凝胶型强酸型阳离子交换树脂分离阿卡波糖:平衡、动力学与热力学研究(英文)

Acarbose, a potentα-glucosidase inhibitor, is widely used as an oral anti-diabetic drug for the treatment of the type 2, non-insulin-dependent diabetes. In this work, a gel type strong acid cation exchange resin 001×4 was applied to isolate acarbose from fermentation broth. It was demonstrated that cation exchanger 001×4 displayed a large adsorption capacity and quick exchange rate for acarbose. The static adsorption equilibrium data were well fitted to the Langmuir equation. Column adsorption experiments demonstrated that high dynamic adsorption capacity was reached at bed height of 104.4 mm, feed flow rate of 1.0 ml·min-1 and acarbose concentration of 4.0 mg·ml-1. Under the optimized conditions, the column chromatography packed with cation exchanger 001×4 recovered 74.3%（by mass） of acarbose from Actinoplanes utahensis ZJB-08196 fermentation broth with purity of 80.1%（by mass）, demonstrating great potential in the practical applications in acarbose separation.     

Adsorptive Removal of Nitrate and Phosphate from Water by a Purolite Ion Exchange Resin and Hydrous Ferric Oxide Columns in Series

Elevated concentrations of nitrate and phosphate in surface and ground waters can lead to eutrophication, and nitrate can also cause health hazards to humans. The adsorption process is generally considered to be an efficient technique in removing these ions provided that the adsorbent is highly selective for these ions. Removal of nitrate and phosphate from a synthetic water (50 mg N/L as nitrate, 15 mg P/L as phosphate) and a wastewater (12.9 mg N/L as nitrate, 5.9 mg P/L as phosphate) using a Purolite A500P anion exchange resin and a hydrous ferric oxide (HFO) columns (60 cm height, 2 cm diameter, flow rate 1 m/h) in series containing 1–10% (w/w) of these adsorbents and the remainder anthracite (90–99%) were studied. Data from batch adsorption experiment at various concentrations of adsorbents satisfactorily fitted to Langmuir adsorption isotherm for nitrate and phosphate on Purolite with adsorption maxima of 64 mg N/g and 7 mg P/g and only for phosphate on HFO with adsorption maxima of 14 mg P/g. Both batch and column experiments showed that Purolite selectively removed nitrate and HFO selectively removed phosphate. The Purolite column BTC time was greater for nitrate than for phosphate. At the highest percentage by weight of Purolite almost all nitrate was removed in batch study and up to 1000 min in column study, but it was not able to remove a comparatively high percentage of phosphate. However, when the effluent from the Purolite column was passed through the HFO column almost all phosphate was removed. The two columns when set up in series also removed almost all nitrate and phosphate from the wastewater.     

Nitric acid and sodium hydroxide generation by electrodialysis using bipolar membranes

An electrodialysis process with bipolar membranes was used to generate HNO3 and NaOH from NaNO3 which can be found in industrial waste waters. The current efficiency of this process is limited by proton leakage through the anion exchange membrane (AEM), co-ion leakage through bipolar membranes (BPM) and water transport through the ion exchange membranes. Three cell configurations using three or two compartment cells with different anion or cation exchange membranes (CEM) in stack series were used and compared. Electrodialysis with three compartments gives the best current efficiencies for nitric acid and sodium hydroxide production from sodium nitrate.     

Adsorption of 2,4-D on Mg/Al–NO3 layered double hydroxides with varying layer charge density

Layered double hydroxides (LDHs) have high surface area and high anion exchange capacity, so they have been proposed to be an effective scavenger for contaminants. In this study, the adsorption of 2,4-dichlorophenoxyacetate (2,4-D) on Mg/Al–NO₃ LDHs with varying layer charge density was investigated with particular attention on the effect of the orientation of the interlayer nitrate. Three Mg/Al LDHs were synthesized with Al³⁺/(Al³⁺ + Mg²⁺) molar ratios of 3.3 (LDH3), 2.6 (LDH4) and 2.1 (LDH5). The results of adsorption experiments showed that LDH5 exhibited an S-type isotherm with a low 2,4-D adsorption capacity due to the low accessibility of 2,4-D to the interlayer space. The accessibility was restricted by the small basal spacing of LDH5 as a result of the parallel orientation of the interlayer nitrate with respect to the hydroxide sheet. Thus, the 2,4-D adsorption occurred mainly on the external surface of the material. On the contrary, LDH3, which has the highest layer charge density among the samples, contains nitrate with an orientation perpendicular to the hydroxide sheet of LDH3. The interlayer nitrate was readily exchanged by 2,4-D. Thus, in addition to the adsorption on the external surface, the replacement of the interlayer nitrate by 2,4-D contributed to a higher adsorbed amount of 2,4-D; the 2,4-D adsorption of LDH3 exhibited an L-type isotherm. For LDH4 that contained interlayer nitrate with both parallel and perpendicular orientations, the adsorption characteristics were between those of LDH3 and LDH5. This work has demonstrated the dependence of 2,4-D adsorption characteristics on the nitrate orientation in LDHs, as a consequence of changing layer charge density.     

Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange resins

EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process, using hydrophilic copolymer EVAL as the fiber substrate. The microstructures of the membrane adsorbents were observed, and the pure water fluxes, BSA rejection, and static adsorption capacities of membrane adsorbents for BSA were measured. The effect of the resin-filled content on membrane performance has been discussed. The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity, and the adsorption capacity increased with the quantity of the resin-filled content. The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65% at pH 4.5.     

Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange resins

EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process, using hydrophilic copolymer EVAL as the fiber substrate. The microstructures of the membrane adsorbents were observed, and the pure water fluxes, BSA rejection, and static adsorption capacities of membrane adsorbents for BSA were measured. The effect of the resin-filled content on membrane performance has been discussed. The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity, and the adsorption capacity increased with the quantity of the resin-filled content. The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65% at pH 4.5.     

Macroporous polymeric ion exchangers as adsorbents for the removal of cationic dye basic blue 9 from aqueous solutions

Two macroporous cation‐exchange resins, Purolite C145, a strongly acidic cation macroporous resin, and Purolite C107E, a weakly acidic cation‐exchange resin, were used to remove the dye Basic Blue 9 (BB9) from an aqueous medium. Batch adsorption experiments were carried out to analyze the effect of various parameters, such as the phase contact time, initial dye concentration, initial solution pH, resin dose, and temperature. The experimental equilibrium data were evaluated by the Langmuir, Freundlich, and Dubinin–Radushkevich (DR) adsorption models. The Freundlich model better described the adsorption processes of the BB9 dye onto both cation exchangers, and the monolayer adsorption capacities were established as 31.9846 mg/g (C145) and 27.77 mg/g (C107E) at 20°C. The values of the mean free adsorption energy (E) obtained from the DR model suggested a porous structure of the adsorbents and proposed ion exchange at the main mechanism of the adsorption process. The values of the thermodynamic parameters showed that the retention of the cationic dye was a spontaneous and endothermic process. Environmental scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize the sorbent and also to validate the adsorption mechanism as ion‐exchange ones. The desorption experiments by a batch method were performed with different solutions: 0.1 and 1 mol/L HCl, 2.5 mol/L H₂SO₄, CH₃OH, and a mixture between 1 mol/L HCl and CH₃OH. Desorption performed with sulfuric acid was shown to be most effective because more than 85% of the adsorbed dye was removed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39620.     

棉花模板Zn/Ti/Fe-LDO吸附水中硝酸盐机制

通过共沉淀-焙烧法制备以棉花为模板的Zn/Ti/Fe焙烧态类水滑石（YLDO）和无棉花模板的Zn/Ti/Fe焙烧态类水滑石（NLDO）,运用SEM、N₂吸附法、FTIR和XRD对其进行表征,考察YLDO和NLDO对水中硝酸盐的吸附机制及其紫外光催化再生的机理。结果表明,YLDO在形态中引入棉花的遗迹,比表面积增大为74.8 m²·g^-1,大孔数量增加;在化学成分上引入了C元素,提高了吸附性能;形成磁性物质,可通过磁性分离回收。pH为7、298 K时,YLDO对水中硝酸盐的最大吸附量为66.57 mg·g^-1,比NLDO增加了22.6%。YLDO和NLDO吸附硝酸盐的吸附等温线符合Langmuir方程,吸附动力学可用准二级动力学方程来描述,吸附热力学研究表明吸附过程为自发吸热过程。吸附饱和的YLDO和NLDO可在紫外光照射下再生,5次再生循环后仍保持较高的吸附性能。YLDO可通过吸附-磁分离-紫外光催化再生工艺有效去除水中硝酸盐,不产生二次污染,在硝酸盐废水处理中具有潜在的应用前景。     

处理高浓度氨氮废水的阳离子交换树脂筛选

目前树脂种类繁多,给处理高浓度氨氮废水的树脂选型带来困难。根据离子交换理论,利用001×7、D61和D001三种阳离子交换树脂,模拟研究了氮肥厂废水（氨氮浓度为915 mg·L^-1）氨氮的吸附等温式,在30～50 min内三种树脂对氨氮的吸附基本可达到平衡,吸附等温线均符合Freundlich吸附模式;进而研究了这三种树脂对废水中氨氮吸附的选择性系数、工作交换容量和离子交换速率。结果表明,用D61树脂处理含高浓度氨氮的废水效果较为理想,可以相对较少的用量,使处理后水质达到相关排放标准的要求。     

无机离子交换剂的Na-NH4^＋离子交换特性

研究以天然沸石为基体制备无机离子交换剂的方法;利用离子交换剂的吸附等温曲线,可得到阳离子最大的交换容量;通过离子交换剂的吸附动力学曲线,可求得吸附平衡时间。结果表明,以改性剂M为改性材料,在天然沸石与改性剂M质量比为4：1时制得的无机离子交换剂的阳离子交换容量最高,常温时能达50mg／g,平衡吸附时间约为2h。     

盐响应型蛋白质吸附阳离子交换膜

通过简单可控的“一锅法”将聚甲基丙烯酸-3-磺酸丙酯钾盐（PSPM）接枝到化学稳定性良好的富含叔胺基的聚醚砜酮（PTA）膜表面,制备得到盐响应型阳离子交换膜（PTA-GS）。以中性时带正电的溶菌酶（Lys）和带负电的牛血清白蛋白（BSA）作为模型蛋白质,系统研究了PTA-GS膜对蛋白质的静态吸附性能、吸附动力学以及盐响应的吸附性能,并采用等温吸附模型、吸附动力学模型对实验结果进行拟合。结果表明,PTA-GS膜对Lys的吸附更符合Redlich-Peterson、Langmuir等温吸附模型和拟二级动力学方程。在25℃,中性缓冲溶液中PTA-GS膜对Lys和BSA的平衡吸附量具有显著差异,它们的饱和吸附量分别为(174.2±22.8)mg/g和(8.1±2.5)mg/g。PTA-GS膜对Lys的吸附量随盐浓度的升高而降低,其在含1mol/L氯化钠的缓冲溶液中再生后蛋白质脱附率可达79.3%。研究结果可为简单制备吸附性能优异的盐响应型离子交换膜提供新思路,并为阳离子交换膜上蛋白质的吸附行为研究提供指导。     

Al-substituted tobermorite: shows cation exchange

It has been found that the tobermorite family--fundamental to cement chemistry can exhibit base exchange behavior. Several Al-substituted tobermorites were synthesized and these 11Å type tobermorites were discovered to have cation exchange as well as selective cation adsorption properties. For example, Al-substituted tobermorite (synthesized from a mixture of clinoptilolite and mortar) has a cation exchange capacity of 56 meq/100g and a selective Cs adsorption K_d of 3400 (ml/g). The cation exchange and selective properties of Al-substituted tobermorite are analogous to those of zeolites because of its rigid structure but unlike those of smectites or vermiculites where the basal spacing varies with the nature of the interlayer cation.     

NOx adsorption on MnO2/NaY composite: an in situ FTIR and EPR study

The NO, NO/O₂, and NO/O₂/H₂O adsorption on MnO₂/NaY (5 and 15 wt.% MnO₂) composite catalyst and NaY has been studied by means of in situ FTIR and EPR spectroscopy at elevated temperatures and during heating under reaction-like conditions. NO adsorption and co-adsorption of NO and O₂ on NaY and MnO₂/NaY proceeds via oxidation of NO forming NO₂⁻ and NO₃⁻ species. Whereas the manganese dioxide preferably acts as oxidising agent, the zeolite stores the NO_x species as nitrite and nitrate ions in the solid. In the presence of oxygen, the nitrate formation is enhanced due to additional oxidation of NO through gaseous oxygen leading to NO₂. Dimerisation of NO₂ to N₂O₄ and following disproportionation of the latter causes the formation of NO⁺ and NO₃⁻ species which are associated with nucleophilic zeolitic oxygen and especially alkali cations of the zeolite, respectively. The presence of oxygen facilitates reoxidation of Mn²⁺ which keeps more Mn ions in the active state. Pre-adsorbed water and higher amounts of water vapour in the feed hinder the NO adsorption by blocking the adsorption sites and shift the nitrate formation to higher temperatures. The quantities and thermal stability of the nitrates formed during NO and NO/O₂ adsorption differs which points to a different mechanism of nitrate formation. In the absence of gaseous oxygen, nitrates are formed by participation of only lattice oxygen. In the presence of oxygen, nitrate formation by dimerisation and disproportionation reactions of NO₂ dominates. The manganese component of the composite catalyst supports the oxidation of NO to nitrite and subsequently to nitrate. During this process Mn⁴⁺ is reduced to Mn²⁺ as evidenced by in situ EPR measurements.     

铁锰复合氧化物对As(Ⅲ)、As(Ⅴ)的吸附研究及其在沼液中的应用

研究了铁锰复合氧化物（FMBO）吸附去除As（Ⅲ）、As（Ⅴ）的性能。结果表明FMBO对As（Ⅲ）、As（Ⅴ）均具有较好的吸附能力,其饱和吸附量分别为111.10、71.40 mg·g^-1。As（Ⅲ）和As（Ⅴ）是通过与FMBO表面的Fe-OH基团进行交换并形成内层络合物的形式被FMBO吸附,且As（Ⅲ）的吸附是吸附和氧化共同作用的结果。另外,沼液中共存离子对As（Ⅲ）和As（Ⅴ）的吸附有不同的影响。Zn²⁺能够增加FMBO对As（Ⅲ）、As（Ⅴ）的吸附量,且增加幅度随着Zn²⁺浓度的增加而增加;磷酸根对As（Ⅲ）、As（Ⅴ）的吸附有明显的抑制作用,当磷与砷的分子摩尔比为1时,FMBO对As（Ⅲ）、As（Ⅴ）的吸附量分别降低了34.70%、31.50%;但是有机物（腐殖酸、动物蛋白及尿素）对FMBO吸附As（Ⅲ）、As（Ⅴ）的影响不大。利用FMBO对实际沼液中的砷进行吸附,结果表明砷的去除率平均达到65%左右,使吸附后某些沼液中砷的浓度达到生活饮用水标准和地表水排放标准。因此,将FMBO用于砷污染的沼液及水体的治理具有很好的应用前景。     

The conditions of cationic exchange with the use of recycling polystyrene derivative,the product of sulfonation by silica sulfuric acid

Growing amount of waste plastics has become an environmental problem on a global scale. This study presents an investigation of the conditions of cleaning water from heavy metal ions using chemically recycled polystyrene. To get effective ion exchangers, the sulfonation of virgin polystyrene and expanded polystyrene wastes were obtained using silica sulfuric acid. As it turned out, the use of this solid sulfonating agent simplifies the separation of the polymeric product from the acid and the solvent in comparison to conventional sulfonation methods. The ion exchange behavior of copper and zinc cations in the yielded sulfonated derivatives of polystyrene was studied. Batch shaking adsorption experiments depending on contact time, pH, temperature, and dosage of adsorbate were carried out. The stability of resin to cyclical adsorption and regeneration (column experiment) was also investigated. We report that resins have a high adsorption efficiency with total ion exchange capacity (IEC) about 2.6 meq g^?1, which drops with decreasing pH owing to competition between protons H⁺ and metal cations, whereas with the increasing resin doses the removal of cations rises for a constant initial metal concentration. The speed of cation exchange for yielded adsorbents was even better than for commercial resins. After 360 cyclical adsorption and regeneration in column, resin had working IEC of about 2.3 meq g^?1. The study shows that cation exchange resin from polystyrene wastes can be used as an efficient adsorbent for the removal of heavy metal ions from water. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Adsorptions of Some Heavy Metal Ions in Aqueous Solutions by Acrylamide/Maleic Acid Hydrogels

Abstract

In this study, acrylamide—maleic acid (AAm/MA) hydrogels in the form of rod have been prepared by γ-radiation. They have been used for adsorption of some heavy metal ions such as uranium, iron, and copper. For the hydrogel containing 40 mg of maleic acid and irradiated at 3.73 kGy, maximum and minimum swellings in the aqueous solutions of the heavy metal ions have been observed with water (1480%) and the aqueous solution of iron(III) nitrate (410%), respectively. Diffusions of water and heavy metal ions onto hydrogels have been found to be of the non-Fickian type of diffusion. In experiments of uranyl ions adsorption, Type II adsorption has been found. One gram of AAm/MA hydrogels sorbed 14–86 mg uranyl ions from solutions of uranyl acetate, 14–90 mg uranyl ions from solutions of uranyl nitrate, 16–39 mg iron ions from solutions of iron(IV) nitrate, and 28–81 mg copper ions from solutions of copper acetate, while acrylamide hydrogel did not sorb any heavy metals ions.     

Kinetics and Equilibrium Studies for the Removal of Cobalt,Manganese, and Silver in Ethanol using Dowex 50W-x8 Cation Exchange Resin

Organic solvents such as ethanol, find a wide range of applications in fuel, pharmaceutical industries, food industries, and paint formulations, among others. The removal of Ag(I), Co(II), and Mn(II) ions in ethanol by cation exchange resin, Dowex 50W-x8, was investigated. The adsorption characteristics of metal ions onto Dowex 50W-x8 resin were described by Langmuir isotherms. The maximum sorption exchange capacities at 298 K were obtained as 47.4 mg g^?1, 52.6 mg g^?1, and 58.5 mg g^?1 for Ag(I), Co(II), and Mn(II), respectively. The data was also fitted to Temkin and Dubinin-Radushkevich adsorption isotherm models to evaluate other adsorption properties. The ion exchange of silver, cobalt, and manganese on cation exchange resin followed pseudo-second-order kinetics, and the intraparticle diffusion was rate-determining step. The thermodynamic parameters indicated that the sorption of metal ions onto Dowex 50W-x8 resin was spontaneous (negative ΔG°) and endothermic in nature (positive ΔH°) implying that the adsorption capacity increased with increasing temperature. The resin can be regenerated by eluting metal ions with 3.0 mol L^?1 HNO₃ followed by washing it with 10 mL of Millipore water and 10 mL of 2.0 M NaOH, respectively. The proposed method was applied for metal ion removal in real ethanol samples.     

氢氧化镁处理酸性含铁废水的研究

以氢氧化镁作为吸附剂处理酸性含铁废水的结果表明,该方法操作简便,铁去除率高,可达98%以上。氢氧化镁对Fe3＋的饱和吸附量达32.86 mg/g。氢氧化镁回收后,经轻烧处理变成氧化镁,仍可以处理含铁工业废水,且可多次使用。吸附等温线的测定表明,Mg（OH）2对Fe3＋的吸附为典型的化学吸附。     

Adsorption of Th(IV) onto Al-pillared rectorite: Effect of pH, ionic strength, temperature, soil humic acid and fulvic acid

The adsorption of Th(IV) onto Al-pillared rectorite as a function of rectorite concentration, Th concentration, pH, ionic strength, temperature, soil humic acid (HA) and fulvic acid (FA) was studied by using batch technique under ambient condition. The results indicated that the adsorption of Th(IV) onto Al-pillared rectorite strongly depended on pH and ionic strength, and the adsorption of Th(IV) increased with increasing Al-pillared rectorite concentration. The presence of HA/FA enhanced Th(IV) adsorption at low pH and reduced Th(IV) adsorption at high pH. The adsorption of Th(IV) decreased with increasing temperature, indicating that the adsorption process of Th(IV) onto Al-pillared rectorite was exothermic. The experimental data of Th(IV) adsorption were analyzed with the Freundlich and Langmuir models, showing that the Freundlich model fitted the adsorption data better than the Langmuir model. The adsorption of Th(IV) on Al-pillared rectorite may be dominated by surface complexation and cation exchange also contributed partly to Th(IV) adsorption.     

Specific surface area of spinel oxides by Zn-ion adsorption (ZIA). Case of dry and hydrous Co3O4: feasibility and limitation

Co₃O₄ powders prepared by thermal decomposition of nitrate (TDN) and by precipitation in aqueous solution (PAS) have been investigated in relation with the zinc-ion adsorption (ZIA) method of in situ measurement of specific areas at the solid-liquid interface. The ZIA method seems feasible with dry TDN powders, while high solubility and cation exchanges hinder the method with hydrous PAS powders. The ZIA surface areas of dry Co₃O₄ are approximately the BET surface areas.