弱碱性树脂吸附分离丙酮酸的特性研究

Uptakes of pyruvic acid for two types of commercially available weakly basic polymer sorbents, D301G and D301R, have been measured over a wide pH range and at various salinities of MgSO4. The results show that the overloading adsorption of pyruvic acid occurs on both weakly basic polymer sorbents, and the overloading models can predict the experimental data of uptake very well. The overloading value for D301G is larger than that for D301R. The adsorption isotherm of pyruvic acid for both polymeric sorbents is greatly affected by the solution pH and MgSO4 concentration in the aqueous phase, and a high recovery efficiency of pyruvic acid from aqueous solution can be obtained at the solution pH around 2.     

以弱碱性树脂去除废水中5-氨基-2-氯苯-4-磺酸和盐酸

This research deals with an investigation of the adsorption of two acids, namely, 5-amino- 2-chlorotoluene-4-sulfonic and chlorhydric acids from their solution onto weakly basic resin. The screening of resins, kinetics, and isotherm were studied. The results indicate that the D301R is more appropriate for the removal of acids from solution. The adsorption of acids obeys Langmuir isotherm and the first-order kinetics model. Sorptive affinity of the two acids on D301R was found to be in the order of 5-amino-2-chlorotoluene-4-sulfonic acid〉 chlorhydric acid. Thermodynamic parameters for the adsorption of acids were calculated and discussed. The maximum removal of acids was observed around 97% and 76% at 25℃ for 5-amino-2-chlorotoluene-4-sulfonic acid and chlorhydric acid, respectively.     

三烷基胺萃取氨基磺酸及其废水的特性研究

p-Amino benzene sulfonic acid (PABSA) is selected as the solute with amphoteric functional group, Lewis acid and Lewis base, to be separated from its dilute solutions. An aliphatic, straight chain amine, Alamine 336, is used as the extractant, and kerosene, 1-octanol, chloroform, butyl acetate and benzene as the diluent. The effects of pH value of solution, extractant concentration, salt and types of diluent on the distribution coefficient, D, are studied. There is a peak of D value with pH value of solution, the polar diluents are favorable for extracting PABSA, and the salt in aqueous phase reduces values of D apparently. The extraction equilibrium is described using the mass action law, and the calculated data according to the proposed model agree with the experimental data well. Further, the extraction behavior for other amino benzene sulfonic acids, 1-amino-8-naphtol-3,6-disulfonic acid (H acid) and 4,4′-diaminostilbene-2,2′-disulfonic acid (DSD acid), is investigated in a wide pH value region. Finally. H acid and DSD acid are successfully removed from wastewater by the extraction with Alamine 336.     

Synthesis and characterisation of carboxylic acid and diphenylphosphine derivatives in the 1,3-diyne series: Spectral properties of polydiacetylene carboxylates

Symmetrically substituted 1,3-diynes containing hydroxyalkyl ( 1a-d ), bromoalkyl ( 1e-h ) (diphenylphosphinyl) ( 1i-k ) and carboxyalkyl ( 2a-d ) substituents have been prepared and characterised; the phosphine derivative ( 1k ) has been converted with alkyl iodides ( RI ; R = Me, Et) into bis(phosphonium) salts ( 1l and m ). During preparation of the diynedioic acid. ( 2a ), the non-centrosymmetrical diyne, HO₂CCH₂C?C—C?C(CH₂)₂OH ( 3 ), was also isolated. ⁶⁰Co γ-Irradiation of diacetylene monomers ( 2a – d ) and 10,12-tricosadiyn-1-oic acid gave the corresponding polydiacetylene derivatives ( 4a – d and 5 ), respectively. Rubidium salts of ( 4c ) and ( 4d ), a barium salt of ( 4c ), and a potassium salt of ( 5 ) were prepared and isolated; soluble potassium salts of the carboxylic acid polymers ( 4 ) were generated in aqueous solution. The effects of changes in pH on the UV/visible absorption spectra of aqueous solutions of selected carboxylic acid polydiacetylenes have been recorded, and are discussed.     

Adsorption equilibrium of amino acids and antibiotics on non‐ionic polymeric sorbents

Adsorption equilibria of two amino acids (phenylalanine and tryptophan) and two antibiotics (penicillin G and cephalosporin C) from aqueous solutions onto non‐ionic polymeric sorbents (XAD‐4 and XAD‐16) were investigated under various experimental conditions such as pH, temperature and organic solvents. The assumption that amino acids adsorbed on polymeric sorbents were desorbed by competitive adsorption with organic solvent as a desorbate was verified using binary adsorption data for amino acids (phenylalanine and tryptophan) and organic solvents (isopropyl alcohol and methanol) on XAD‐4 and XAD‐16. The experimental data were predicted by using multicomponent adsorption models of an Extended‐Langmuir (EL) equation and an ideal adsorbed solution theory (IAST) based on the Langmuir equation as a single‐component isotherm. Copyright © 2004 Society of Chemical Industry     

Chelating polymeric particles intended for the therapy of Wilson’s disease

Wilson’s disease is a genetic disorder that leads to a high accumulation of copper in multiple organs with subsequent toxic effects. In this paper, a gentle therapy to eliminate harmful copper concentrations in patients with Wilson’s disease is proposed using an oral administration of insoluble polymeric sorbents containing selective chelating groups for copper(II). The sorbents contained triethylenetetramine, N,N-di(2-pyridylmethyl)amine, 8-hydroxyquinoline or 8-hydroxyquinoline-5-sulfonic acid chelating groups bound to a methacrylate-based macroporous support. Nearly quantitative copper(II) uptake within minutes was achieved in buffers modeling the pH range present in the gastric environment (pH 2.0 and 4.0). The sorbents demonstrated chelating selectivity for copper(II) against zinc(II) with ratios of up to 1321. The sorbents demonstrated sufficient stability of the copper complexes against rechelation using studies in a model environment for the small intestine (the presence of chelating amino acids, pH 6.8).     

Novel sorbents based on silica coated with polyethylenimine and crosslinked with poly(carboxylic acid): Preparation and characterization

Novel sorbents based on silica coated with polyethylenimine (SilPEI) and crosslinked with poly(carboxylic acid) were prepared and characterized. These sorbents are to be used for heavy metal decontamination of aqueous solutions and have to be prepared in easy and ecological ways. A part of the carboxylic moieties [from ethylenediaminetetraacetic acid (EDTA) or citric acid] reacts with some of the amine groups of polyethylenimine, initially coated onto the silica, whereas the other part remains free for further metal complexation. By changing various parameters (temperature, pH, presence or absence of an amide‐forming agent), the conditions to prepare the best sorbent—that is, the sorbent exhibiting both a high capacity for metal complexation and good stability in an acidic medium (conditions for metal desorption or stripping)—were defined. The sorbent was prepared by a reaction of 1 g of SilPEI and 1 g of EDTA in water at 0°C, pH 6, during 10 h, using 0.5 g of 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide hydrochloride as a coupling agent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 799–805, 2003     

以弱碱性树脂去除废水中5-氨基-2-氯甲苯-4-磺酸和盐酸：平衡及动力学

考察了废水中5-氨基-2-氯甲苯-4-磺酸（CLT）和盐酸（HCl）在弱碱性离子交换树脂D301R上的吸附。研究了吸附平衡及动力学行为。结果表明两种酸在D301R树脂上的吸附遵循Langmuir吸附平衡模型;CLT吸附动力学过程与二级反应模型相吻合;HCl与一级反应模型吻合得较好;吸附过程为孔扩散控制。CLT在树脂上的吸附度大于HCl。计算了吸附过程热力学参数并进行了讨论。     

Poly(sulfobetaine)s and corresponding cationic polymers. XI. Synthesis and aqueous solution properties of a cationic poly(methyl iodide quaternized ethyl vinyl ether/N,N‐dimethylaminopropyl maleamidic acid) copolymer

A copolymer prepared by the copolymerization of ethyl vinyl ether and maleic anhydride underwent amidoacidation with N,N‐dimethylaminopropylamine. The obtained ethyl vinyl ether/dimethylaminopropyl maleamidic acid copolymer was then reacted with methyl iodide to yield poly(methyl iodide quaternized ethyl vinyl ether/N,N′‐dimethylaminopropyl maleamidic acid) (MIQEDMAPMA). The greatest difference from other polyelectrolytes was the carboxylic group on the polymer chain unit of MIQEDMAPMA. Its aqueous solution properties in various salts and at various pH values were studied by measurements of the reduced viscosity and intrinsic viscosity. The reduced viscosity and intrinsic viscosity of this cationic polyelectrolyte were related to the types and concentrations of the added salts. The tendency of the salt effect was similar to that of other polyelectrolytes; that is, soft salt anions were more easily bound to the quaternary ammonium (R₄N⁺) of MIQEDMAPMA than hard salt anions. Some salt ions strongly attracted the quaternary ammonium of the cationic polymeric side chain for the agglomeration of the polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2261–2269, 2003     

The effects of carboxylic acids on the aqueous dispersion and electrophoretic deposition of ZrO2

The agglomeration, electrokinetic properties and electrophoretic deposition behaviour of aqueous suspensions of ZrO₂ with carboxylic acid additives were studied in comparison with conventional pH adjustment. It was found that citric acid imparted negative zeta-potential values and electrosteric stabilisation to particles in suspensions at all pH levels. The examination of additions of carboxylic acids to ZrO₂ suspensions revealed that these reagents cause a sharp drop in zeta-potential at distinct addition levels, which correspond to surface saturation of the particles with negatively charged carboxylate groups. Adsorption cross sections of citric acid, EDTA and oxalic acid were evaluated from these results, showing that both citric acid and EDTA coordinate to ZrO₂ surfaces by two carboxylate groups while oxalic acid is coordinated by one group. The use of carboxylic acids was shown to facilitate superior electrophoretic deposition in comparison with zeta-potential modification by conventional pH adjustment through improved suspension stability.     

LSER modeling of extraction of succinic acid by tridodecylamine dissolved in 2-octanone and 1-octanol

Reactive extraction can be used for the recovery of carboxylic acids from fermentation broth. Through the formation of complex with extractants at the two-phase interface, the carboxylic acids are partitioned into organic solvents. But, the recovery of carboxylic acids is interrupted by the conditions of fermentation broth. In this work, kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in 2-octanone and 1-octanol have been carried out. Equilibrium and kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in two functional groups (alcohol and ketone) such as 2-octanone and 1-octanol are reported. All measurements have been carried out at 298.15 K. The results of the liquid–liquid equilibrium measurements have been correlated by a linear solvation energy relationship – LSER model which takes into account physical interactions.     

有机羧酸在弱碱性树脂上的吸附平衡

引　言有机羧酸是重要的化工原料 ,在化工、染料、食品及医药等领域有着广泛的用途 .有机羧酸的重要制法之一是发酵法 ,其特点是原料的利用及转化率较高 ,而分离费用一般占整个产品成本的 50 %～60 % [1].例如 ,乳酸发酵液中除乳酸和葡萄糖外还有乙酸、丁二酸、酒石酸、柠檬酸等常见的有机羧酸 ,其中约含乳酸 3.5%、乙酸 1 .0 % .此外 ,发酵法制备乳酸存在着明显的产物抑制现象 ,发酵液中的乳酸浓度过高将直接影响过程速率 .选择新的有机羧酸分离方法 ,保证在有利于发酵过程的条件下有效地分离发酵液中的有机羧酸 ,已经成为近年来稀溶液分离…     

Fabrication of halloysite nanotubes embedded thin film nanocomposite membranes for dye removal

Environmental friendly Halloysite nanotubes (HNTs) are used to fabricate novel nanofiltration membranes by in situ interfacial polymerization of piperazine and trimesoyl chloride. The removal of excess amine solution from the porous support membrane surface is a critical step to obtain defect free active layer. Hereby, two main removal tools for the excess aqueous amine solution; a rubber roll or air knife are compared to fabricate a defect free thin film nanocomposite (TFN) nanofiltration (NF) membrane. Removal by the rubber roll is eventuated more favorable than air knife in terms of the reproducibility of NF membranes by comparing salt rejections. By determining the removal step of excess amines, various HNTs concentrations are used to fabricate NF membranes and, these membranes are tested with salt and dye solutions at various pH and temperature ranges. R2 membrane (containing 0.02% [w/v] HNTs) performs the best flux results beside higher rejections of MgSO₄ (93.0%) and dye (99.5%). To evaluate the extreme conditionals, further performance tests such as pH and temperature resistance are also performed for R2 membrane. Considering the performances of R2 membrane, HNTs can be demonstrated for tailoring the balance between flux and separation performance of NF membranes.     

2-萘磺酸/硫酸在弱碱性树脂上的吸附平衡研究

Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of β-naphthalenesulfonic acid(NSA and sulfuric acid from their solution at 25℃ onto weakly basic resin D301R,Adsorption affinity of sulfuric acid on D301R was found to be much higher than that of NSA.The data of single-solute adsorption were fitted to the Langmuir model and the Freundlich adsorption model.The ideal adsorbed solution theory(IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria.The IAST coupled with the Langmuir and the Freundlich model for sulfuric acid and NSA.Respectively,yields the favorable representation of the bisolute competitive adsorption behavior.     

Chiral separation of mandelic acid by temperature‐induced aqueous two‐phase system

BACKGROUND: R‐mandelic acid is an important chiral pharmaceutical intermediate, which is commonly obtained by biotransformation. This work has focused on using novel chiral recognition technology, aqueous two‐phase extraction, for the chiral separation of mandelic acid. RESULTS: The copper (II) formed a 2:1 complex with β‐CD in an alkaline solution, which was isolated from solution by the addition of ethanol. The complex structure was characterized by IR and UV spectroscopy. The chiral recognition system was established by adding Cu₂‐β‐CD into the triton‐114 aqueous two‐phase extraction system, which preferentially recognizes the (R)‐enantiomer rather than the (S)‐enantiomer. Factors affecting the extraction mechanism were analyzed, namely the concentration of Cu₂‐β‐CD and tritonX‐114, the types of salts, pH, and temperature. It was found that the concentration of Cu₂‐β‐CD and temperature were the most important influencing factors for chiral separation of mandedlic acid. The experimental results showed that the ee values increased with pH and concentration of trition‐114, and the maximum ee was 67.91%. The addition of inorganic salt had a strong influence on ee, which decreased when salt was added into the aqueous two‐phase extraction system. CONCLUSION: A novel chiral recognition technology ‐ aqueous two phase extraction is reported in this paper.The tritonX‐114 aqueous two phase system have a good recognition ability for mandelic acid. Copyright © 2012 Society of Chemical Industry     

2,4-二羟基苯甲酸在3种树脂上的吸附特性

通过静态和动态吸附实验, 研究了717(凝胶型,强碱)、D201(大孔型,强碱)和D301R(大孔型,弱碱)3种阴离子交换树脂对水溶液中2,4-二羟基苯甲酸的吸附特性. 结果表明,717和D201在pH 4~11时、D301R在pH 3~9时吸附能力最好. 在pH=5及温度293~313 K、初始浓度0.6488~6.488 mmol/L条件下,D301R, 717和D201对2,4-二羟基苯甲酸的等温吸附规律均符合Freundlich模型,最大平衡吸附量分别为2.98, 2.66和2.54 mmol/g(吸附未达饱和),均为物理性自发吸附的放热过程. 动力学实验数据用准一级模型方程拟合比准二级更接近实验值. 5%(w) NaCl+2%(w) NaOH脱附液100 mL均可有效洗脱3种树脂上吸附的2,4-二羟基苯甲酸,脱附率达99%. 相同条件下,D301R树脂对2,4-二羟基苯甲酸的吸附性能优于D201和717树脂.     

Adsorption of heavy metal ions from aqueous solutions by porous polyacrylonitrile beads

The adsorption of Cu(II), Ni(II), Zn(II), and Pb(II) from aqueous solutions on acrylonitrile copolymer sorbents was studied. We prepared five types of sorbents from polyacrylonitrile by varying its concentration in the initial polymer solution and the composition of the coagulation bath, aiming to achieve a different porous structure. The specific area, pore volume, and pore radius of the sorbents were determined on a porosimeter. The porous structure was studied by scanning electron microscopy. Modification of sorbents with sodium hydroxide and hydroxylamine was carried out to form amidooxyme and carboxylic groups with proven complex‐forming properties toward heavy metal ions. The optimal pH of the sorption of metal ions was found. The adsorption kinetics were investigated. The order of polymer sorbents toward the sorption of Pb(II), Cu(II), Ni(II), and Zn(II) ions, and the order of heavy metal uptake were determined for all types of sorbents. The effectiveness of heavy metal desorption and the coefficient of recovery of sorption ability were determined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3036–3044, 2002; DOI 10.1002/app.2334     

丙酮酸化学萃取的盐效应

以三辛胺为萃取剂,在不同离子类型及离子强度下对丙酮酸的络合萃取过程进行了研究。结果表明,在一定pH范围内,随无机离子浓度的增加,丙酮酸分配系数随盐浓度的增加而迅速降低;萃后水相pH随盐浓度的增加均有不同程度的升高,在同一离子强度下,萃取剂浓度越高,萃后水相pH上升幅度越大。红外光谱的分析结果证实了无机阴离子可能通过同离子竞争,抑制了丙酮酸根离子与络合剂的离子对缔合作用,从而降低了萃取效果。     

The factors affecting the backward-transfer of Bovine Serum Albumin (BSA) from sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micellar solutions

The factors affecting the back-extraction efficiency of Bovine Serum Albumin (BSA, 65kDa, pI 4.9) solubilized in an AOT reverse micellar solution, prepared by the injection method, to an excess aqueous phase were investigated. In particular, effects of pH, the type of salt and its concentration in the excess aqueous phase were examined. Furthermore, by comparing CD spectra of the back-extracted BSA with the feed BSA, the structural changes of the protein during the extraction process were determined. The addition of 1:1 salt such as KCl or NaCl to the aqueous phase resulted in a 100% recovery of the protein to the aqueous phase at a pH higher than its isoelectric point pI. This high efficiency of the back-extraction might be due to the change in the interactions between the protein and micellar aggregates driven by the added salt. For 1 : 2 salts like MgCl₂ or CaCl₂, BSA was back extracted with lower than 20% extraction efficiency. Maximum efficiencies were achieved at about pH=7 and pH=8 for monovalent and divalent salts, respectively. From the C D spectra of back-extracted BSA, it was observed that denaturation of BSA was not significant during the extraction process.     

Catalytic oxidation with air of tartronic acid to mesoxalic acid on bismuth-promoted platinum

Mesoxalic acid (ketomalonic acid) was prepared by oxidative dehydrogenation with air of tartronic acid in aqueous solution on carbon-supported platinum-bismuth catalysts. By increasing the pH, using a higher catalyst/substrate ratio or increasing the temperature, higher yields could be obtained (maximum yield obtained of 65% at 80% conversion). The results obtained for this reaction and for the analogous catalytic oxidations of glyceric acid to hydroxypyruvic acid, and lactic acid to pyruvic acid, enabled a general reaction mechanism to be proposed for the selective oxidation of α-hydroxy acids to α-keto acids on platinum-bismuth catalysts. This revised version was published online in July 2006 with corrections to the Cover Date.