Organic Ion Exchange Research Articles

TITRATIONS OF ORGANIC SOILS WITH STANDARD BASE: SOLUBILITY OF IONIZABLE FUNCTIONAL GROUPS AT 25 °C

The conversion of undissolved acidic functional groups into dissolved carboxylate anions has been monitored during potentiometric titration of a Typic Mesisol Peat at 25 °C. The analytical chemical calculations of total acid functional groups and of H+ dissociation equilibrium functions take the dissolution process into account. With 0.05 g of sample suspended in 20 mL of 0.1 N NaCl, the molarity of carboxylate anions in the external solution ranged from 4.3 × 10−4 M at 1 mL g−1 0.1 N NaOH, to 1.5 × 10−3 M at 6 mL g−1 0.1 N NaOH. The corresponding amounts of undissolved carboxyl groups were 5.2 × 10−4 and 1.0 × 10−4 mol g−1. Differential acid constants (KGA) for the undissolved carboxyls were 7.6 × 10−4 (σ 1.4 × 10−4) for αG < 0.02 (0.016 – 0.02) and 1.4 × 10−5 (σ 0.04 × 10−5) for αG > 0.026 (0.026 – 0.60). A substantial increase in productivity was achieved by means of an automatic titrator and a microcomputer with spreadsheet software. Types of data production and processing that were previously labor intensive have now become much more practical. Key words: Organic soils, organic matter solubility, organic soil carboxyls, organic soil ion exchange, organic soil titration, pH dependent solubility

Histamine selective microelectrode based on a synthetic organic liquid ion exchanger

A two-barrel organic ion-sensitive microelectrode has been developed to electrochemically detect histamine activity. The synthesis of the histaminesensitive liquid ion exchanger, composed of tetrafluorophenylboron histamine plus 3-nitro- o-xylol, and the construction of the two-barrel microelectrode (0.1–0.5 μm tip diameter) sensitive to histamine based on such an exchanger is reported. The calibration curves, their slope, selectivity, stability and detection limits for different solutions are described. High selectivity for Na +, K +, Ca 2+ was observed.

81Rb/Na separation for the production of a 81Rb/ 81mKr generator

When 81Rb is produced by α-bombardment of NaBr cyclotron targets, the presence of the large amount of Na prevents the preparation of an efficient 81Rb/ 81mKr generator for perfusion studies. A quick, efficient 81Rb/Na separation method has been developed. It entails the sorption of 81Rb by ammonium molybdophosphate (AMP) from a 81Rb/NaBr solution, dissolution of the AMP with NH 4OH, addition of triethanolamine (TEA) and evaporation of NH 3. 81Rb is then sorbed on a macroporous organic ion exchange resin and TEA is selectively eluted with HCl. Various characteristics of the generator prepared in this way have been measured.

Organic ion exchange of ZSM-5 zeolite

The ion-exchange properties of organic substituted ammonium cations in ZSM-5 ion exchange were found to be considerably different from those of inorganic cations. All the organic ions studied have exceptionally high selectivities. Full-capacity exchange is readily attained except for those cations unable to penetrate the ZSM-5 pore opening because of ionic size. The selectivity sequence of these organic ions in ZSM-5 exchange is reversed from that of high-alumina zeolites and has been explained in terms of the reduced electric field strength within the framework of ZSM-5.

Continuous water purification system for Langmuir film studies

A system for continuous purification of water to make it suitable for use in Langmuir film studies has been designed and implemented in our laboratory. The system incorporates particulate filtration, activated carbon adsorption, deionization by reverse osmosis, and continuous distillation under a nitrogen sweep. Surface tension in excess of 99% of theoretical and resistivity of 18 Megohm-cm at 25°C have been achieved without the use of organic ion exchange resins.

The use of neutron activation in dietary reference material analysis

Results for a number of trace elements in a total human diet material (USDIET-1), obtained by the application of both INAA and RNAA are presented. Several dietary reference materials such as NBS SRM 1577A, and BCR CRM Single Cell Protein were also analyzed, and these results are also given. Combining measurements on short and long lived radionuclides, the INAA approach is useful for the determination of about 20 elements. In order to expand the elemental coverage or improve detection limits, RNAA was also explored in two modes: separation of radionuclides using organic ion exchange resins and the use of hydrated manganese dioxide. This combination is applicable to 15 trace elements. For example, using RNAA, the following results were obtained for USDIET-1: Cd=31.8, Mo=280, Cr=71, Ag=4, As=117 and Sb=9.4 μg/kg. In the INAA mode, special attention was given to Al, F and Se. The F content of USDIET-1 was found to be 840 mg/kg, a rather high value, resulting from handling USDIET-1 by Teflon tools. By applying INAA and RNAA under two different laboratory conditions, it has been demonstrated that, even for the so-called difficult to determine elements like Cr, As or Mo, consistent results can be obtained. Thus, NAA promises to be a strong tool for human nutritional studies.

Hydration of 2-methylbutenes on organic ion exchange resin catalysts

The course of the hydration of a mixture of 2-methyl-1-butene and 2-methyl-2-butene in dependence on the structure of strongly acidic styrene-divinylbenzene ion exchange resin catalysts has been studied. The most efficient catalysts turned out to be macroporous ones. The reaction rate increased with increasing temperature, while the amount of the product (2-methyl-2-butanol) in the equilibrium reaction mixture decreased. Similarly, the hydration was strongly affected by the water to alkene molar ratio in the starting reaction mixture. Modification of ion exchange resin catalysts with 1-butylamine did not affect course of the hydration in the case of gel type catalysts, while with macroporous resin catalysts the addition of amine up to 0.5% of the total catalyst exchange capacity showed activating effect.

A review of the radiation stability of ion exchange materials

A comprehensive literature survey on the radiation stability of ion exchangers resulted in the publication of an extensive data compilation on the effects of ionizing radiation on synthetic organic ion exchangers in this journal (Vol. 97, No. 1). This paper is a brief review of the majorfindings of this literature survey along with similar information on synthetic inorganic ion exchangers. The primary goal of this literature survey is to review present knowledge on the effects of ionizing radiations on synthetic ion exchange materials used in radiochemical processing. Although there are gaps in our knowledge of the mechanisms of radiolytic changes in ion exchangers, the information available in the literature shows some general trends and similarities in observed qualitative effects by different types of organic and inorganic ion exchange materials. These trends and observations have been formulated into a set of qualitative and semi-quantitative statements that can be useful to potential users of ion exchange materials in nuclear material processing and radioactive waste management. Present knowledge, of the behavior of ion exchangers under the influence of ionizing radiations is too limited to justify quantitative predictive modeling.

The effects of ionizing radiations on synthetic organic ion exchangers

Effects of ionizing radiations on organic ion exchangers are recognized as a vexing problem in the processing of special nuclear materials and high specific activity radioactive waste forms. An extensive literature survey, started in 1976 and updated periodically, indicates that radiation decomposition of ion exchange materials has the potential for a variety of undesirable consequences. It is also apparent from this survey that systematic efforts to identify and resolve these problems and to develop radiation resistant ion exchangers are extremely limited. There is, however, widely scattered information in the literature that is useful in designing and operating ion-exchange-based process systems with reasonable assurance of safety. The compilation of experimental data presented in this paper can contribute to better design and safer operations of synthetic organic ion exchange systems at nuclear material processing facilities.

A new method of plutonium speciation in sea water

A new method of plutonium speciation in large volume of sea water was developed by using adsorption of Pu(IV)-Xylenol Orange chelate and Pu-Arsenazo chelate on XAD-2 resin, respectively. The tetravalent plutonium ion reacts selectively with Xylenol Orange in acid solution and that adsorbed on XAD-2 resin. Total plutonium can be collected onto the resin in the form of its Arsenazo-III complex. The determination of plutonium then was carried out by alpha-ray spectrometric method after decomposition of organic complexes and ion exchange separation. The present method is confirmed for convenient and rapid preconcentration procedure for plutonium shipboard chemistry.

4401591 Treatment of organic ion exchange material containing radioactive waste products : Mila Korostenski, Vsweded assigned to ASEA Aktiebolag

4401591 Treatment of organic ion exchange material containing radioactive waste products : Mila Korostenski, Vsweded assigned to ASEA Aktiebolag

京都大学原子炉実験所の放射性廃水処理装置による除染実績と評価

Decontamination properties of radioactive liquid waste treatment facilities were studied from the data of radioactive concentration measured before and after the treatment.Evaporation treatment showed an excellent decontamination property, and every radioactivity of total α, total βγ and five important nuclides was not detected after this treatment.By chemical coagulation, total a radioactivity was effectively removed, but total βγ radioactivity was not. The DFs for total βγ radioactivity distributed between one and ten according to the nuclides contained in liquid waste. DF values of about ten were obtained for 60Co, 65Zn and 54Mn, and 137Cs was almost not removed. The removal of 51Cr lay between these two cases.The treatment using organic ion exchange resin (Na+ form) removed every nuclides except 137Cs, but was not sufficiently effective for 137Cs. When 137Cs exists in liquid waste, it is necessary to use a vermiculite column after the treatment of chemical coagulation and/or ion exchange.

Role of adsorbents in the separation of recoil 56Mn products of permanganates

The distribution of radioactive manganese formed by (n,γ) reaction in crystalline KMnO 4 has been followed using different inorganic and organic ion exchangers. Between Mn 2+ and MnO 2 states it varied when KMnO 4 was heated near its decomposition temperature. This has been attributed to the formation of colloidal MnO 2 during dissolution of decomposed permanganate and its flocculation, the extent of which depended upon the nature of the absorbent. 56MnO 4 − fraction was much higher for irradiation of concentrated solutions of different permanganate systems (1–10 −1 M) than for irradiation of solids. This fraction decreased to a limiting value of ∼ 4% upon dilution. A continuous extraction of the recoil species before their recombination could be achieved by neutron activation of quasi solutions containing either alumina or a polystyrene cation exchanger.

Organic ion exchangers with enhanced catalytic activity

Several methods aimed at increasing the catalytic activity of the sulphonated styrene-divinylbenzene macroporous ion exchanger Wofatit OK 80 have been tested. The activity of the prepared ion exchanger catalysts has been examined in three reactions of different type which allowed to examine the effect of the methods used in the broader range of conditions. The results obtained show that the catalytic activity of ion exchangers can be increased substantially either by increasing the total number of acid functional groups, or, particularly, by such treatment which makes the maximal number of the present functional groups accessible to reaction components. However, by the chemical procedures used to enhance the activity, the ion exchangers acquire frequently also some properties which affect negatively their application as catalysts.

Correlation of 137Cs Release From Small-Scale to Large-Scale Cement Waste Forms

ABSTRACTA study correlating the leachability of 137 Cs from small-scale to large-scale cement forms was performed. The waste forms consisted of (a) organic ion exchange resins incorporated in Portland I cement, with a waste-to-cement ratio of 0.6 and a water-to-cement ratio of 0.4 (as free water) and (b) boric acid waste (12% solution) incorporated in Portland III cement, with a waste-to-cement ratio of 0.7. 137Cs was added to both waste types prior to solidification. The sample dimensions varied from 1 in. ×1 in. to 22 in. × 22 in. (diameter × height). Leach data extending over a period of 260 days were obtained using a modified IAEA leach test. A method based on semi-infinite plane source diffusion model was applied to interpret the leach data, which allows prediction of the amount of 137Cs leached from the forms as a function of leaching time and waste form dimensions. A reasonably good agreement between the experimental and calculated data was obtained for both types of cement waste forms.

Supernatant Treatment Considerations for the Neutralized Waste at West Valley

ABSTRACTThe neutralized high-level waste, stored at the Western New York Nuclear Service Center in West Valley, New York, was produced during the operation of the Nuclear Fuel Service, Inc. commercial nuclear fuel reprocessing plant. The supernatant is a highly concentrated salt solution (NaNO3 , NaOH, Na2SO4 and NaCl) containing essentially all of the dissolved cesium as the primary radioactive component. The sludge is primarily iron and aluminum hydroxides and contains strontium and the bulk of the long-lived isotopes. The supernatant will be treated to remove essentially all of the radioactivity and then be concentrated and disposed of as low level nuclear waste. The following supernatant treatment considerations have been evaluated on a laboratory scale using simulated West Valley waste: 1) Organic ion exchange resins; 2) Inorganic ion exchange media; 3) In-tank processing. These processes will be described and preliminary laboratory data will be presented.

Distribution and catalytic activity of sulfonic acid groups in organic ion exchangers

AbstractThe existence of inhomogeneities in the polymer structure of ion exchangers was demonstrated and their influence on catalytic properties was shown. The results are based on the differences in catalytic activity of two ion exchangers with low degrees of sulfonation differing in the distribution of active groups within the polymer particles.

Crystalline insoluble acid salts of tetravalent metals—XXXIII: Investigations on the unusual initial shape of the titration curves of layered exchangers of the α-zirconium phosphate type

Several titration curves of crystalline acid salts of tetravalent metals show an evident decrease in the pH of the supernatant solution with an increasing addition of metal hydroxide. This phenomenon, very unusual for common organic ion-exchangers, seems to be quite general for inorganic ion-exchangers with layered structure of α-type. In order to throw light on this phenomenon, a detailed investigation was carried out on the titration curves of α- Zr(HPO 4) 2·H 2O with various metal hydroxides, particularly KOH. To obtain the presence of a distinct minimum in the titration curve, three conditions seem to be necessary: (1) high activation energy for H + M z+ exchange (which, in turn, depends on the relative size of M Z+ and size of the windows connecting the cavities (2) formation of solid solution having high M-content and (3) formation of a phase, with a large inter-layer distance, in the external parts of the crystals. This last point is particularly important since the enlargement of the external part of the crystals lowers the activation energy for the exchange of large cations. Thus, once started, the exchange can take place at lower pH′ values.

Organische und anorganische Ionenaustauscher zur heterogen katalysierten Alkylierung von Aromaten

AbstractOrganic and inorganic ion exchangers as catalysts for the heterogeneous alkylation of aromatics. Ion exchangers has advantages over low molecular for use in industrial alkylation reactions. The reactivity and selectivity behaviour of the polymeric catalysts were found to be markedly influenced by the structure of the polymeric matrix as well as the type and number of the functional groups. In this connection many similarities between inorganic ion exchangers (zeolites) and organic ion exchange resins were detected.

New ion exchangers, preparation, properties and application

Organic ion exchangers are used for many years in laboratory and industry. They consist of a network or matrix carrying functional groups or anchor groups which are responsible for the ion exchange properties. The network may be an artificial one obtained from monomers by polytnerisation or copolyrnerisation or by polycondensation. Products of this kind are called resins. On the other hand natural macromolecules like cellulose may be used as matrices.