Separation of Bromelain by Aqueous Two Phase Flotation

Aqueous two phase flotation (ATPF) system of polyethylene glycol (PEG) and potassium phosphate is studied for the separation and partial purification of bromelain from the pineapple fruit (Annanus comosus L. Merryl). The effect of PEG molecular weight (1500–20000), concentration of phase forming components (PEG 12–18% w/w and potassium phosphate 14–20% w/w), system pH, nitrogen flow rate, and flotation time were studied and optimum conditions for ATPF were obtained. At optimum conditions of the system, i.e., 14% w/w PEG 1500, 18% w/w potassium phosphate, 80 mL/min of nitrogen flow rate and pH 7, maximum yield of 91.47% and purification fold of 4.26 were obtained. ATPF was found to be an effective technique for the purification of bromelain from pineapple fruit with higher extraction yield and purification fold as compared to aqueous two phase extraction (ATPE).     

二元小分子醇/盐双水相体系中磺胺嘧啶的分配行为

在双水相体系研究的基础上,建立了乙醇与正丙醇和硫酸铵形成的二元小分子醇/盐双水相体系萃取磺胺嘧啶的新方法,考察了盐种类和浓度、pH值以及静置时间对磺胺嘧啶分配行为的影响。结果表明,二元小分子醇/盐双水相体系可用于磺胺类抗生素分配行为的研究,体系组成为乙醇与正丙醇体积比例为1∶1,硫酸铵浓度为40%,pH值在4.0～5.0,温度25℃,静置10 h,磺胺嘧啶在该二元双水相体系中的分配系数达33.49,萃取率达96.97%。     

离子液体双水相萃取山楂黄酮和多糖的研究

采用分光光度法研究了山楂黄酮和多糖在[Bmim]BF4/(NH4)2SO4双水相体系的分配行为,探讨了离子液体浓度、(NH4)2SO4浓度、山楂用量和超声时间等因素对山楂黄酮和多糖萃取率的影响。确定最佳萃取条件为:离子液体[Bmim]BF4浓度0.26~0.30g·mL-1,(NH4)2SO4浓度0.08~0.10g·mL-1,山楂用量0.14~0.17g,超声时间15~20min,在此优化条件下,双水相上相中黄酮的萃取率为86.4%~96.0%、下相中多糖的萃取率为75.2%~76.0%。     

聚乙二醇-硫酸铵双水相萃取结晶紫的研究

利用分光光度法研究了结晶紫在聚乙二醇-硫酸铵双水相体系中的萃取行为,探讨了质量配比(mPEG/m(NH4)2SO4)、温度、结晶紫浓度对结晶紫的分配系数(cup/clow)及萃取率的影响。结果表明,在一定的温度和结晶紫浓度下,随着质量配比的减小,结晶紫的分配系数增大,萃取率略有降低;在一定的质量配比和结晶紫浓度下,随着温度的升高,分配系数显著增大,萃取率基本保持不变;在一定的质量配比和温度下,随着结晶紫浓度的增大,分配系数显著减小,萃取率基本保持不变;在mPEG/m(NH4)2SO4为1.25∶1、结晶紫浓度为6.536×10-5 mol.L-1、温度为50℃的条件下,萃取率高达99.81%。     

聚乙二醇/硫酸铵双水相体系萃取猪胰蛋白酶

采用聚乙二醇(PEG)/硫酸铵[(NH4)2SO4]双水相体系对猪胰蛋白酶分离进行了研究。通过综合考察酶分配系数、蛋白质分配系数、相比和回收率,探讨了PEG400质量分数、(NH4)2SO4质量分数、NaCl质量分数以及pH值对胰蛋白酶萃取的影响,并通过正交实验进一步优化实验条件,结果表明(NH4)2SO4质量分数和PEG浓度对胰蛋白酶的萃取影响大,在PEG400质量分数为24%、(NH4)2SO4质量分数为21%、pH值为4.2所组成的双水相体系下,可获得酶的高分配系数8.48,提取的胰蛋白酶活力达到1780 U/mL。     

两种双水相体系提取枇杷叶中黄酮的工艺研究

以枇杷叶为原料,利用双水相体系提取黄酮。考察了聚乙二醇-硫酸铵体系和乙醇-硫酸铵体系中各物质用量、料液比(g∶mL,下同)、pH值、提取温度、提取时间等条件对提取效率的影响,并对两种体系的提取效率进行了比较。结果表明:聚乙二醇-硫酸铵体系中,在聚乙二醇用量为2.0g、硫酸铵用量为1.5g、料液比为0.3∶10、pH值为9、提取温度为40℃、提取时间为1.5h的条件下,提取效率最高,达5.80%;乙醇-硫酸铵体系中,在无水乙醇用量为4.0mL、硫酸铵用量为1.8g、料液比为0.2∶10、提取温度为40℃、提取时间为1.0h的条件下,提取效率最高,达7.49%;可见乙醇-硫酸铵体系的黄酮提取效率高于聚乙二醇-硫酸铵体系。     

双水相与超声波耦合法提取香薷黄酮

用丙醇-硫酸铵双水相与超声波耦合法提取香薷中的黄酮,由正交试验确定提取的最优条件。结果表明,在每毫升水加入0.35g硫酸铵、丙醇与水的体积比为0.60、料液比1∶35(g/m L)、超声波提取40min的条件下,香薷黄酮的提取率可达9.39%。     

Purification of ice structuring protein complexes from winter wheat using Triton X-114 phase partitioning

Ice structuring proteins (ISPs) isolated from the cold-acclimated plants have a great potential in improving the quality of frozen foods. The purification of ISP complexes from winter wheat was achieved using an aqueous two-phase system of Triton X-114. The highly reactive phenols were removed, and the ISP complexes remained in the aqueous phase after phase separation. The ISP complexes treated by this procedure retained higher thermal hysteresis activity than those treated by ammonium sulfate method. The phase separation technique provides a simple and mild way for removing phenols from ISP complexes.     

醇/小分子有机物-无机盐二元双水相体系分离萃取甲基橙

基于小分子醇双水相体系和小分子有机物双水相体系,建立了正丙醇/丙酮-硫酸铵形成的二元双水相体系萃取甲基橙的新方法,研究了分相盐、醇及小分子有机物的类型、用量及比例、温度、溶液酸度、甲基橙浓度对甲基橙分配行为的影响。结果表明,硫酸铵浓度为30%,正丙醇∶丙酮=2∶1,溶液酸度在pH=5.5～6范围,温度为25℃,二元双水相体系对甲基橙有较高萃取率,可达89.57%和分配系数达到48.66。     

Purification of ice structuring protein complexes from winter wheat using Triton X-114 phase partitioning

Ice structuring proteins (ISPs) isolated from the cold-acclimated plants have a great potential in improving the quality of frozen foods. The purification of ISP complexes from winter wheat was achieved using an aqueous two-phase system of Triton X-114. The highly reactive phenols were removed, and the ISP complexes remained in the aqueous phase after phase separation. The ISP complexes treated by this procedure retained higher thermal hysteresis activity than those treated by ammonium sulfate method. The phase separation technique provides a simple and mild way for removing phenols from ISP complexes.     

Experimental studies on phase equilibria of PEG-water-dextran/ammonium sulfate systems and partitioning of albumin into two water-continuous phases

The clouding points and equilibrium concentrations of PEG/dextran/water and PEG /ammonium sulfate/water systems were experimentally determined for different molecular weights of PEG by titration method and direct determination of concentrations. In phase diagrams of PEG-water with ammonium sulfate or dextran, the addition of salt or dextran induced the phase separation of PEG-rich phases near the PEG-lean phases having the different partitioning of PEG. The concentrations of PEG in PEG-rich phases increase as the amounts of PEG or salt and dextran increase, while the concentrations of PEG in aqueous media decrease in any cases. The higher the molecular weight of PEG has, the wider the two-phase regions are. In dextran DT10 systems, the partition coefficients of egg albumin into PEG-lean phases increase with concentrations of dextran and the molecular weight of PEG. In ammonium sulfate systems, the partitioning coefficients showed a maximum, having lower partitioning at the very high and low concentration of salts. It is also observed that as the amounts of albumin increase, the partitioning of albumin into PEG-lean phase increases.     

三元共聚物防垢剂的合成与性能研究

以水为溶剂,过硫酸铵为引发剂,马来酸酐、乙酸乙烯酯和丙烯酸为原料,合成了三元共聚物防垢剂,并对其进行了性能评价。研究了三元共聚物的质量浓度、温度及体系pH值等条件对其防垢率的影响。结果表明,合成的马来酸酐/乙酸乙烯酯/丙烯酸三元共聚物防垢剂对碳酸钙的防垢效果较好。     

Dispersion copolymerization of acrylamide with acrylic acid in an aqueous solution of ammonium sulfate: Synthesis and characterization

Dispersion copolymerization of acrylamide with acrylic acid in an aqueous solution of ammonium sulfate using poly(2‐acrylamido‐2‐methylpropanesulfonic acid sodium) as the stabilizer and ammonium persulfate (APS) as the initiator was investigated. The influence of initiator concentration, stabilizer concentration, ammonium sulfate concentration, chain‐transfer agent concentration, and polymerization temperature on the copolymerization was discussed. The results showed that varying the ammonium sulfate concentration could affect the particle size and the intrinsic viscosity of the copolymer significantly. With increasing the stabilizer concentration, the particle size of the copolymer decreased first, and then increased, meanwhile the intrinsic viscosity of the copolymer decreased. The increase of initiator concentration, chain‐transfer agent concentration, and polymerization temperature resulted in the increase in the particle size. Polydisperse spherical particles were formed in the system, and the kinetics for the dispersion copolymerization were discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3685–3690, 2006     

L35-硫酸铵双水相体系萃取水溶液中Cr(VI)

以L35-(NH4)2SO4-H2O双水相体系萃取模拟废水中Cr(VI),考察了初始Cr(VI)浓度、水相pH值、胶束电荷调节剂1812用量、萃取时间、相分离时间、L35浓度、(NH4)2SO4浓度及萃取温度对Cr(VI)萃取率的影响. 结果表明,溶液pH值对Cr(VI)萃取率和分配系数影响最大;加入1812后,Cr(VI)萃取率和分配系数明显提高;随温度升高,两者均逐渐降低;随L35和(NH4)2SO4浓度增加,Cr(VI)萃取率逐渐提高并趋于恒定;萃取和相分离时间均较短;在最佳萃取条件下,Cr(VI)单级萃取率达92%(w),分配系数达15以上. 四级错流萃取的理论计算和实验结果基本一致,Cr(VI)浓度由2 g/L降到0.5 mg/L以下,达到国家排放标准. Cr(VI)依靠其相对疏水性以增溶方式及静电引力方式进入L35胶束内部而被萃取. 用NaOH水溶液对萃取相单级反萃取,Cr(VI)反萃率达99.5%(w)以上,浓缩倍数>4.     

Effect of surface active additives on partitioning of proteins and enzymes in poly(ethylene glycol)/dextran aqueous two-phase systems

The effect of anionic (sodium butylbenzene sulfonate, sodium butylmonoglycol sulfate), cationic (tetrabutyl ammonium bromide), nonionic(Tween 20) and amphoteric (proline) surface active additives on the partitioning of proteins and enzymes, such as BSA, lysozyme, glucose oxidase and β-lactoglobulin, in a bipolymeric aqueous two-phase system of polyethylene glycol and dextran has been studied. The partitioning of proteins and enzymes in the aqueous two-phase system is influenced by surface active additives depending upon their structure and charge. The amphiphiles themselves partition unevenly between the two phases. Their effect on protein partitioning can be explained on the basis of electrostatic and hydrophobic interactions. In the presence of ionic amphiphiles, proteins have an affinity for the other phase if an amphiphile carrying a charge of the same sign partitions to that phase. The hydrophobic effect contributes to protein partitioning if the proteins have significant members of surface hydrophobic amino acid residues. © 1998 Society of Chemical Industry     

丙烯酰胺/丙烯酸/甲基丙烯酸甲酯双水相共聚过程的成滴机理

在含聚丙烯酸钠（PAANa）的硫酸铵（AS）水溶液中,进行丙烯酰胺（AM）/丙烯酸（AA）/甲基丙烯酸甲酯（MMA）双水相共聚合反应,制备阴离子型聚丙烯酰胺水溶性聚合物分散液。采用动态激光光散射（DLS）在线检测了双水相聚合初期液滴形成及生长规律,发现液滴在反应初期存在聚并现象,滴径分布先变宽后变窄。采用气相色谱检测了共聚过程中各单体的残余量,推算聚合物链结构组成：反应前期聚合物链以AM和MMA链节为主,反应中期聚合物链以AM链节为主,反应后期聚合物链以AA和AM链节为主。提出了AM/AA/MMA双水相共聚过程的成滴机理,其中聚合物链上AA链节所带有的负电荷是聚合产物稳定分散、不易于凝聚的重要因素。     

三元正极材料前驱体MnxNiyCozCO3的合成及条件探究

将硫酸锰、硫酸钴、硫酸镍按物质的量比为0.54∶0.13∶0.13均匀混合配制成溶液,将混合溶液与一定浓度的碳酸氢铵溶液反应,得到三元材料前驱体MnxNiyCozCO3。分别探究了碳酸氢铵溶液的浓度、三元硫酸盐混合溶液与碳酸氢铵溶液的浓度比及反应温度对硫酸盐转化率的影响。结果表明：室温下,当碳酸氢铵溶液的浓度为0.30 mol/L,三元硫酸盐混合溶液与碳酸氢铵溶液的浓度比为1∶5时,硫酸盐的转化率可达91.20%。XRD结果表明产物 MnxNiyCozCO3与碳酸锰具有相同的晶相。SEM结果表明产物的形貌为粒径均匀的微米球（粒径为4~6 μm）。该方法简单有效,具有可行性,有望用于三元正极材料前驱体的规模生产。     

偶联阳离子表面活性剂和常用阴离子表面活性剂混合溶液的相分离和微观结构

The properties of aqueous two-phase system (ATPS) of mixed solution containing gemini cationic surfactant trimethylene-l,3-bis(dodecyldimethyl ammonium) bromide (12-3-12, 2Br-) and traditional anionic surfactant sodium dodecyl sulfate (SDS) with or without added salt have been studied. An ATPS is formed in a narrow region of the ternary phase diagram different from that of traditional aqueous cationic-anionic surfactant systems. In ATPS region, the lowest total concentration of surfactants varies with the mixing ratio of geminis to SDS. Photographs obtained from freeze-etching, negative-staining and transmission electron microscopy show that the microstructures of two phases are different from each other. Micelles and vesicles can coexist in a single phase. The addition of salts can change the phase diagram of ATPS. Furthermore, the added salts promote the aggregation of rod-like micelles to form coarse network structure that increase the viscosity of solutions. The negative ions of the added salts are the determining factor.     

PEG/（NH4）2SO4双水相萃取分离茶氨酸的研究

采用聚乙二醇(PEG)/(NH4)2SO4双水相体系萃取分离生产茶多酚所得废液中的茶氨酸,考察了PEG分子量与含量、硫酸铵含量、pH、温度、加盐(KCl、KBr、KI)、茶氨酸含量对双水相及萃取分离茶氨酸的影响。结果表明,PEG/(NH4)2SO4双水相萃取分离茶氨酸的适宜条件是:PEG平均分子量为4 000,质量分数为10%,硫酸铵质量分数为15%,pH约为6,30℃。在此条件下,茶氨酸的分配系数K1=0.16,蛋白质的分配系数K2=0.28,糖类的分配系数K3=9.8,茶氨酸在下相的萃取率为89.5%,可以将茶多酚废液中的茶氨酸与糖类及其他有颜色的杂质分开。     

离子交换膜-硫酸铵溶液体系的极限电流密度

采用六室膜组合的膜堆研究离子交换膜-硫酸铵溶液体系的电流-电压曲线,考察了离子交换膜(JCM-15和JAM-15)-硫酸铵溶液体系中硫酸铵浓度、流速和温度对极限电流密度的影响. 实验结果表明,离子交换膜-硫酸铵溶液体系的电流-电压曲线明显有3个区域：欧姆区域、平缓增加区域和过极限电流区域. 增加硫酸铵浓度、流速和操作温度均能提高单极膜的极限电流密度. 在相同的操作条件下,阴膜(JAM-15)的极限电流密度明显高于阳膜(JCM-15). 离子交换膜-硫酸铵溶液体系的极限电流密度与流速和硫酸铵浓度的关系符合Wilson修正式,对本工作所采用的膜,ilim=17.647C0.4570V0.5725(JAM-15), ilim=13.003C0.2918V0.3697(JCM-15).