溶剂挥发法制备萃取剂微胶囊

萃取剂微胶囊的制备是利用微囊化方法将萃取剂包覆起来 ,解决传统液液萃取中的两相相分散、相混合、相分离以及溶剂的损失和设备结构复杂等问题 .用简单易控制的溶剂挥发法成功制备了聚砜及聚苯乙烯材料包覆的多种萃取剂 (如磷酸三丁酯 ,2 乙基己基磷酸 ,三辛胺和Aliquat 336 )微胶囊 ,并考察了壁材和分散剂的选择对不同萃取剂进行包覆的影响 ,同时研究了搅拌速度和膜溶液组成对微胶囊的形态、萃取剂包覆量的影响 .结果表明 ,(1)用聚砜作壁材可以包覆磷酸三丁酯、2 乙基己基磷酸 ,而用聚苯乙烯可以包覆三辛胺、Aliquat336 ;(2 )对于不同的O W乳液体系 ,只有选择合适的分散剂 ,才能得到理想球形状、分散性好的微胶囊 ;(3)增大搅拌速度可以降低液滴尺度 ,从而减小微胶囊粒径 ;(4)膜溶液组成的影响则表现在两个方面 ,一是膜溶液的粘度和两相界面张力是除搅拌速度外微胶囊粒径的决定因素 ,二是膜溶液中壁材与萃取剂的比例优化时 ,才能得到萃取剂包覆量高的微胶囊 .     

Kinetics and mechanism of stripping of Np(IV) by acetohydroxamic acid using a Lewis cell

Kinetic studies of stripping of Np(IV) from 30% Tri-Butyl-Phosphate/Odourless Kerosene (TBP/OK) into a nitric acid solution containing acetohydroxamic acid (CH₃CONHOH) have been investigated using a Lewis cell. The different parameters affecting the back-extraction rate of Np(IV) such as Np, TBP, nitric acid, nitrate, acetohydroxamic acid(AHA) concentration in addition to temperature, stirring speed and special interfacial area were separately studied and a rate equation was deduced. Results have been compared among themselves and other published works on similar systems. Mechanisms of stripping processes have been proposed.     

磷酸体系中微量稀土元素萃取动力学研究

采用新型恒界面池法进行了磷酸体系中用P204萃取La(Ⅲ),Sm(Ⅲ)和Y(Ⅲ)的动力学研究,考察了搅拌速度、温度、比界面积、磷酸浓度及萃取剂浓度等因素对萃取速率的影响.结果表明:磷酸体系中用P204萃取La(Ⅲ),Sm(Ⅲ)和Y(Ⅲ)的表观活化能E_a分别为27.0,22.2和21.1 kJ·mol~(-1),在体相P204浓度大于在液一液界面饱和吸附时的最低浓度C_(min)时,其在界面已达到吸附饱和,反应的主通道由界面变为体相,在该体系下P204萃取La(Ⅲ),Sm(Ⅲ)和Y(Ⅲ)反应为体相化学反应和扩散反应混合控制.     

Kinetics and mechanism of stripping of Pu(IV) by <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylhydroxylamine using a Lewis cell

The kinetics of back-extraction of Pu(IV) from 30% Tri-Butyl-Phosphate/Odourless Kerosene (TBP/OK) into a nitric acid solution containing N,N-dimethylhydroxylamine (DMHAN) have been investigated using a Lewis cell. The different parameters affecting the back-extraction rate of Pu(IV) such as plutonium, nitric acid, DMHAN concentration in addition to temperature, stirring speed were separately studied and a rate equation was deduced. The activation energy of this process is 28.4 kJ/mol.     

Kinetic studies on the solvent extraction of uranium(VI) from phosphoric acid solution with HDEHP using laser-induced optical fiber fluorimetry

The laser-induced optical fiber fluorimetry has been used for the first time to analyse the concentration of uranium(VI) in the kinetic studies on the extraction of uranium(VI) between 0.5 mol L H₃PO₄ solution and HDEHP-cyclohexane system with Lewis cell. The effects of stirring speed, temperature and concentration of uranium(VI) and HDEHP on the rate of extraction were examined. These data show that the extraction rate of uranium(VI) in this system is controlled by the chemical reaction process at the interface. The rate equations and the rate constants of the forward and reverse extractions were obtained. The mechanism of the extraction has been discussed.     

铒在HBTMPTP-正庚烷/水溶液间的传质动力学

在(30±0.5)℃下,用层流恒界面池研究了铒在HBTMPTP-正庚烷-0.2mol/L(H,Na)Ac萃取体系中的传质动力学.测定了该体系的界面张力,考察了水相酸度、萃取剂浓度、氯离子浓度、温度和比界面对萃取速率的影响.实验表明,在本实验条件下,萃取过程属于扩散控制过程.Cyanex302中的杂质具有动力学的协萃作用.     

Cr(VI) ion removal from artificial waste water using supported liquid membrane

In this study, a novel flat-type synergic-supported liquid membrane was evaluated with a mixture of N-methyl-N,N,N-trioctylammonium chloride (Aliquat 336) and tributyl phosphate (TBP) as the carrier and kerosene as the diluent to remove Cr(VI) from synthetic waste water. The main parameters involved in the process were identified and optimised. The parameters were divided into two groups, those that were independent and those having an interaction. The parameters of the carrier/kerosene volumetric proportion and stirring rate were optimised individually due to their nature. The optimal values of these parameters were 0.5 and 500 min^?1, respectively, for a constant carrier/kerosene ratio and stirring rate in the designed experiments using the response surface method (RSM). The four parameters of TBP/Aliquat 336, chromium concentration in the feed phase, feed and product pH were optimised using RSM; it was observed that the TBP/Aliquat 336 ratio, feed pH, pH of the stripping phase and interaction of this parameter with feed concentration have the most important effects on the removal of Cr(VI). The optimal levels of these parameters were 0.61, 71.75 mg L^?1, 3.5 and 12.66 for the ratio of TBP/Aliquat 336, feed chromium concentration, pH of the feed and pH of the product, respectively. An experimental removal rate of 94.63 % at the optimized levels was obtained.     

含氟硫酸体系HEH/EHP萃取铈(Ⅳ)的动力学研究

采用层流恒界面池法研究了2-乙基己基膦酸单2-乙基己基酯(HEH/EHP)萃取含氟复杂硫酸体系中铈(Ⅳ)的动力学。考察了搅拌速度、水相金属离子浓度、萃取剂浓度、酸度和温度对萃取速率的影响。试验结果表明:萃取反应为一级反应,萃取反应的正向表观活化能为50.8 kJ·mol-1,属于化学反应控制。试验得到萃取动力学方程为R=k[Ce(HF)(HSO4-)3+]1.05[H2A2]2.07[H+]-2.43,并探讨了反应机制。     

Kinetic studies on the solvent extraction of uranium(VI) from phosphoric acid solution with HDEHP using laser-induced optical fiber fluorimetry

Laser-induced optical fiber fluorimetry has been first used to analyze uranium(VI) concentration in the kinetic studies on the extraction of uranium(VI) between 0.5 mol/l H₃PO₄ solution and HDEHP-cyclohexane system with a Lewis cell. The effects of stirring speed, temperature and concentrations of uranium(VI) and HDEHP on the rate of extraction were examined. These data show that the extraction rate of uranium(VI) in this system is controlled by the chemical reaction at the interface. The rate equations and the rate constants of forward and reverse extraction are obtained. The mechanism of the extraction is discussed.     

Determination of decabromodiphenyl ether in water samples by single-drop microextraction and RP-HPLC

This paper describes the development of a new method using single-drop microextraction (SDME) and RP-HPLC for the determination of decabromodiphenyl ether (BDE-209) in water samples. The effects of SDME parameters such as extraction solvent, microdrop volume, extraction time, stirring speed, salt concentration, and sample pH on the extraction performance are investigated. Under optimal extraction conditions (extraction solvent, toluene; solvent drop volume, 3.0 microL; extraction time, 15 min; stirring speed, 600 rpm; no addition of salt and change of sample pH), the calibration curve was drawn by plotting peak area against a series of BDE-209 concentrations (0.001-1 microg/mL) in aqueous solution; the correlation coefficient (r) was 0.9998. The limit of detection was 0.7 ng/mL. The enrichment factor was 10.6. The precision of this method was obtained by six successive analyses of a 100 ng/mL standard solution of BDE-209, and RSD was 4.8%. This method was successfully applied to the extraction of BDE-209 from tap and East Lake water samples with relative recoveries ranging from 92.5 to 102.8% and from 91.5 to 96.2%, respectively, and the relative standard deviations (n = 3) were 4.4 and 2.2%. The proposed method is acceptable for the analysis of BDE-209 in water samples.     

Kinetic studies on the extraction of U(IV) by TBP in kerosene from nitrate medium

The kinetics of extraction of U(IV) by TBP in kerosene was investigated using a stirred Lewis cell. The effect of the different parameters affecting the extraction rate as well as temperature were separately investigated. The rate equation deduced from the experimental results show that the extraction of U(IV) is first order dependent on TBP concentration while it is of zero order with respect to U(IV), H⁺, NO ₃ ^– and HNO₃ concentrations. The data obtained show that the extraction process is governed by chemical reactions taking place at teh interface.     

磷酸三丁酯萃取脱硫废液中硫氰酸根的初步研究

焦炉煤气含污染物H_2S 5g/m~3-8gm~3、HCN1g/m~3-2.5g/m~(3[1]),目前主要用催化氧化-氨水吸收法(NH_3-OMC)工艺处理.由此产生的脱硫脱氰废液中主要含有NH_4SCN、(NH_4)_2S_2O_3等无机盐,其中,SCN~-及S_2O_3~(2-)浓度均影响脱硫催化剂的效率,规定其总浓度不得超过250g/L.     

Kinetics of reductive stripping of Pu(IV) in the tributylphosphate-kerosene/nitric acid-water system using dihydroxyurea

The kinetics of the reductive stripping of plutonium(IV) by dihydroxyurea (DHU) in 30% TBP/kerosene-HNO₃ system was studied with a constant interfacial area cell. The stripping rate of plutonium(IV) increases with the increase of the stirring speed of two phases and the interfacial area. The activation energy of this process is 28.4 kJ/mol. Under the given experimental conditions, the mass transfer of Pu is not controlled by redox reaction, but controlled by molecular diffusion from the organic phase to organic film layer and from the aqueous film layer to aqueous phase. The rate equation of reductive stripping (process is controlled by diffusion) was obtained as: r ₀ = k′[Pu(IV)]₀[DHU]_a ^0.16[HNO₃]_a ^−0.34. The rate constant k′ is (5.0±0.4)·10⁻² (mol/L)^0.18·min⁻¹ at 18.0°C.     

Synergistic effect of tri-<Emphasis Type="Italic">n</Emphasis>-butyl phosphate (TBP) or tri-<Emphasis Type="Italic">n</Emphasis>-octyl phosphine oxide (TOPO) with didodecylphosphoric acid (HDDPA) on extraction of uranium(VI) and thorium(IV) ions

Importance of removal of radioactive elements from wastewater was the motivation behind this work. Synergistic solvent extraction of U(VI) and Th(IV) ions from perchlorate solution using didodecylphosphoric acid (HDDPA) incorporated with tri-n-butyl phosphate (TBP) or tri-n-octylphosphine oxide (TOPO) as a synergists have been studied for the first time. The effects of HDDPA concentration, synergist’s concentration, pH values and temperature on the extraction process have been studied. The thermodynamic parameters of the extraction process for these ions were calculated. It was found that the synergistic contribution of TOPO is higher than TBP in the extraction of Th(IV) and U(VI).     

乳状液膜法分离水中镉

本文报道了用乳状液膜法分离镉的研究。在此分离体系中,以煤油作为膜溶剂,span80为表面活性剂,磷酸三丁酯(TBP)为载体,液体石蜡为膜增强剂。详细讨论了制乳时间、混合时间、搅拌速度,span80、TBP以及液体石蜡的浓度,乳水比和油内比,内相氨水和外相HCl溶液的浓度对分离的影响,确立了最佳分离条件。     

Study on the Extraction Kinetics of Ketoconazole with Hydroxypropyl‐β‐Cyclodextrin as a Selector

This paper reports on the kinetics of extraction of ketoconazole enantiomers in a Lewis cell, which accompanies by an inclusion reaction. The mass transfer model of the extraction process is established based on the homogeneous reaction mechanism and two‐film theory. Factors such as stirring speed, phase contact area, and ketoconazole concentration are separately investigated. The obtained data show the inclusion reaction is a fast reaction. The reactions have been found to be first order for ketoconazole enantiomers and second order for hydroxypropyl‐β‐cyclodextrin with forward rate constants of 1.716 × 10⁻³ m⁶/(mol²·s) for (−)‐ketoconazole and 2.067 × 10⁻³ m⁶/(mol²·s) for (+)‐ketoconazole.     

Optimization of Process Parameters of Osthole-Loaded PLGA Microparticles Prepared Using Emulsification–Solvent Extraction

Osthole-loaded poly(d,l-lactic-co-glycolic) acid (PLGA) microparticles were prepared by oil-in-water (o/w) emulsification. The organic phase in emulsions was extracted by conventional evaporation and supercritical fluid extraction of emulsions. A Box–Behnken experimental design was used to evaluate the effects and to optimize the variables. Results indicated that the effects from two variables, that is, the emulsification stirring speed and the ratio of osthole to PLGA, had statistically significant on the encapsulation efficiency, while another variable, that is, the volume ratio of o/w, has no independent impact on the encapsulation. The interactions exist between the ratio of osthole to PLGA and the stirring speed, and between the volume ratio of o/w and the stirring speed. A second-order polynomial model was well adjusted to predict response variables, and 90.9% encapsulation efficiency could be realized at optimized conditions. The encapsulation efficiency of microparticles obtained with conventional evaporation was higher than that with supercritical fluid extraction of emulsions. The release curve of osthole from the microparticles could be nicely fitted by the Weibull equation and the release follows Fickian diffusion.     

A comprehensive study for selective removal of Cr(VI) by asymmetric imidazolium bromide salts as environmentally-friendly extractant

The study was to determine selective removal and recovery of Cr(VI) from acidic media by solvent extraction (SX) using asymmetric imidazolium-based room temperature imidazolium bromide salts (ARTILs) as the extractants. The relevant parameters on the extraction and the stripping of Cr(VI) were investigated to identify optimum conditions. The optimum conditions were determined as equilibration time 5 minutes, acid concentration and type 0.5?mol/L H₂SO₄, stirring speed 1200?rpm, extractant concentration and type 0.5?mol/L ARTIL5, phase ratio 2.0 and stripping reagent type, and concentration 2.0?mol/L NH₃. In optimum conditions, decyl substituted ARTIL was best in extraction process about 99.7% of extraction rate, whereas moderately hydrophobic pentyl substituted ARTIL was best in stripping process about 70.0% of stripping rate. Also, the optimized process was found as so selective toward Cr(VI) in the presence of the other metal ions with an environmental-friendly liquid–liquid–based SX method.     

介电法研究溶液中分子间的缔合作用(I)

磷酸三丁酯(TBP)是一种重要的萃取剂,它已广泛地应用于许多金属的提取工艺中。在萃取过程中,水在两相间的转移对萃取过程产生重要影响。一些实验表明,TBP分子是通过氢键与水生成1∶1缔合物形式萃取水分子。但对该缔合物的物理化学性质研究尚未见报导。我们运用静态介电研究法,通过测定溶液介电常数,并应用向无限稀释外推手段,进一步证明TBP与H_2O的缔合作用,并测得TBP·H_2O缔合物的摩尔极化度、偶极矩和缔合平衡常数,进而求得缔合反应的自由能。     

Preparation of molecularly imprinted solid-phase microextraction fiber for the selective removal and extraction of the antiviral drug abacavir in environmental and biological matrices

In the present study, a molecularly imprinted solid-phase microextraction fiber (MIP-SPME_f) was synthesized and applied for the selective removal and extraction of the antiviral drug, abacavir (ABA). Morphology and structure characterization of fibers were performed by scanning electron microscopy and Fourier transform infrared spectra, respectively. The effects on the adsorption behavior of the process parameters were studied and the equilibrium data were fitted by the Langmuir, Freundlich and Langmuir-Freundlich models. The maximum adsorption capability (Q_max) was determined by Langmuir- Freundlich model and was 149 mg/g for MIP-SPME_f. In the next step, SPME methodology followed by liquid desorption and liquid chromatography with mass spectrometry (LC/MS) has been developed and evaluated for the determination of the target compound in environmental and biological matrices (surface waters, wastewaters and urine). Parameters that could influence SPME efficiency were investigated. Then, optimization of stirring speed, extraction time and salt content was carried out by using a central composite design (CCD) and response surface methodology (RSM). A quadratic model between dependent and independent variables was built. Under the optimum conditions (extraction time 40 min, stirring rate 650 rpm and salt content 0.3% NaCl w/v) the validated method presented a high sensitivity and selectivity with LODs and LOQs in the range of 10.1–13.6 and 33.3–43.9 ng/L, respectively. The developed method was successfully applied to the analysis of ABA in real samples. The percentage extraction efficiency ranged from 88 to 99% revealing good accuracy and absence of matrix effects.