阴离子交换柱分离不同价态砷的研究及其应用

利用醋酸型AG 1-X8阴离子交换树脂和氯化物型AG 1-X8阴离子交换树脂对As(Ⅴ)和As(Ⅲ)吸附的差异,实现As(Ⅲ)和As(Ⅴ)的有效分离。过滤和酸化后的水样流经树脂交换柱(75mm×5.3mm i.d.)时,醋酸型AG 1-X8阴离子交换树脂可吸附As(Ⅴ);而As(Ⅲ)可通过树脂柱。被吸附的As(Ⅴ)用0.12mol/L HCl淋洗出来,在此过程中醋酸型树脂转化为氯化物型树脂。该树脂交换柱可多次循环使用。本方法简单易行,适用于野外现场条件下高砷地下水中As(Ⅲ)和As(Ⅴ)的分离和准确测定;用于检测水铁矿除砷过程中砷价态变化。结果表明,缺氧条件下水铁矿对As(Ⅲ)和As(Ⅴ)的吸附动力学特征遵循假二级反应动力学模式,内扩散不是控制As(Ⅲ)和As(Ⅴ)吸附的因素。随着时间的推移,膜扩散对吸附的控制作用增强。     

Utilization of anion exchange resin Spectra/Gel for separation of arsenic from water

Arsenic in drinking water is one of the most challenging health hazards facing mankind today. Arsenic is a naturally occurring carcinogen and creates epidemiological problems through chronic ingestion from drinking water. Arsenic is present in water primarily as As(III) or As(V). Removal of both As(III) and As(V) from water by adsorption on strong base anion-chloride has been studied. Arsenic concentration was measured by Inductively Coupled Argon Plasma (ICP) analysis. The resin was regenerated and the adsorbed arsenic fractions were eluted by using 2 M NaCl. The effect of different parameters that influence adsorption process, such as relative arsenic and resin concentrations, retention time, and pH, were investigated. Results obtained revealed that As(III) was poorly adsorbed, whereas As(V) was successfully retained on the resin. The adsorption process was optimized by using 1 g resin for 16 ppm As(V) at pH 9 for 30 min. The removal efficiency of As(V) was 99.2%.     

Selective removal of nitrate by using a novel macroporous acrylic anion exchange resin

An anion exchange resin NDP-5 has been prepared successfully and applied on the selective removal of nitrate from SO₄^2-/ NO₃^- binary co-existence system.The composition and morphology of NDP-5 were confirmed by FT-IR and SEM.The NDP-5 resin exhibits the completely different behavior on the adsorption capacity,adsorption kinetic and the effect of the completing anion in the absence or presence of sulfate,compared to D213.And,the resultants of kinetic are well fitted by the pseudo-first-order and pseudo-second-order models.These results are very important to develop novel resins with great features.     

Chromatographic separation of cytidine triphosphate from fermentation broth of yeast using anion-exchange cryogel

A novel separation method was developed to isolate directly cytidine triphosphate (CTP) from fermentation broth of yeast using anion-exchange supermacroporous cryogel. The anion-exchange cryogel with tertiary amine groups was prepared by graft polymerization. The breakthrough characteristics and elution performance of pure CTP in the cryogel bed were investigated experimentally and the CTP binding capacity was determined. Then the separation experiments of CTP from crude fermentation broth of yeast using the cryogel column were carried out using deionized water and 0.01 M HCl as washing buffer, respectively. The chromatographic behavior was monitored and analyzed. The purity and concentration of the obtained CTP in these processes were determined quantitatively by HPLC. The maximal purity of CTP obtained at the condition of 0.01 M HCl as washing buffer and 0.5 M NaCl in 0.01 M HCl as elution buffer reached 93%.     

Isolation of ATP from a yeast fermentation broth using a cryogel column at high flow velocities

This communication presents an effective method for isolating adenosine triphosphate (ATP) from a yeast fermentation broth using an anion‐exchange supermacroporous cryogel column at high flow velocities. The breakthrough and elution behaviors of pure ATP in the cryogel bed were investigated at flow velocities of 2, 5, and 10 cm/min and the ATP binding capacities were determined. Then the ATP‐containing yeast fermentation broth was employed as the test feedstock and various chromatographic runs were conducted to isolate ATP by the cryogel at different high flow velocities. The ATP samples obtained were analyzed quantitatively by HPLC. The results showed that even at a flow velocity of 5 or 10 cm/min, a product purity of 97.4 or 98.0% can be achieved, illustrating the potential of the present method for separation of high‐purity ATP directly from fermentation feedstock at high flow velocities.     

EDTA金属螯合物阴离子交换色谱行为研究

本文报道Ｚｎ（Ⅱ）、Ｃｒ（Ⅲ）、Ｆｅ（Ⅲ）等金属－ＥＤＴＡ螯合物的阴离子交换色谱行为．采用ＰＲＰ－１００阴离子色谱柱，以２．０ｍＬ／ｍｉｎ．流速、４ｍｍｏｌ／Ｌ苯甲酸为淋洗液，电导检测器检测，可以很好地分离Ｚｎ－ＥＤＴＡ２－、Ｃｒ－ＥＤＴＡ－、Ｆｅ－ＥＤＴＡ－．方法可用于废水中金属离子的检测．     

Adsorption of some elements from hydrochloric acid by anion exchange

Anion exchange behavior of 20 anionic chemical species was studied focusing on hydrochloric acid solutions. Elution characteristics for some of these anions were followed by using a basic anion exchange resin. Estimates of distribution coefficients in 10⁻³-9 mol/l acid were obtained by analytical determinations of these elements in column effluent solutions. The adsorption data observed in this medium suggests many applications in analytical separations.     

Analytical models for describing cation adsorption/desorption kinetics as considering the electrostatic field from surface charges of particles

Surface charges of particles together with the adsorbed counter ions in diffuse layer can set up a strong electrostatic field around the particles in aqueous solution. The existent kinetic models for describing cation exchange on solid/liquid interface were either empirical or semi-empirical, and in which the electrostatic field is not considered. In this paper, as considering the important effect of electrostatic field around particles on cations adsorption/desorption, for the first time the dynamic distribution equations of cations in diffuse layer for adsorption and desorption processes in both flow method and batch technique have been established. Those equations clearly show how the cation concentration changes with time in different position of diffuse layer during the cation exchange process, and the corresponding new kinetic models have been obtained upon them. The new models indicate that, in both flow method and batch technique, for the adsorption process, experimental results should appear zero order kinetic process caused by the strong force adsorption in the initial stage of adsorption, and then transform to the first order kinetic process of the weak force adsorption; and for the desorption process, however, only first order kinetic process may exist. The new models are essentially different from the classic apparent or empirical kinetic models since all the parameters have their defined physical meanings in the new models, thus the rate parameters in the new models have the potential to theoretically predict. Theoretical analyses also indicated that, the adsorption/desorption rate in flow method experiment will be much higher than that in batch technique experiment.     

Adsorption kinetics of fluoride on iron(III)-zirconium(IV) hybrid oxide

Fluoride occurs in some drinking water sources at levels that are hazardous to health. Tests were conducted to assess the ability of a mineral-based adsorbent to take-up fluoride ion. Consequently, in search of novel adsorbent media, crystalline and hydrous iron(III)-zirconium(IV) hybrid oxide (IZHO) was synthesized, and tested to determine its capacity and kinetics for fluoride adsorption. The Fourier Transform Infrared (FTIR) spectrum of IZHO indicated the presence of Fe–O–Zr linkage which showed hybrid nature of the synthetic oxide. The optimum pH range for fluoride adsorption was ranged between 4.0 and 7.0. The analyses of the isotherm equilibrium data using the Langmuir and the Redlich–Peterson model equations by linear and non-linear methods showed that the data fitted better with latter model than the former. Thermodynamic analysis showed spontaneous nature of fluoride adsorption, and that took place with the increase of entropy. The kinetic data obtained for fluoride adsorption on IZHO at pH 6.8 (±0.1) and room temperature (303±2 K) described both the pseudo-first order and the reversible first-order equations equally well (r ²= ∼0.98–0.99), and better than pseudo second order equation (r ²= ∼0.96–0.98) for higher concentrations (12.5 and 25.0 mg/dm³) of fluoride. The kinetics of fluoride adsorption on the mixed oxide took place with boundary layer diffusion. External mass transport with intra-particle diffusion phenomena governed the rate limiting process, which has been confirmed from the Boyd poor non-linear kinetic plots.     

Adsorption kinetics for arsenic removal from aqueous solutions by untreated powdered eggshell

The batch removal of arsenic from aqueous solution using low-cost adsorbent (powdered eggshell) under the influences of initial arsenic ion concentrations (0.50 to 1.50 mg/L), pH (3.2 to 11.5) and particle size of eggshells (63 to 150 μm) were investigated. Eggshells were collected from Obafemi Awolowo University, Ile-Ife, washed with distilled water, air dried, ground into powder and sieved into different sieve sizes using British standard sieve. Powdered eggshells were stored in a desiccator for use. Adsorption isotherms and dynamics of arsenic onto PES were studied. The study revealed that there was a slight reduction in the rate of adsorption of arsenic ion onto the larger particle size, but adsorption capacity and parameters were unaffected. Powdered eggshell with particle size of 63 μm removed up to 99.6% of the 1.5 mg/L of arsenic ion in synthetic water within the first 6 hours but decreased to 98.4% and 97.4% when the powdered eggshell particle sizes were increased to 75 and 150 μm respectively. The pH optimum for arsenic removal was 7.2. The adsorption isotherms and adsorption dynamic kinetic studied through the use of graphical method revealed that Freundlich, activated sludge adsorption and pseudo second-order kinetic models correlate significantly with the experimental data with correlation coefficient of not less than 0.964.     

耐高温阴离子交换树脂的合成及在环氧乙烷催化水合反应中的应用

我们合成了一种新型结构的季铵型阴离子交换树脂催化剂(NC-1),并将其转型为碳酸氢根型应用于环氧乙烷(EO)催化水合反应.并用NC-1、D201树脂催化EO水合反应进行了考察.NC-1型离子交换树脂催化剂,因具有较好的热稳定性,其使用寿命比D201树脂提高到数十倍.同时,还设计了一种“二步法”新型水合工艺,与传统水合工艺相比,这种工艺有效地抑制了树脂催化剂的膨胀.在使用105h后,催化剂的膨胀率由原来的76%下降到5%左右.     

Anion exchange membrane with viologen moiety as anion exchange groups and generation of photo-induced electrical potential from the membrane

An anion exchange membrane with a viologen moiety was prepared by the reaction of a film of chloromethylated polysulfone and 4,4′-bipyridine. The anion exchange membrane showed a high electrical resistance and a high transport number of anions due to the development of high crosslinking by the diamine. After the membrane had been swollen with ethylene glycol, photo-voltage and photo-current (82 mV, 410 nA at 200 kΩ load, 160 μm thick membrane) were generated from the membrane upon photo-irradiation.     

Preparation of a novel magnetic resin for effective removal of both natural organic matter and organic micropollutants

A novel,bifunctional,hypercrosslinked.magnetic resin W2 was prepared using divinylbenzene(DVB) and glycidyl methacrylate(GMA) as comonomers in three steps(i.e.,suspension polymerization, amination and post-crosslinking reactions).To evaluate the adsorption of natural organic matter(NOM) and organic micropollutants(OMPs) on the obtained resin W2,two magnetic resins Wl(the precursor of W2 before post-crosslinking) and WO(the precursor of Wl before amination) were chosen for comparison.The results indicated that W2 would be a promising material for the removal of both NOM and OMPs from aquatic environments.     

A DFT study of the effect of copper promotion upon iron oxide surface species

Cluster models for sites on the {1 1 1} surface of Fe₃O₄ were used to study the strength of bonding of water-gas shift intermediates using density functional theory. Three site models were used, representing an unpromoted catalyst, a catalyst where copper cations substitute for iron cations below the surface and a catalyst where copper cations substitute in the surface. The strengths of bonding of oxygen, carbon dioxide, dissociated water and dissociated formic acid were all observed to decrease by less than 20 kJ mol⁻¹ when copper substituted below the surface, but they decreased by 60–80 kJ mol⁻¹ when copper substituted in the surface of the catalyst. A minimum energy structure for molecularly adsorbed water was not identified because all attempts to do so resulted in dissociation.     

Solvent desorption of asphaltenes from solid surfaces

The main goal of this paper is to compare the ability of different organic solvents to desorb asphaltenes from stainless steel surfaces. The asphaltenes were extracted from a North Sea crude oil by precipitation. The organic solvents are characterized based on their Hansen solubility parameters (HSPs). The adsorption of asphaltenes was followed by means of a Quartz Crystal Microbalance with Dissipation (QCM-D). The asphaltene desorption efficiency of the solvents tested varied between 20% and 70%, with pyridine as the most efficient solvent. Carbon disulfide was found to be a poor desorption solvent, indicating the importance of solvent polarity. A simple model based on the HSPs seemed to give a good quantitative explanation of experimental desorption experiments.     

Preparation of magnetic anion exchange resin and their adsorption kinetic behavior of reactive blue

Magnetic anion exchange resin(MD-1) was prepared from quaternization of magnetic copolymeric resin(glycidyl methacrylate -eo-divinylbenzene).For comparison,magnetic resin MD-0 without quaternization and non-magnetic resin(D-1) were also synthesized for the adsorption process.It was found that the adsorption was mainly contributed to the chemical interaction between quaternary ammonium groups and reactive blue RXHC.Due to the smaller size,MD-1 had faster adsorption and desorption kinetics than D-1.Coupled with the advantage of easy separation,the magnetic anion exchange resin was considered to be superior to common anion exchange resin in removal of reactive dye.     

Application of anion‐exchange imidazolium silica for the multiphase dispersive extraction of phenolic acids

This paper reports the application of a multiphase dispersive extraction method to the extraction, separation, and determination of the phenolic acids from Salicornia herbacea L. using silica‐confined ionic liquids as sorbents. A suitable sorbent for phenolic acid extraction and separation was first identified based on the adsorption behavior of the phenolic acids on different silica‐confined ionic liquids. The sample was then mixed with the optimized sorbent and solvent to achieve multiphase dispersive extraction. The sample/sorbent ratio was optimized using theoretical calculations from the adsorption isotherm and experiments. After transferring the supernatant to an empty cartridge, an SPE process was used to separate the three phenolic acids from the other interference. Through systematic optimization, the optimal conditions produced high recovery rates of protocatechuic acid (91.20%), caffeic acid (94.03%), and ferulic acid (91.33%). Overall, the proposed method is expected to have wide applicability.     

新型树脂基水合锰氧化物对水体中磺胺嘧啶的降解去除

以大孔强碱阴离子交换树脂D201为载体, 采用离子交换和氧化还原方法制备了一种新型树脂基水合锰氧化物材料HMO-201. 考察了不同pH、 离子强度和溶解性有机质(DOM)含量条件下, 该材料对水体中磺胺嘧啶(SD)的去除能力. HPLC-MS分析表明, SD的高效去除是通过HMO-201的降解而非吸附方式实现的. 实验结果表明, pH为1.0时HMO-201在120 min内对0.01 mmol/L SD的去除效率为99.9%, 反应符合表观一级动力学模型; 体系的离子强度和DOM含量变化对SD的去除效率均无显著影响. 模拟环境离子强度和DOM浓度, 连续10批次实验中SD废水的去除效率在240 min内均大于99%; HMO-201的柱动态降解装置连续处理SD溶液2000床体积, 依然未检出SD. 表明HMO-201材料具有较稳定的重复利用性, 对环境中普遍存在的磺胺类抗生素药物具有着高效的降解去除效果, 具有广泛的应用前景.     

离子交换色谱法测定小球藻提取物中的核苷酸

建立了用阴离子交换色谱法测定小球藻提取物中的各种核苷酸的方法。用Shim PackWAX 1色谱柱 (5 0mm× 4 .6mmi.d .,粒度 3μm ,孔径 1 0 0nm) ,2 5mmol/L的磷酸二氢钠水溶液 (pH =3.5 ) ,流量梯度洗脱。检测波长 2 6 0nm。回收率在 97.5 0 %～ 99.4 0 %。该法简便 ,灵敏 ,重现性好 ,可以广泛应用于各类小球藻提取物和各类食品中的核苷酸的检测     

Preparation and application of a novel magnetic anion exchange resin for selective nitrate removal

正A novel magnetic anion exchange resin NDM-1 was prepared through suspension polymerization and then functionalized with ammonolysis and alkylating agents.Its application for selective removal of nitrate was performed in comparison with MIEX~.The results demonstrated that NDM-1 achieved higher efficiency in nitrate removal than MIEX~ did,with or without the existence of competing anion SO_4~(2-) ascribed to its longer alkyl chains on exchange sites.Combined with the advantage of easy separation due toγ-Fe_2O_3 implanted,the magnetic anion exchange resin NDM-1 was considered to be superior to MIEX~ for nitrate removal in practical application.