Ion-Exchange Kinetics for the Removal of Potassium from Crude Polyols on Strong Acid Resins

Abstract

Batch dynamics for the uptake of potassium from crude polyols on Amberlite 252, a strong acid ion-exchange resin, are obtained over a wide range of conditions. Experimental data have been analyzed using a homogeneous model with finite solution volume. An increase of diffusion coefficients with the resin weight used in the purification is observed. An asymptotic maximum value, approaching the value of the diffusion coefficient in bulk solution, is reached for high resin weights or low values of external concentration. The heterogeneous nature of the resin matrix and the large size of the diffusing molecule is proposed as an explanation of this behavior. The proposed purification procedure finds general applicability for other polyol types, being economically and technically feasible.     

Hydraulic Testing of Ion Exchange Resins for Cesium Removal from Hanford Tank Waste

Abstract

The granular ion exchange resin SuperLig^® 644 is the ion exchange resin of choice for ¹³⁷Cs separation from Hanford tank wastes. Current testing activities are evaluating both ground gel and spherical resorcinol‐formaldehyde (RF) resins as alternatives to the sole‐source supplied SL‐644 while achieving comparable loading and elution performance. The purpose of this testing was then to compare the bed forces, resin particle breakage, and differential pressure across the resin bed during multiple load‐elute cycles. These tests were conducted in a small‐scale column with high flow rates to simulate the hydraulic conditions that would be experienced in a full‐scale column.     

离子交换树脂脱除地下水中的硝酸盐

地下水是我国华北地区最重要的饮用水水源之一,特别是华北农村生活饮用水几乎全部来自地下水。然而,华北又是我国地下水硝酸盐污染比较严重的地区。研究开发适合华北农村分散式供水特点的地下水脱硝酸盐技术,对于保障农村的饮水安全具有十分重要的意义,为此把简单、高效且投资和运行费用相对较低的离子交换法用于脱除地下水中的硝酸盐。考察了普通强碱性阴离子交换树脂Purolite A 300E和硝酸盐选择性强碱性阴离子交换树脂Purolite A 520E脱除地下水中硝酸盐的效果,比较了地下水中SO42-和Cl-等阴离子对两类不同树脂交换性能的影响。结果表明,Purolite A 300E和Purolite A 520E树脂均能有效地去除地下水中的硝酸盐,两者的NO3--N饱和交换容量分别为49.02和48.54 mg/g。但是,当地下水中含有较高浓度的SO42-或Cl-时,Purolite A 520E脱除硝酸盐的效果明显优于Purolite A 300E。     

优化控制古龙酸离子交换工艺条件

控制好离子交换工艺条件,避免古龙酸溶液中出现钠盐,提高古龙酸收率和质量。     

Regeneration of Mixed Solvent by Ion Exchange Resin: Selective Removal of Chloride and Sulfate

Abstract

The selective extraction of sulfate and chloride ions from mixed solvent solutions was investigated. The mixed solvents consisted of water and 50 to 100%‐w (salt‐free solvent) ethylene glycol. The extraction was measured for mixed solvent solutions containing only sulfate and chloride, and mixed solvent solutions saturated with trona (sodium sesquicarbonate, Na₂CO₃ · NaHCO₃ · 2H₂O(s). Three anion exchange resins, Dowex 1X8‐50, Dowex 21K‐Cl, and Dowex MSA‐1, were investigated for their chemical and physical resistance to the mixed solvent carbonate/bicarbonate solutions, for their swelling behavior in the different mixed solvents, and for their extraction efficiency for chloride and sulfate.

The loading of the ion exchangers was fitted to a Langmuir‐type sorption model. While the extraction from trona‐free mixed solvents was well reproduced, the loading of the ion exchangers with chloride and sulfate from trona‐saturated mixed solvent solutions did not fit the sorption model. It appears, rather, that under these conditions chloride and sulfate are “salted out” of the bulk solution and driven into the ion exchangers.     

连续环状离子交换色谱分离技术

本文介绍了一种新型制备色谱分离技术──连续环状离子交换色谱ＣＡＣ，建立了二维稳定连续环状离子交换色谱的数学模型。在一定条件下经过适当转化，二维稳态ＣＡＣ过程可转化为一维非稳定色谱过程。分别改变ＣＡＣ进料浓度、进料流速及冲洗流速等操作条件，测定了ＣＡＣ对果葡糖的分离性能。同时，用固定床线性色谱理论对ＣＡＣ进行预测，其预测值与实验结果较好地相吻合。实验得出，连续环状离子交换色谱对果葡糖具有较好的分离性能。     

Sulfamethazine Retention from Water Solutions by Ion Exchange with a Strong Anionic Resin in Fixed Bed

Veterinary antibiotics such as sulfonamides were detected in the environment from animal excreta in soils, contaminating soil surface and then groundwaters by percolation. The contaminated waters can enter in this way into drinking water treatment plants (DWTPs). On the other hand, direct wastewaters from humans or animals or pharmaceutical industries disposals are discharged in wastewater treatment plants (WWTPs). These water and wastewater treatment plants are not designed to remove highly polar micropollutants like antibiotics. Removal of pharmaceuticals by adsorption and ion exchange constitutes a promising technique for its low cost, easy regeneration, and selective removal of pollutants. This work studies the removal of sulfamethazine (SMZ). The SMZ retention capacity of an anionic ion exchange resin, Lewatit MP500, was determined. Equilibrium and kinetics were studied and equilibrium constants and diffusivity values were obtained using different models. Load and elution breakthrough curves were plotted to evaluate ion exchange operation in a fixed bed column. In the elution step, 100% SMZ was recovered in all cycles and could be concentrated up to twelve times, thus facilitating its final treatment or removal. Load and elution breakthrough curves were simulated using a fixed bed model in which axial dispersion was considered the parameter model fit.     

Recovery of Sinapic Acid from the Waste Effluent of Mustard Protein Isolation by Ion Exchange Chromatography

Sinapic acid present in the waste stream of yellow mustard protein isolation was purified by strong base Dowex (1 × 8, Cl^?) ion exchange chromatography. The ratio of loading volume to resin bed volume was 19:1. Approximately 80 % of sinapic acid was adsorbed. The column was washed with two bed volumes of water to remove remaining undesirable components. Approximately 75 % of sinapic acid adsorbed by the resins in the column was eluted by ten bed volumes of a solution containing 0.9 M acetic acid and methanol (4:6, v/v). Up to 15 adsorption and regeneration cycles resulted in only a slight, 3–5 %, reduction in ion exchange capacity, indicating that this is a viable approach to the recovery and purification of sinapic acid. The recovery of this valuable nutraceutical ingredient improves the economic viability of an integrated extraction process for this Canadian oilseed crop.     

MIEX—DOC离子交换树脂的饮用水除砷研究

对新型阴离子交换树脂MIEX—DOC@的除砷性能进行了研究,考察了该树脂除砷容量、对三价砷[As（m）]和五价砷[As（V）]的去除能力、不同离子和水体pH值对树脂除砷[包括As（Ⅲ）和As（V）]效率的影响。结果表明,MIEX-DOC~树脂对人工配制高砷水（O．1mg·L-1）的除砷容量约为0．0051mg·mL-1;对As（Ⅲ）和As（V）的去除能力相当;常见的共存离子对树脂除砷效率有抑制或促进影响;不同pH值下,MIEX—DOC@树脂除砷效率不同,但对0．1mg·L-1的高砷水的除砷效率均达到50％以上。对农村高砷水的实地中试研究表明,当源水砷浓度约为0．1mg·L-1时,出水砷浓度低于0．05mg·L-1达到《生活饮用水卫生标准》（GB5749—2006）的农村小型集中式供水和分散式供水水质指标。成本分析结果表明,采用国产MIEX-DOC净水设备的除砷效果与进口设备相当,但除砷成本较低（0．56元·t-1）,在我国农村高砷饮用水处理中有一定应用潜力。     

离子交换法处理含硫酸铜废水的研究

运用离子交换法对电镀废水中硫酸铜进行吸附,富集废水中硫酸铜,达到回收再利用的目的。研究不同类型的树脂对硫酸铜吸附能力强弱,硫酸铜浓度及流速不同时树脂对硫酸铜的吸附能力。并且对树脂的解吸过程进行了研究,为低浓度含铜废水的合理回收提供依据。     

应用离子交换树脂生产高纯度的癸二酸

介绍应用离子交换树脂工艺生产含铁量在PPM级的癸二酸。     

弱碱性多胺基纤维的制备及结构性能研究

以工业化生产的普通商品级腈纶为基体,采用先交联后胺化的两步法,以水合肼为交联剂,二乙烯三胺为胺化试剂制备弱碱性多胺基纤维,并考察了反应温度、反应时间、二乙烯三胺的用量等工艺条件对合成纤维影响,得出温度135℃,反应时间3.5 h,胺用量4%时为最佳反应条件;制备的纤维断裂强度为1.6～1.7 cN/dtex,交换容量大于3.0 mmol/g。用红外光谱和扫描电镜表征了纤维的基本结构,对反应机理和产物的分子结构做了初步探讨。     

阳离子交换树脂催化乙二醇单乙醚酯化反应研究

本文用国产三种阳离子交换树为催化剂进行了乙二醇单乙单醚与醋酸酯化生成乙二醇单乙醚醋酸酯的反应，考查了了反应条件，筛选出Ｄ７２氢最离子交换树脂催化剂，并确定了最佳反应条件。     

离子交换膜的应用技术

离子交换膜具有分离效果好、能耗少和环保等特点,已经逐渐被应用于化工、海水脱盐、废水治理等领域。根据离子交换膜的分离机理不同,可将其在水处理中的应用分为电渗析、扩散渗析和Donnan渗析等三种,对三种分离方法的机理作了详细介绍,并举例说明了离子交换膜在水处理中的巨大潜力。     

热处理对离子交换法制备光致变色玻璃光色性能的影响

热处理对离子交换法制备光致变色玻璃光色性能的影响王民权，陈庆云，樊先平（浙江大学材料科学与工程学系３１００２７）ＥｆｆｅｃｔｏｆＨｅａｔＴｒｅａｔｍｅｎｔｏｎｔｈｅＰｈｏｔｏｃｈｒｏｍｉｃＰｒｏｐｅｒｔｉｅｓｏｆＰｈｏｔｏｃｈｒｏｍｉｃＧｌａｓｓｂｙ...     

离子色谱法分离有效霉素中主要组分

建立的一种简单、有效的方法,以一种强碱性阴离子交换树脂为吸附剂,纯水为洗脱剂,利用自制的连续加压洗脱装置分离得到3种高纯度的有效霉素常量组分,这些组分中含有胺基环醇结构,是用于合成高附加值的α-糖苷酶抑制剂类抗糖尿病药物的重要中间体。     

Polyols and Polyurethanes from Crude Algal Oil

The composition of crude algal oil was analyzed and determined by several methods. Oil was converted to polyols by ozonolysis, epoxidation, and hydroformylation. Ozonolysis gave a polyol with lighter color but a low OH number and was unsuitable for polyurethane applications. Epoxidation also improved the color and gave a polyol with an OH number around 150 mg KOH/g, which with diphenylmethane diisocyanate gave a homogeneous, rubbery, transparent sheet. Desirable rigid foams were prepared with the addition of water to the formulation. Hydroformylation was carried out successfully giving an OH number of about 150 mg KOH/g, but the polyol was black. Casting the polyurethane sheet was difficult due to the very high reactivity of the polyol. Polyurethane foam of lower quality than from epoxidation polyol was obtained. More work on optimization of the foaming system would improve the foam. Crude algal oil is a viable starting material for the production of polyols. Better results would be obtained from refined algal oils.     

Release of Nanoparticles from Ion Exchange Resins and Their Detection

Nanoparticles released from commercial ion exchange resins were analyzed by laser-induced breakdown detection (LIBD). It was shown that virgin resins release a considerable amount of nanoparticles which may harm sensitive production lines, if the resins are used without proper pretreatment. Particle release is reduced to below 1 ppb after regeneration and rinsing of the resins. However, the nanoparticle concentration can still be detected quantitatively by LIBD.     

Metathesis of Ionic Liquids: Continuous Ion Exchange by Donnan Dialysis

Ionic liquids (IL) are salts that have extraordinary low melting points below 100 °C. While only a very limited number of possible IL can be synthesized directly, the vast majority is prepared via the synthesis of a precursor IL with the desired cation and a subsequent anion exchange. This paper presents the continuous anion exchange by Donnan dialysis in aqueous solution with anion exchange membranes. The retention of the anion exchange membranes used in this work for inorganic and IL cations was found to be R > 99 %. The average integral transport coefficients were determined for the exchange of chloride/acetate, chloride/hydroxide and bromide/hydroxide for various IL and classical salts. The values of the integral average transport coefficients were found to be independent of the investigated counterions. Process modeling was applied to optimize the flow conditions to reach an anion exchange > 98 %. Ultrapure hydroxide solutions and acetates of common classes of IL cations were prepared with a conversion of the reactant anions of > 99 % and cationic impurity contents of < 1 %.     

碱性条件下NaY分子筛水热交换反应的研究

对碱性条件下的分子筛离子水热交换反应进行了研究。结果表明,离子交换反应为吸热反应,交换反应等温线为d型,交换反应为一级反应,表观活化能Ea为10．05kJ／mol。