INTRAPARTICLE DIFFUSION-CONTROLLED KINETICS OF ADSORPTION OF PHENOL ON ION EXCHANGE RESINS

A multi-section method was proposed to describe the batch adsorption system under intraparticle diffusion-controlled kinetics with a nonlinear adsorption isotherm. The intraparticle diffusivity of phenol on the anion exchange resins determined by using the proposed method was compared with the values determined from D-K and modified D-K methods. It was found that the intraparticle diffusivity determined in this study was reasonable.     

TEMPERATURE EFFECT ON ION EXCHANGE SORPTION OF PHOSPHATE

Phosphate sorption on the strong basic anion exchanger Amberlite IRA-400 (Cl^? form) is studied as a function of temperature ( 25^°C–50^°C), at two initial pH values (5 and 9 ) in the concentration range 120–190 ppm. Chloride released/phosphate sorbed ratios increase with the increase both in temperature and pH and decrease with the increase in the concentration of solution. It is suggested that phosphate sorption takes place initially as HPO₄ ^2? followed by H₂PO₄ ^?. The data is explained with the help of a modified Langmuir and mass law action equations. Various thermodynamic parameters (ΔG^°,ΔH^° and ΔS^°) are presented. The differential isosteric heat of adsorption, is computed at different temperatures, showing the sorption of phosphate to be endothermic on the anion exchanger Amberlite IRA-400.     

REACTION KINETICS OF POLYSTYRENE-BASED PHOSPHINIC ACID ION EXCHANGE/REDOX RESINS WITH METAL IONS

ABSTRACT

The ion exchange/redox kinetics displayed by the phosphinic acid polymer with aqueous solutions of silver and mercury is presented as a function of reaction temperature (6° to 45° C) and solution pH (0 to 5). The network variables studied include the crosslink level and macroporosity. At each pH, increasing the temperature leads to a more rapid approach to equilibrium. The amount complexed at equilibrium is lowest at pH Q relative to the higher pH solutions due to increased H⁺ competition for ligating sites. Metal ion reduction, rather than ion exchange, is the dominant component at equilibrium. Matrix rigidity and macroporosity do not affect Ag(I) kinetics. The rate of Hg(II) sorption is much faster than for Ag(I). Macroporosity is an important variable with mercury: macroporous resins complex more than twice the amount found with gels at 15 minutes contact. It is proposed that Ag kinetics are limited by a slow redox reaction while the Hg kinetics are diffusion-limited due to a fast redox reaction. Differences in reactivity arise from the reaction stoichiometry     

ION EXCHANGE KINETICS OF DL-LYSINE MONOHYDROCHLORIDE ON AMBERLITE IRA-420

ABSTRACT

The ion exchange kinetics of DL-lysine monohydrochloride on Amberlite IRA-420 have been studied. Ionic diffusivity of hydroxyl anion, which is supposed to be equal to the interdiffusion coefficient, has been evaluated by fitting experimental kinetic data to a theoretical model based on the continuity equation of the CI" anion in solution filling the pores of the resin. Because of changes of both viscosity with ionic concentration and co-ion behavior in solution at high concentrations, a variation of ionic diffusivity of hydroxyl anion has been observed. In order to predict the dynamic behavior of fixed beds a simple mathematical model including both equilibrium isotherm and ionic diffusivity of hydroxyl anion has been developed. Likewise, resin regeneration using NaOH solutions has been investigated. The results show the feasibility of the procedure of purification and regeneration and they have been used to design a plant for the treatment of 50 Tm/yr of DL-lysine monohydrochloride.     

ION EXCHANGE BEHAVIOUR OF CHELATING RESIN DOWEX A-1WITH ACTINIDES AND LANTHANIDES

Adsorption studies of several actinides and lanthanides have been carried out by chelating ion exchange resin Dowex A-1. The metal ions studied were Pu⁴⁺, Zr⁴⁺, UO₂ ⁺⁺, Am³⁺, Cm³⁺, Bk³⁺, Cf³⁺, Eu³⁺, and Tm³⁺. The separation factors between consecutive trivalent actinides and between Am(III) and Eu(III) have been evaluated. Mechanism of adsorption of actinides and lanthanides from different aqueous media has been discussed. An ion exchange procedure for the separation of Pu⁴⁺ and UO₂ ⁺⁺ has been developed using this resin.     

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.     

树脂法再生贮氨材料包覆废液初探

阐述了贮氢材料包覆废液的特性。利用离子交换法进行处理，并探索了它的实际效果，为化学镍镀液的废水治理开拓了一条新的途径。     

THE EXTRACTION OF SILVER FROM CYANIDE SOLUTIONS WITH ION EXCHANGE RESINS

ABSTRACT

The ability of various ion exchange resins to extract silver from synthetic cyanide solutions was evaluated. It was found that weak base resins such as DUOLITE A-7, DOWEX WGR-2, DOWEX MWA-1, DOWEX XFS-4195, and AMBERLITE IRA-35 extract silver significantly only when the pH is lower than 8. At higher pH, the same resins exhibited little or no silver extraction. A comparison among weak base resins showed that DUOLITE A-7 and DOWEX MWA-1 have the best characteristics in terms of capacity and elution efficiency.

Strong base resins such as DOWEX MSA-1 and AMBERLITE IRA-910 extract silver in the entire pH range from 4 to 12. When the aqueous feed solution contains only one metal, these resins have a significantly larger capacity for silver than for copper, iron or zinc. But, if one or more base petals are added to the cyanide feed solution, the silver extraction is depressed to an extent which depends on the contact time. The silver extraction can be maximized by decreasing the concentration of free cyanide in the aqueous solution and by stopping the extraction before the resin attains the saturation point     

钨酚醛树脂固化反应动力学研究

以六亚甲基四胺为钨酚醛树脂的固化剂,采用差示扫描量热法(DSC)研究了该体系的固化过程,得到了钨酚醛树脂固化反应的表现动力学参数,它对树脂的固化工艺选择具有重要意义。     

KINETICS OF ZINC REMOVAL FROM COBALT ELECTROLYTES BY ION EXCHANGE

ABSTRACT

The removal of trace zinc concentrations from the INCO (Port Colborne) cobalt advance electrolyte by solvent impregnated ion exchange was studied in column and batch tests. The resins OC 1026, SIR 272 and SIR 302 were compared in terms of zinc loading and selectivity.

The OC 1026 resin demonstrated superior zinc loading and selectivity characteristics, but retained significant amounts of cobalt. Cobalt loading was determined to be closely related to the electrolyte pHdrop across the column. Resin pre-treatment with the advance electrolyte at pH 3 acts to diminish the pH drop across the column, and hence reduced the cobalt retained. Results from batch tests were fitted to kinetic models to gain an insight into process mechanisms. It was found that pre-treatment enhanced the apparent diffusion coefficient inside the resin phase by nearly an order of magnitude, improved exchange kinetics by allowing a lower pH reduction during the loading process, and improved Co²⁺/Zn²⁺ exchange in a matrix of the cobalt complex. Breakthrough curve analysis was also undertaken to determine the rate determining steps in the column process.

Further work is needed in X-ray microprobe analysis of resin samples from various portions of the column after loading, to gain a better understanding of the column loading process. The use of zinc selective electrodes in batch tests could also be undertaken to obtain more accurate estimates of diffusion and mass transfer coefficients.     

ION EXCHANGE BEHAVIOUR OF 23 ELEMENTS AND AMPHOTERIC PROPERTIES OF CHELATING RESIN DUOLITE ES 346 CONTAINING AMIDOXIME GROUPS

Distribution coefficients of 23 elements between chelating resin Duolite ES 346 containing amidoximo groups and glycine - HCl buffer /pH = 2 - 3.5/, acetate buffer /pH = 3.6 - 5.6/ and HCl solutions /0.05 - 12M/ respectively were measured by batch equilibration at tracer loadings. While alkali and alkaline earth metals are practically not retained by the resin, transition and other metal ions show quite differentiated pattern of selectivity. The resin exhibits amphoteric properties and in certain conditions both cations and anions can be simultaneously adsorbed. Selectivity reversal for some pairs of metal ions can be achieved employing either cation exchange or anion exchange function of Duolite ES 346. Quantitative separations of Zn-Fe, Cd-In, Zn-Hg, Co-Cu, Zn-Re-Ga and Pt-Pd mixtures with the use of short columns of the resin have been demonstrated.     

EFFECTIVE DIFFUSION COEFFICIENTS OF COPPER IN MACROPOROUS CHELATING ION EXCHANGE RESIN D751

Kinetic data on the macroporous chelating ion exchange resin D751 containing iminodiacetic acid as ligand are presented. The experimental systems are R-Na / Cu(N0₃)₂, R₂Cu/HNO₃and R-(Na+H) / Cu(NO₃)₂. Sorption and desorption rates of copper were measured in batch experiments by using a three-necked flask as the reaction vessel. The effective diffusion coefficients of copper have been calculated.     

离子交换对硼硅酸盐平板玻璃表面组成及性能的影响

研究用低温离子交换法增强硼硅酸盐平板玻璃.以熔融KNO3作为离子交换源,分别加入少量KOH,KF和锑酸钾(K2H2Sb2O72H2O)添加剂,在玻璃转变温度以下对硼硅酸盐平板玻璃进行K -Na 离子交换处理.利用电子探针研究了离子交换前后玻璃的表面组成变化;测定了样品的显微硬度、抗折强度和透过率.研究了添加剂种类与玻璃抗折强度之间的关系.研究结果表明:经K -Na 离子交换处理后硼硅酸盐玻璃表面K 浓度增加,交换深度可达30μm.经K -Na 离子交换后硼硅酸盐平板玻璃的强度提高,其抗折强度约为交换前的3倍.     

熔盐添加剂对玻璃离子交换和增强的影响

在工业纯KNO3中分别添加KOH,K3PO4,K2CO3,K2SiO3与Al2O3的混合物,研究了熔盐添加剂对浮法玻璃离子交换和增强的影响.用电子探针测试了玻璃表而的K+浓度;测定了样品的表面应力、弯曲强度和显微硬度.结果表明:上述添加剂町以增加离了交换层深度,缩短离子交换时间,明显提高玻璃的力学性能,其增强效果与分析纯KNO3的增强效果相当,甚至比后者好:在交换温度为450℃下,玻璃交换层厚度大于29μm,玻璃的力学性能为:表面应力>480MPa,弯曲强度>400MPa.显微硬度为6.49GPa.     

两种呋喃树脂热解过程中动力学初探

以聚糠醇（ＰＦＡ）和聚糠酮（ＰＦＫ）两种呋喃树脂为原料进行热解制备了玻璃炭（ＧＣ）的前驱体,研究了前驱体在２５０～６５０ ℃下热解反应的动力学参数,得出了热解过程中的Ａｒｒｈｅｎｉｕｓ 方程分别为ｋ＝ ６８．０３ｅｘｐ （－２６．５１×１０３／ＲＴ）（ＰＦＡ）和ｋ＝３２．７９ｅｘｐ（－２１．３０×１０３／ＲＴ） （ＰＦＫ）。     

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.     

漏钠对除盐离子交换的影响及防止

“漏Ｎａ”将导致一级除协水电导率升高和影响阴床出水中ＨＳｉＯ３含量的升高。本文讨论了“漏Ｎａ”产生的原因和防止方法。     

FDP与树脂之间交换速度控制因素

用弱碱性阴离子交换树脂研究了ＦＤＰＣｌ离子相互交换作用的动力学关系及有关过程的速率控制步骤并计算了颗粒扩散系数。实验发现,当溶液的质量浓度在１０ｇ／Ｌ以上时,ＦＤＰ与树脂之间的交换速率主要受颗粒扩散控制,当溶液的质量浓度≤１０ｇ／Ｌ时,ＦＤＰ与树脂之间的交换速率主要受液膜控制。     

SORPTION BEHAVIOR OF PERTECHNETATE ION ON REILLEXTM-HPQ ANION EXCHANGE RESIN FROM HANFORD AND MELTON VALLEY TANK WASTE SIMULANTS AND SODIUM HYDROXIDE/SODIUM NITRATE SOLUTIONS

ABSTRACT

The batch distribution coefficients (K_d, mL solution /g dry resin) for pertechnetate (TcO₄) between Reillex^TMHPQ anion exchange resin and various caustic solutions have been determined. The average K_d value in 1.5 M NaNO₃/l.0 M NaOH solution is (262.2 ± 12.6) mL7sol;g for TcO₄ ^? ranging from 1.0 × 10^TM M to 5.0 × 10^?4 M. Pertechnetate K_d values were measured in a series of NaOH7sol;NaNO₃ solutions. The series are: 1.00 M NaOH with 0.010 to 5.00 M NaNO₃; 0.100 M NaOH with 0,010 to 5.00 M NaNO₃; 0.100 MNaNO₃ with 0.10 to 5.00M NaOH; 1.00MNaNO₃ with 0.10 to 5.00 M NaOH; 1.50 M NaNO₃ with 0.10 to 5.00 M NaOH; 3.50 M NaNO₃ With 0.10 to 5.00 M NaOH. The K_d values are described by the following equation.

This equation was used to predict the K_d values for a series of tank waste simulants. The predicted K_d values are different from the measured values with an average absolute difference of (29 ± 10)%.

Pertechnetate k_dvalues for 101-SY, 103-SY, DSS, DSSF-2.33, DSSF-5, DSSF7, 101-AW, and Melton Valley simulants have been determined as a function of time. A first order approach to equilibrium is observed. The K_d values at two hours are (1066±45), (870± 102), (346± 18), (296± 15), (245 ±6), (209± II), (218±5), and (167 ± 5) mL/g, respectively.