drop Coalescence on Single Drop Mass Transfer Measurements and Its Minimization

For the mass transfer to single drops during the stage of steady buoyancy-driven motion, experimental measurement is complicated with the terminal effect of additional mass transfer during drop formation and coalescence at the drop collector. Analysis reveals that consistent operating conditions and experimental procedure are of critical significance for minimizing the terminal effect of drop coalescence on the accuracy of mass transfer measurements. The novel design of a totally-closed extraction column is proposed for this purpose, which guarantees that the volumetric rate of drop phase injection is exactly equal to that of withdrawal of drops. Tests in two extraction systems demonstrate that the experimental repeatability is improved greatly and the terminal effect of mass transfer during drop coalescence is brought well under control.

Kinetics of Forward Extraction of Boric Acid from Salt Lake Brine by2-Ethyl-1,3-hexanediol in Toluene Using Single Drop Technique

The kinetics of forward extraction of boric acid from salt lake brine by 2-ethyl-1,3-hexanediol in toluene was investigated using the single drop technique. The factors affecting the extraction rate include interfacial area between aqueous phase and organic phase, initial concentration of boric acid in aqueous phase, initial concentration of 2-ethyl-1,3-hexanediol in organic phase, and extraction temperature. The experimental results show that the extraction rate increases with the increase of the initial concentration of boric acid and2-ethyl-1,3-hexanediol, interfacial area of two phases, and temperature. With the temperature-dependence study, it is showed that the extraction is a diffusion-controlled process. The kinetic equation is presented for pH 1.0 in the aqueous phase and temperature of 318 K.

Kinetics of gadolinium extraction with D2EHPA and Cyanex301 using single drop column

The extraction kinetics of Gd（III） from the nitric acid medium using bis（2,4,4-trimethylpentyl） dithio- phosphinic acid （Cyanex301） and 2-ethylhexyl phosphoric acid （D2EHPA） in kerosene solution were measured by the single drop technique. The influences of hydrogen ion concentration, gadolinium ion concentration, extractant concentration, column height, and nozzle diameter on the extraction rate were investigated. The forward rate equations for the gadolinium extraction with D2EHPA and Cyanex301 were obtained. Based on the experimental results, the forward extraction rate constant was calculated. With the increase of D2EHPA or Cyanex301 concentration, the drop rising diameter and the value of interfacial tension decrease in the studied system, which shows that D2EHPA or Cyanex301 has interfacial activity as a kind of surfactant. Also, the droplet diameter and interfacial tension decrease with the increase of aqueous solution acidity. The experimental results show that the D2EHPA extractant provides faster extraction rate in comparison with Cyanex301 extractant, and it would be useful in industrial continuous extraction process.

Analysis of volatile compounds in Herba Asari by single-drop micro-extraction gas chromatography mass spectrometry

A rapid headspace single-drop micro-extraction（mix） gas chromatography mass spectrometry（SDMEGC -MS） for the analysis of the volatile compounds in Herba Asari was developed in this study.A mixed solvent of n-tridecane and butyl acetate（1：1） was finally used for the extraction at 70 C for 15 min with sample amount of 0.750 g and 100 mesh particle size.Under the determined conditions,the pound samples of Herba Asari were directly applied for the analysis.SDME-GC-MS,SPME-GC-MS and SD-GCMS methods were compared and the results showed that SDME-GC-MS method was a simple, inexpensive and effective way to measure the volatile compounds in Herba Asari and could be used for the analysis of volatile compounds in complex samples.

Extraction kinetics and kinetic separation of La(Ⅲ),Gd(Ⅲ),Ho(Ⅲ) and Lu(Ⅲ) from chloride medium by HEHEHP

Acco rding to the tetrad-effect,14 elements of lanthanides can be divided into four groups.In our previous study,a new approach was proposed for the kinetic separation of four rare earth ions La(Ⅲ),Gd(Ⅲ),Ho(Ⅲ) and Lu(Ⅲ) coming from four groups.In that study,four rare-earth ions were kinetically separated from their coexisting mixed aqueous solutions,by performing liquid-column elution using the aqueous solution containing four lanthanide rare-earth ions as the stationary phase and the dispersed organic oil droplets containing HEHEHP(2-ethyl hexyl phosphonic acid mono 2-ethyl hexyl ester) extractant as the mobile phase.The study of extraction kinetics is very important for understanding the kinetic separation of rare earth ions,which was carried out in this paper.The extraction kinetics of La(Ⅲ),Gd(Ⅲ),Ho(Ⅲ) and Lu(Ⅲ) by HEHEHP diluted in heptane were investigated using single drop method.The different parameters affecting the extraction rate such as column length,specific interfacial area,rare earth ion concentration,extractant concentration,hydrogen ion concentration and temperature were separately studied and the rate equations are deduced.It is first order with respect to rare earth ion and HEHEHP concentrations,and negative first order with respect to hydrogen ion concentrations.The rate constants at 293.15 K are 10-6.23,10-5.73,10-5.58 and 10-5.43,respectively.The experimental results demonstrate that the extraction rate of La(Ⅲ), Gd(Ⅲ),Ho(Ⅲ) or Lu(Ⅲ) is diffusion-controlled,and the extraction reaction takes place at the interface rather than in the bulk phase.The extraction model was proposed.Besides,the kinetic separation of rare earth ions by HEHEHP oil drops was discussed.

SDE-GC联用分析啤酒中N-亚硝胺

运用一滴溶剂萃取 气相色谱 (SDE GC)联用技术对啤酒中N 亚硝胺的分析进行了可行性探讨 ,讨论了一滴溶剂萃取的影响因素 ,优化了实验条件。该方法对挥发性亚硝胺检测线性范围在 5 0～ 70 0 μg L之间 ,检出限 :N 亚硝基二乙胺 (NDEA)为 1 0 μg L ,N 亚硝基吡咯烷 (NPYR)为 2 0 μg L ,N 亚硝基二丁胺(NDBA)为 5 μg L。回收率为 90 .9%～ 97.3% ,相对标准偏差为 6.1 %～ 7.9% ,一滴溶剂萃取所用的有机溶剂很少 ( 1～ 2 μL) ,环境污染小 ,萃取时间短 ,且回收率高。

异戊醇从氯化物-磷酸体系中萃取盐酸的动力学

采用上升液滴法研究异戊醇萃取盐酸的动力学,考察二相接触面积、水相中初始盐酸、磷酸浓度对盐酸萃取速率的影响,以比较磷酸和盐酸的萃取行为。实验结果表明,盐酸的初始正向萃取速率与二相界面积无关,随水相初始盐酸、磷酸浓度的增大而增大,异戊醇萃取盐酸可能属相内反应控制模式。水相中盐酸的存在促进磷酸的萃取,用较高浓度的工业盐酸分解开阳磷矿有利于湿法磷酸的分离和净化。经非线性最小二乘法回归实验数据,得出25℃时异戊醇萃取盐酸的动力学方程,其决定性指标为0.993 9,速率常数的相对标准偏差为7.69%。

SDE-GC-μECD分析蜂蜜中有机氯农药残留

采用一滴溶剂萃取-气相色谱-微池电子捕获检测器联用技术(SDE-GC-μECD)对蜂蜜中有机氯农药的分析进行了可行性探讨,研究了影响一滴溶剂萃取的相关因素,优化了分析条件.该方法除P,P'-DDD的线性范围在0.4～10ng/mL之间,其余的7种目标物(α-666,β-666,γ-666,δ-666,P,P'-DDE,O,P'-DDT,P,P'-DDT)线性范围均在0.1～10ng/mL之间,相关系数0.9974～0.9999,回收率范围为81.4%～93.9%,相对标准偏差2.4%～8.2%.与固相微萃取相比,SDE降低了对DDTS的检出限,而且还具有省钱省时、基体干扰小的优点.

SDE与SPME在分析水体中有机氯农药的对比

就水体中有机氯农药的分析对比了一滴溶剂萃取(SDE)与固相微萃取(SPME)两种预处理技术,并对影响SDE的因数(萃取溶剂、萃取时间、萃取温度和搅拌速度)进行了条件优化。结果表明,优化后的SDE不仅在相同的浓度范围内有更好的线性关系(相关系数为0.9976～0 9999),且增宽了β 666和P,P′ DDT的线性范围,降低了β 666、γ 666、δ 666和P,P′ DDT的检出限,用SDE GC μECD检测水体中有机氯农药残留方法是简单快速、经济廉价、准确可行。

7815单液滴法萃取锗的动力学研究

在稀硫酸的锗盐中,使用7815萃取锗,对萃取动力学进行了研究。试验结果表明,初始锗的萃取速度受有机相和水相的接触面积、硫酸浓度和水相中锗浓度的影响,锗的萃取受扩散步骤控制。试验建立的萃取动力学方程是Jf=2.3×10-9[Ge]0.91[H+]0.32,相对标准误差为3.98%。

SDE-GC-ECD分析水体中有机氯农药

运用单滴溶剂萃取气相色谱微池电子捕获检测器(SDE GC μECD)联用技术对水体中有机氯农药进行了分析,优化了影响单滴溶剂萃取的多种因素。该方法除了对p,p′DDD的线性范围在0.4~4 ng/mL之间外,其余的七种目标物(α666,β666,γ666,δ666,p,p′DDE,o,p′DDT,p,p′DDT)线性范围均在0.04~4.0 ng/mL 之间,相关系数为0.997 6~0.999 9,回收率范围为83.3%~96.1%,相对标准偏差为2.1%~7.8%。与传统的液液萃取相比,单滴溶剂萃取不仅准确度、精密度相当,而且还具有省时、省溶剂的优点。

液液微萃取技术在原子光谱分析中的应用进展

在复杂样品处理和痕量金属测定中,液液萃取是广泛采用的分离净化与富集技术。随着研究的深入和技术的发展,近年来出现了一些新型的微萃取技术。本文对原子光谱分析中比较常用的液液微萃取技术进行了评述,介绍了浊点萃取、单滴微萃取和分散液液萃取等新型绿色微萃取技术的基本原理和操作方法,列举了其在微量金属元素检测中的部分应用实例。同传统的萃取技术相比,液液微萃取用于痕量金属元素检测,操作简单、快速,有机溶剂用量少,对人体危害小,对环境污染小,同时又有极高的萃取效率和很大的富集倍数,具有更低的检出限和更高的灵敏度,是环境友好的绿色萃取技术。[中国渔业质量与标准,2014,4(6):32-41]

三辛胺从硫酸体系中萃取Cr_(2)O_(7)^(2-)的界面反应动力学研究

采用改进的动态单滴法 ,研究了用三辛胺 (TOA)在硫酸介质中萃取Cr2 O72 - 的界面反应动力学 ,得到界面反应方程 .实验结果表明 ,在 pH =1的溶液中 ,( 2 5± 1 )℃时TOA萃取Cr2 O72 - 的反应对水相中的Cr2 O72 - 浓度呈一级反应 ,对TOA的浓度呈 0

SDE与SPME用于蜂蜜中有机氯农药分析的前处理

就蜂蜜中有机氯农药的分析对比了SDE(一滴溶剂萃取)与SPME(固相微萃取)两种预处理技术,并对影响SDE萃取的相关因数进行了条件优化.结果表明,优化后的SDE不仅在相同的浓度范围内有更好的线性关系(相关系数R为0.9974～0.9999),而且增宽了P,P′-DDT的线性范围,降低了检出下限,并具有省钱省时、基体干扰小的优点.因此,用SDE-GC-uECD检测蜂蜜中残留有机氯农药的方法是简便、准确、快速、易行的.

HPMBP单独萃取钕(Ⅲ)的速率和萃取机理

对1—苯基—3—甲基—4—苯甲酰基—5—吡唑酮(即HPMBP或HA)萃取钕(Ⅲ)的分配平衡进行了考察,发现萃合物的组成为NdA_3。用单液滴法研究此萃取过程动力学时发现,萃取速率与水相稀土离子Nd^(3+)浓度的一次方和有机相萃取剂浓度的一次方成正比,与水相[H^+]的一次方成反比。在水相中加入EDTA后,萃取速率明显降低,且与EDTA浓度的一次方成反比。实验证明,速率控制步骤为扩散控制步骤。

新型萃取技术-原子吸收光谱在食品内重金属分析中的应用

食品安全是人们普遍十分关心的问题,发展新的食品检测技术有关于民生的大事,具有十分的重要的意义。食品分析涉及营养成分、添加剂、有毒有害的有机农药残留和无机重金属杂质检测等多个方面。本文仅介绍了新型绿色萃取技术结合原子吸收光谱在食品中有毒有害重金属组分检测中的应用,绿色萃取技术包括固相萃取(SPE)、单滴微萃取(SDME)、分散液-液微萃取(DLLME)、浊点萃取(CPE等),以及室温离子液体(RTIL)、分子印迹聚合物(MIP)在萃取中的应用。引用文献50篇。