UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 1: ACID DEPENDENCIES OF ACTINIDE IONS*

ABSTRACT

The uptake of several actinide ions [U(VI), Pu(IV), Np(IV), Th(IV] and Am(DI)) from nitric and hydrochloric acid solutions, and of U(VI) from near-neutral solutions by the new chelating ion-exchange resin, Diphonix^TM, has been investigated. Diphonix is a polyfunctional resin containing sulfonic and gem-diphosphonic acid groups chemically bonded in a styrene-divinylbenzene polymeric network. Comparison of the acid dependencies of the actinide ions uptake measured with Diphonix with those obtained using a commercial sulfonic -type resin and a resin containing both sulfonic and monophosphonic aCid groups, hat Shown that Diphonix binds the actinides via a different kind of chemical interaction, involving the.formation of chelate complexes through the phosphoryl groups of the gem-diphosphonic acids. As a consequence, Diphonix is superior to other resins in extracting actinide ions from very acidic solutions. A better performance of Diphonix is also observed with the uptake of uranium from neutral solutions. Conditions for efficient stripping of actinide species from the resin have been found.     

UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 2: ACID DEPENDENCIES OF TRANSITION AND POST-TRANSITION METAL IONS*

ABSTRACT

Diphonix^(tm)is a new dual-mechanism polyfunctional resin containing sulfonic and gem-diphosphonic acid groups. In Part 1 of this series the effectiveness of Diphonix in removing actinide ions from very acidic solutions was demonstrated. In this paper we report on the uptake of various transition and post-transition metal ions with Diphonix and two other resins for comparison. The results show that Diphonix has a very high affinity for Fe(III) and Cr(III) in very acidic solutions. From neutral solutions Diphonix exhibits a high selectivity for lead and transition metals over calcium. Conditions for efficient stripping of the investigated ions have been found.     

UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 5 : THE EFFECT OF SOLUTION MATRIX ON ACTINIDES

ABSTRACT

The influence of commonly occurring matrix constituents on the uptake of representative actinides in the tri-, tetra-, and hexavalent oxidation states by a new chelating ion exchange resin, called Diphonix?, has been investigated. The effect of increasing concentrations of HF at three fixed HC1 concentrations on the retention of U(VI), Np(IV), and Am(III) was measured. All three actinides showed strong retention in HF even up to a concentration of 1 M The effect of sulfuric, oxalic and phosphoric acids at three fixed HNO₃ concentrations on the retention of Th(IV), U(VI), and Am(III) was also measured. Only when the concentration of the complexing acids was above 0.1 M was the retention of the actinides decreased significantly at 0.1 M HNO₃ The effect was much less pronounced at higher HNO₃ concentrations.

Sodium, calcium, aluminum and iron were selected to study the influence of cationic matrix constituents on the uptake of actinide ions by Diphonix. In the case of tetra- and hexavalent actinides (represented by Th and U, respectively) only the very highest concentrations of Fe(III) and Al(III) caused a significant decrease in the retention of the two higher valent actinides. On the other hand, Am(III) retention was significantly lowered by Al and Fe(III) concentrations above 10^?2 M The influence of Al and Fe(III) on the uptake of Am(III) may be minimized by use of fluoride ion to complex Al and by reducing Fe(III) to Fe(II). Macroconcentrations of sodium and calcium had only minimal influence on the uptake of actinides in all three oxidation states.     

UPTAKE OF METAL IONS BY A NEW CHELATING ION EXCHANGE RESIN. PART 8 : SIMULTANEOUS UPTAKE OF CATIONIC AND ANIONIC SPECIES* *

ABSTRACT

The uptake of tri-, tetra- and hexa-valent actinides as well as of pertechnetate anions by some new multifunctional ion exchange resins has been investigated. The new resins, identified as Diphonix A, for anionic Diphonix, contain the same geminally substituted diphosphonic acid groups bonded to a styrenic-based polymer matrix as the regular Diphonix resin, plus strong base anion exchange groups such as the tetraalkylammonium (Diphonix A - Type 1 resins) or the quaternized pyridinium (Diphonix A - Type 2 resins) groups. Our uptake measurements have shown that the Type 2 Diphonix A resins are as effective as the regular Diphonix resin in the rapid uptake of actinides from acidic solutions, while at the same time sorbing pertechnetate anions in a manner comparable to existing commercial anion exchange resins. The failure of the Type 1 Diphonix A resins to perform equally well has been explained as a consequence of the mutual interaction of adjacent diphosphonic acid groups and tetraalkylammonium groups. Uptake data have also been obtained with Se(IV). The behavior of the Diphonix A resins toward Se(IV) uptake in acidic solutions is comparable to that of commercial anion exchange resins.     

UPTAKE OF METAL IONS BY A NEW CHELATING ION EXCHANGE RESIN. PART 3: PROTONATION CONSTANTS VIA POTENTIOMETRIC TITRATION AND SOLID STATE 31P NMR SPECTROSCOPY

Abstract

A new chelating ion exchange resin which incorporates methylenediphosphonate, carboxylate, and sulfonate functional groups in a polystyrene-divinylbenzene matrix has been prepared. This resin exhibits exceptionally high affinity for polyvalent cations even from moderately acidic aqueous media. Metal ion coordination occurs primarily at the diphosphonate group with the secondary binding sites contributing to charge neutralization when necessary and possible, and to increasing hydrophilicity of the resin pores. In the present investigation, the protonation equilibria of the phosphonate groups in the resin are investigated via potentiometric titration and solid-state ³¹P NMR spectroscopy of the resin. Intrinsic equilibrium constants for the first two diphosphonate protonation reactions are pk₄7equal; 10.47 and pK₃ = 7.24. The last two protons added to the diphosphonate group are acidic having pK_a values less than 2.5. These protonation constants are consistent with those reported previously for monomer analog 1,1-diphosphonic acids. This result implies that thermodynamic data available in the literature can be used to predict the relative affinity of the resin for polyvalent cations.     

螯合树脂吸附金属阳离子的应用及其研究进展

螯合树脂是一类能与金属离子形成多配位络合物的交联功能高分子材料,在处理废水中金属离子的应用十分广泛。介绍了5种不同的螯合树脂分类方法,综述了含有不同官能基团的螯合树脂应用于吸附重金属阳离子的研究现状,并分析讨论了国内常用的螯合树脂及优缺点,进而提出未来螯合树脂用于去除金属阳离子的研究重点。     

新型螯合纤维对重金属离子吸附性能的研究

本文研究了由聚(N-乙烯基甲酰胺／丙烯腈)水解得到的一种新型螫合纤维的合成、结构特征和螯合性能。这种纤维包含了高密度的螯合基像脒基、氰基和酰胺基等。研究结果显示了该纤维对金属离子有很高的束缚能力，对Cu^2 ，Cr^3 ，CO^2 和Ni^2 的最大吸附量分别为108．46，87．03，137．68和105．06mg／g。吸附在螫合纤维上的金属离子经洗脱后可回收，螯合纤维可以反复使用。     

SWELLING OF A CHELATING MACROPOROUS RESIN DURING METAL ION EXCHANGE

ABSTRACT

The kinetics of heavy metal ion exchange onto a commercial chelating resin was investigated from the standpoint of the swelling-shrinking experienced by the resin bead during the overall ion exchange process. Temporal measurements of the volume variations were carried out for every step of an operational cycle, metal load, elution and regeneration of the ion exchanger, using a microreactor mainly composed by a reaction cell, an optical microscope and an image treatment system. Experimental results were properly fitted to an empirical equation, whose parameters were used to characterize and compare different systems. A pseudosteady state kinetic model, which takes into account the volume variations of the resin bead during the ion exchange reaction, fits fairly well to experimental results, and was used to obtain the effective diffusion coefficients of the metals through the macroporous matrix. Finally, the study of the batch ion exchange kinetics of transition metal cations was completed with a potentiometric titration and other equilibrium determinations. These results were compared with those derived from swelling measurements.     

改性大豆蛋白凝胶对金属离子螯合能力的研究

用乙二胺四乙酸二酐（EDTAD）对大豆蛋白进行酰化改性,再用戊二醛交联制得凝胶,研究了凝胶对Pb^2＋、Zn^2＋、Cu^2＋、Ca^2＋的螯合能力,探讨了离子浓度、温度、pH值和改性程度对凝胶金属螯合能力的影响。凝胶对Ca^2＋、Zn^2＋、Pb^2＋、Cu^2＋的最大螯合分别为0．71、0．65、0．75、0．58mmol/g。结果表明,该凝胶具有作为金属螯合剂应用于污水处理中的可能性。     

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS. XLVIII. ION-EXCHANGE REACTION OF ALKALI METAL IONS/H+ ON MONOCLINIC ANTIMONIC ACID

The pH titration curves of monoclinic antimonic acid (M-SbA) showed apparently monobasic acid for the systems of alkali metal ions/H⁺. The uptake order of the metal ions were K⁺ < Rb⁺ < Cs⁺ < Na⁺ < Li⁺ throughout the pH range studied. The low uptakes of K⁺, Rb⁺, Na⁺ and Cs⁺ at high pH might be due to steric or ion sieve effects for large unhydrated cations on M-SbA. Thermodynamic data were derived for Li⁺/H⁺ exchange on M-SbA from pH titration curve.     

生物法去除水中重金属离子的研究

微生物去除水中的重金属离子是微生物利用一个新的研究领域,微生物的这种性质在处理含有重金属离子的废水溶液中具有广阔的应用前景。本文对微生物去除重金属离子的原理,去除过程中的影响因素：溶液pH值、重金属离子的初始浓度、生物去除剂的预处理、去除时间、去除温度以及重金属离子的回收和重复使用等作了详细的综述。     

ION-EXCHANGE SELECTIVITY FOR ALKALI METAL IONS ON A CRYPTOMELANE-TYPE HYDROUS MANGANESE DIOXIDE

ABSTRACT

A cryptomelane-type hydrous manganese dioxide in the H⁺ form has been studied for its ion-exchange selectivity for Li+, Na+, K+, Rb+ and Cs+/H+ exchange at 30*C. The distribution coefficients for each alkali cation were calculated as a function of the initial concentration of exchanging cations in the presence of a constant total normality of 0.1 N. The separation factor for the Na+ - K+ pair attained 1.3 x 10" at X_x→0 This extremely high selectivity can be attributed to the rigid tunnel structure with an opening which is only accessible to less hydrated cations, those that shed their hydration shell easily and those with crystal ionic radius of approximately 1.4A.     

重金属的超临界络合萃取动力学

引　言超临界ＣＯ2 络合萃取是去除重金属的一种清洁高效的方法 .其原理是利用络合剂与带电的离子通过配位键生成电中性的、弱极性的、稳定的、易溶于超临界ＣＯ2 的络合物 ,从而可被超临界ＣＯ2萃取[1] .该技术具有萃取速度快、萃取率高、萃取温度较低、生物兼容性好和无毒、无污染等优点 .近年来 ,对土壤、河床污泥以及从模拟的滤纸和砂土上萃取金属离子的研究 ,国外已有大量报道[2 ] ,但从真实体系中萃取痕量重金属的报道则很少[3] .中药以其丰富的资源、独特的疗效、毒副作用小等优点已引起了世界各国的关注 .然而 ,由于环境污染、炮制…     

ACID/BASE AND METAL UPTAKE PROPERTIES OF CHELATING AND WEAK BASE RESINS

Purolite's weakly basic experimental resins with diethanolamine, morpholine, 2-vinylpyridine, mono-and bispicolylamine functionalities were evaluated with respect to their hydrogen, Zn, Ni, Cu and Cd uptake, and compared with Purolite's commercial chelating iminodiacetate, aminophosphonate and hydroxamic acid resins. Special attention was paid to the resin performances in acidic solutions. In general, diethanolamine, morpholine and 2-vinylpyridine resins took up these metals poorly. Only cadmium was retained in acidic solutions, probably as negatively charged chloride complexes. The chelating resins, with their weakly acidic groups, did not function in acidic solutions but worked well at pH 4 and above. The only resin that efficiently removed metals from acidic solutions was the bispicolylamine resin. Metal uptake values on this resin did not change appreciably in the pH range between 1 and 6. Maximum uptake values ranged between 0.6 and 1.7 mmol/g, being highest for copper and lowest for nickel. Acid/base properties of the weakly basic resins did not correlate with their capability to take up metals from solution: the results obtained did not support the initial assumption that the weaker the resins are the better they take up metals in acidic solutions.     

用DTA研究环氧树脂固化反应动力学

本文用DTA和FIR研究双酚A二缩水甘油醚型环氧树脂与2-乙基-4-甲基咪唑固化反应动力学,探讨了固化反应的机理。结果表明,此固化反应是分步进行的。第一步是加成反应,第二步是催化聚合反应,由此确定适宜采用分段固化工艺。通过DTA曲线推得固化工艺温度,并计算固化反应各步活化能：E1＝36．8kJ．mol-1,E2＝53．gkJ·mol-1。     

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS. XXXXI. ION EXCHANGE EQUILIBRIA OF ALKALI METAL IONS/HYDROGEN IONS ON TIN(IV) ANTIMONATE

Ion exchange equilibria of alkali metal ions (Li⁺, Na⁺, K⁺,, Rb⁺, and Cs⁺)H⁺, systems have been studied in MNO-j-HNOj media with ionic strength of 0.1 at 30, 45 and 60 °C on tin(IV) antimonate as a cation exchanger. The ion exchange isotherms have been measured for both forward and backward reactions by the batch technique. The isotherms showed S-shaped curves for all exchange systems studied. The selectivity coefficients (logarithmic scale) vary with the equivalent fraction X_M of alkali metal ions in the exchanger and give two linear functions of X_M with a break point (X_M= 0.14, except 0.04 for Li⁺, /H⁺) indicating two different exchanging sites. The selectivity sequence, Na⁺, ? K⁺, ? Rb⁺, ? Cs⁺, ? ? Li, holds in the range of Xu= (0 - 0.04) and the sequence, Cs < Rb ⁺, ? K ⁺, ? Na ⁺, < Li ⁺, applies when X_M is higher than 0.14.

Hypothetical thermodynamic data on “zero loading” of the ion exchange reaction was evaluated.     

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS XXXVI. SYNTHESIS OF CRYPTOMELANE-TYPE HYDROUS MANGANESE DIOXIDE AS AN ION-EXCHANGE MATERIAL AND THEIR ION-EXCHANGE SELECTIVITIES TOWARDS ALKALI AND ALKALINE EARTH METAL IONS

Abstract

Hydrous manganese dioxide in a cryptomelane-type showed an excellent ion-exchange selectivity for K⁺, Rb⁺and Ba²⁺ ions having the effective ionic radii of about 1.4 Å. Log-log plots of distribution coefficients for alkali and alkaline earth metal ions vs. [HNO₃] yielded a straight line with a slope of ?1 and ?2, respectively, indicating the “ideal” ion-exchange mechanism. The stoichiometry of ion-exchange reactions was also established for the uptake of macro-amounts of alkali metal ions in nitrate media.     

PPO改性线性酚醛树脂的热降解动力学研究

以聚苯醚(PPO)改性线性酚醛树脂.采用热重分析法研究了不同升温速率下PPO改性酚醛树脂的热降解过程,通过非模型拟合法中的Flynn-Wall-Ozawa法、Friedman法和Kissinger法计算了降解过程的热降解活化能.结果表明,该树脂的热降解活化能随转化率的提高呈现先升高后降低再升高的态势,转化率为10%时,...     

EVALUATION OF A DIETHANOLAMINE CHELATING RESIN USING TWO-PHASE POTENTIOMETRY

ABSTRACT

The synthesis of a polystyrene resin functionalised with diethanolamine is described. Protonation of the resin and complexation of Pb(II), Cd(II), Hg(II), UO₂ ²⁺, Fe(III), Ca(n) and Nd(III) were studied using two-phase potentiometry. From these experiments, apparent formation constants could be calculated and distribution curves obtained. Predictions as to metal ion separations were then possible. Batch experiments with Eu(III) and Pu(IV) were also performed as well as a column experiment for Pb(II) and Ca(II) to test selectivity. The resin shows selectivity towards metal ions that are large and/or have a good affinity for nitrogen donor ligands. Metal ions susceptible to hydrolysis are well complexed by the resin due to its ability to suppress hydrolysis.     

FTIR法研究芳胺固化双酚S环氧树脂反应动力学

用傅里叶红外光谱 (FTIR)法研究了几种芳香二胺在恒温下分别固化双酚 S环氧树脂(BPSER)的固化反应动力学 ,得出了各固化反应的表观活化能