Strong Base Anion Exchange Resin Research Articles

Effects of pH and uranium concentration on the removal of uranium from drinking water by ion exchange

Effects of pH in the range of 5 to 8 and uranium concentration in the range of 0.02 mg/l to 25 mg/l on the removal of uranium with a strong base anion exchange resin (SBA) and a chelating aminophosphonate resin were studied. The results of the batch and column mode experiments clearly showed that the aminophosphonate resin was an efficient exchanger for the removal of uranium at pH values close to 5 and the SBA resin at higher pH values. In the column experiments, where altogether 2000 bed volumes of drinking water simulant were processed with these exchangers, the uptake of uranium was as high as 99.8% by the aminophosphonate resin at pH 5 and 99.7% by the SBA resin at pH 8.

Development of Bifunctional Anion-Exchange Resins with Improved Selectivity and Sorptive Kinetics for Pertechnetate: Batch-Equilibrium Experiments

A novel class of strong-base anion-exchange resins, bearing two different types of exchange sites, is described. These bifunctional resins have anion-exchange sites composed of two separate and differently sized trialkylammonium groups. In pertechnetate (TcO4-) uptake experiments from a solution matrix containing anions commonly encountered in groundwater, bifunctional resins containing exchange sites derived from tri-n-hexylamine in combination with either triethylamine, tri-n-propylamine, or tri-n-butylamine were shown to possess superior 24-h distribution ratios (Kd) for pertechnetate over all monofunctional anion-exchange resins (derived from a single trialkylamine) examined. For example, although monofunctional resins containing a tri-n-hexylammonium exchange site possessed excellent selectivity for pertechnetate over other anions, the exchange kinetics were poor. The superior performance of these resins can be attributed to the combination of a large trialkylammonium site for enhanced selectivity fo...

Removal of234,238U,226Ra,210Po and210Pb from drinking water by ion exchange

Six organic and five inorganic ion exchangers were studied for the removal of natural radionuclides from drinking water. In the first phase, distribution coefficients (KD) of uranium and radium were determined in three model solutions: a good quality water, an Fe-Mn-rich water and a saline water simulant. The exchangers showing highest KD´s for U and Ra were tested in column mode experiments for the removal of U,226Ra,210Po and210Pb from a real ground water. Considering the total 1800 processed bed volumes, the best decontamination factors (DF) for U, 20-120, were obtained with the strong base anion exchange resin. The most efficient exchangers for the removal of226Ra were the weak and strong cation resins and zeolite A. With use of long regeneration intervals, conventional organic resins are thus most suitable for the removal of radionuclides. When only a few hundred bed volumes were processed, with the corresponding regeneration interval about one week, the aminophosphonate resin was most effective for the removal of both uranium and radium.210Po and210Pb in ground water were mainly bound in particles and adsorbed on the surface of the anion resins. The use of the aminophosphonate resin to remove uranium and radium would therefore require an anion resin to take up polonium and lead.

The adsorption of precious metals and base metals on a quaternary ammonium group ion exchange resin

Adsorption tests were conducted with a quaternary ammonium group ion exchange resin to determine the equilibrium adsorption of precious- and base metals. The resin used is a macroreticular polystyrene type 1 strong base anion exchange resin. The adsorption was determined for synthetic single metal solutions as well as for multi-component solutions. The effect of the Cl − concentration on the equilibrium adsorption was determined for three different HCl concentrations, i. e. 6, 8 and 10%. The effect of chloride strength in the solution was also determined for mixed and base metal solutions. Pure metals, i.e. platinum, palladium and gold, were dissolved in aqua-regia and diluted to 2000 ppm (as metal) in 4M HCl. Ruthenium, rhodium and iridium were dissolved from pure salts in HCl. A 2000 ppm base-metal solution was prepared by dissolving all the required components, including precious metals, to match an in-plant industrial base-metals solution composition. For each precious metal the equilibrium adsorption was determined for typically two solution concentrations. Data points were established by varying the amount of resin added to the solution. The equilibrium concentrations were determined by ICP analysis after 24 hours exposure using the bottle-roll technique.

The Degradation of Strong Basic Anion Exchange Resins and Mixed-Bed Ion-Exchange Resins: Effect of Degradation Products on Radionuclide Speciation

The most important water-soluble products of the radiolytic degradation of anion exchange resins in a cementitious environment are ammonia and methylamines. These ligands do not form complexes with most radionuclides. Exceptions are Ni, Ag, and Pd, which form strong complexes with amines.Other degradation products of anion and mixed-bed ion-exchange resins are of no importance concerning the complexation of trivalent radionuclides. This is shown indirectly by adsorption experiments: The degradation products do not have a significant effect on the adsorption of Eu(III) on calcite.The effect of ammonia and methylamines on the complexation of Ni, Ag, and Pd is investigated by chemical modeling. For Ni and Ag, rather reliable predictions can be made using available thermodynamic data. In the case of Pd, large uncertainties are encountered due to unreliable data and gaps in the set of important species.The system Pd(II)-ammonia-water is explored in detail. Predominant species are inferred by chemical analogy, and their thermodynamic data are estimated. The uncertainty in these estimated and measured but unreliable data is bound by qualitative and quantitative chemical reasoning.

Simultaneous removal of cyanide and copper ions in a semi-fluidized ion exchanger bed

Simultaneous removal of cyanide and copper ions from electroplating wastewater was studied in a liquid-solid semi-fluidized ion exchanger bed. The diameter and the height of column are 20 mm and 600 mm, respectively. Strong-base anion exchange resin particles (Dowex 1X8-50) were contacted with synthetic solutions containing copper and cyanide ions. Cyanide and copper ions in the solution were analyzed by a cyanide electrode and ICP (inductively coupled plasma), respectively. The ion exchange equilibrium data of Cu+ removed as cyanide-copper complexes on Dowex 1X8-50 at 25 ‡C can be fitted with the Langmuir equation. Early leakage of cyanide from experimental loading profile data results in not only lower selectivity of free cyanide but also different selectivities of CN-Cu complexes due to the size and the structure of complexes. The optimum molar ratio (Q) between cyanide and copper ions is about 3 to obtain a reasonable removal rate of cyanide in this experiment.

Arsenic removal in fresh and nom-preloaded ion exchange packed bed adsorption reactors

Arsenic speciation and removal in continuous-flow packed bed adsorption reactors was investigated using a strong base anion exchange resin as the adsorbent. Preloading of the media was investigated passing arsenic-free Lake Washington water through columns packed with the resin prior to feeding influent spiked with arsenic. NOM preloading did not affect the systems, but sulfate adsorbed during the preloading and the subsequent adsorption steps caused chromatographic displacement of the adsorbed arsenic. Significant arsenic speciation changes occurred in the arsenic-spiked feeding solution that need further investigation.

Clean Ion-Exchange Technologies. I. Synthesis of Chlorine-Free Potassium Fertilizers by an Ion-Exchange Isothermal Supersaturation Technique

This paper reports the results of studying ion-exchange synthesis of chlorine-free potassium sulfate from KCl and Na2SO4 on strong acid cation-exchange and strong base anion-exchange resins using an ion-exchange isothermal supersaturation (IXISS) effect. This effect is observed for a number of ion-exchange systems, where the ion-exchange process is accompanied by the formation of a stable supersaturated solution of slightly or sparingly soluble substances in the interstitial space of ion-exchange columns. The formation of stable K2SO4 solutions in the columns has been observed by the displacement of either K+ or SO42- ions from a cation or anion exchanger with concentrated Na2SO4 or KCl solutions, respectively. After leaving the column, a supersaturated solution crystallizes spontaneously, which allows for the design of a practically ideal ion-exchange process where a crystalline chlorine-free potassium sulfate is obtained right after the ion-exchange conversion cycle. The process is practically wasteless...

Arsenic removal in fresh and nom-preloaded ion exchange packed bed adsorption reactors

Arsenic speciation and removal in continuous-flow packed bed adsorption reactors was Investigated using a strong base anion exchange resin as the adsorbent. Preloading of the media was investigated passing arsenic-free Lake Washington water through columns packed with the resin prior to feeding influent spiked with arsenic. NOM preloading did not affect the systems, but sulfate adsorbed during the preloading and the subsequent adsorption steps caused chromatographic displacement of the adsorbed arsenic. Significant arsenic speciation changes occurred in the arsenic-spiked feeding solution that need further investigation.

Disinfection of viable Pseudomonas stutzeri in ultrapure water with ion exchange resins

This study describes the disinfection of gram-negative bacteria, Pseudomonas stutzeri, isolated from ultrapure water (total organic carbon 5 ppb; effluent resistivity, > 18 MΩ cm at 25°C) with ion exchange resins using a batchwise procedure. A single bed of strong base anion exchange resin (SBAER) in OH − form shows disinfection ability; however, a bed of strong acid cation exchange resin (SACER) in H + form does not. Adsorption of bacteria on SBAERs occurs mainly due to the electrostatic attraction between positively charged SBAERs and negatively charged bacteria. In addition, hydrophilic interactions between SBAERs and bacteria are considered based on the results of adsorption isotherms. Since the positively charged SBAERs in Cl − form have no bactericidal effect, OH − ions are utilized for disinfection. Acrylic SBAERs in OH − form were more effective at disinfection than styrenic SBAERs. A mixed bed of SBAERs in OH − form and SACERs in H + form also disinfects bacteria more effectively.

Studies on ion exchange equilibria and kinetics VI. Prediction of ion exchange equilibria of UO 2 2+ −Na+−H+ ternary system

Experimental data are reported for the ion exchange equilibria of the binary systems UO 2 2+ −H+, UO 2 2+ −Na+ and Na+−H+, and of the ternary system UO 2 2+ −Na+−H+ on a strong acid cation exchange resin 001X7 at 25 °C. It is found that the equilibria for any pairs of ions are essentially the same in binary and ternary mixtures and that the prediction method proposed by our laboratory for SO 2 2− −Cl−−NO 3 − -201X7 strong base anion exchange resin system is also applicable to the ternary system studied in this paper. The predictions of the ternary system UO 2 2+ −Na+−H+ based solely on the binary data without using resin phase activity coefficients are consistent with the experimental data.

Retention of iron and chromium by an anion-exchange resin under decontamination conditions

The retention of iron and chromium ions on a strong base anion exchange resin (Lewatit M500 KR) in oxalic solution was studied by means of batch and column experiments. The tests performed indicate that more than 99% of the iron is uptaken by the resin, while chromium retention depends on the formation rate of the tri-oxalate complex. The experimental conditions required to improve chromium retention, such as temperature, pH, aging time, etc., were investigated and their consequences on the practical decontamination process are discussed. The available thermodynamic information for Fe(III) and Cr(III) oxalate complexes was reviewed and extended in order to determine the speciation in aqueous solutions in the range from 25 to 100°C. That information would help in searching for the optimal experimental conditions for ion exchange removal of these ions.

Gram-negative bacteria viable in ultrapure water: identification of bacteria isolated from ultrapure water and effect of temperature on their behavior

This study describes the effect of temperature on the behavior of bacteria viable in ultrapure water and the contamination of ultrapure water by bacteria. Three species of bacteria were isolated from ultrapure water (total organic carbon, 60 ppb and 5 ppb; effluent resistivity > 18 MΩ cm at 25°C) and identified by morphological and physiological characteristics. The three isolates were incubated in water for injection and PYG broth to check the growth profile at various temperatures. In PYG broth, temperature influenced the behavior of bacteria directly; however, it did not in water for injection. By checking both viable and non-viable bacterial numbers and endotoxin concentration in pure water, the water was found to be contaminated with non-viable bacteria and newly generated endotoxins besides viable bacteria. A column treatment, a mixed bed of fully regenerated strong acid cation exchange resin (SACER) and strong base anion exchange resin (SBAER), was used to remove bacteria from pure water. Bacteria could not grow on the surfaces of ion exchange resins in the mixed bed. The removal of bacteria was more effective as pure water was circulated through the mixed bed more rapidly.

Chromatographic behaviour of trace metal ions on a strong base anion exchange resin functionalized by azo ligands

A model which allows the evaluation of the elution volume V E and the central point V C of the breakthrough curve of a metal ion at trace level on a chromatographic column containing a chelating resin is presented. V E and V C mainly depend on the complexation properties of the active groups, and on the acidity and composition of the aqueous solution, according to the Gibbs-Donnan model for the resin. The model has been tested in the case of strong base anion exchange resins in chloride form functionalized with two different sulphonated azo ligands (T-azo-C, T-azo-R). The chromatographic behaviour of copper(II) and thorium(IV) is as expected from the formation of a complex with the azo dye in the resin, while that of zinc(II) and cadmium(II) is fully described by also taking into account the formation of anionic chloro complexes inside the resin.

Characteristics of boron adsorption on strong-base anion-exchange resin

The adsorption characteristics of boric acid on a strong-base anion-exchange resin, Amberlite IRN-78LC in OH − form, were investigated at 10, 30, 45 and 60°C in concentrations of boron up to 1500 ppm. The expression for the adsorption of boric acid is proposed as q=q ∞( K LC (1+K LC) +K cC+K 0 where q and q ∞ are the quantity of boron adsorbed on the resin and the ion exchange capacity of the resin, respectively, and C is the concentration of boron in solution. The K L introduced represents a Langmuir-type adsorption of boric acid in a low concentration of boron. K C can be interpreted as a so-called polymerization effect representing that borate ions with less boron atoms in the resin turn into polyborate ions with more boron atoms as the boron concentration in solution increases. In addition, K 0 represents the initial adsorption that takes place abruptly in the extremely low concentration of boron.

Etude de la regeneration de resines de denitratation par le chlorure de potassium

Abstract Increasing nitrate concentration in public water supplies required the use of specific treatments. In most cases, denitratation by ion exchange resin is prefered to biological processes. The main disadvantage of this process is the production of highly saline regeneration eluates ([Na+]=13–15 g.1‐1, [Cl‐]=13–15 g.1‐1, [NO3 ‐1]=10–15 g.1‐1, [SO4 2‐]=4–8 g.1‐1) which are generally discharged in rivers or in wastewater networks. Resin regeneration by potassium chloride instead of sodium chloride could allow the use of this eluates in agriculture. Experiments have been carried out on two strong base anion exchange resins (IMAC HP 555 and IMAC HP 441 from ROHM & HAAS) exhausted with water rich in nitrate or in nitrate and sulphate. Results show that KC1 regeneration leads to higher nitrate capacities than NaCl regeneration. Efficacity seems to be the same for sulphate removal.

Resin phase spectrophotometry of beryllium by an optical fiber and beryllon II

We have developed a resin phase spectrophotometric method to determine the amount of beryllium by detecting a change in absorbance of the resin phase. 8-Hydroxynaphthalene-3,6-disulphonic acid-(1-azo-2′)-1′,8′-dihydroxynaphthalene-3′,6′-disulphonic acid tetrasodium salt (beryllon II) immobilized by a strong base anion-exchange resin on the end of a bifurcated optical fiber bundle was chosen as a material sensitive to beryllium. Experiments were made using a home-made optical fiber spectrophotometer. The properties of the resin phase proved to be good for continual use of 350 times during a month. The reaction order between immobilized beryllon II and beryllium in solution was determined by kinetic theory and experiments. This method was also used to determine the amount of beryllium in beryllium—copper alloy; the response was linear from 0.43 to 2.60 μg/ml at pH 12.5 and 676 nm. The effect of interfering ions on the determination of beryllium was studied at the same time.

Batchwise separation of gallium by an anion exchange resin loaded with a sulphonated azo dye

Gallium(III) is sorbed by a strong base anion exchange resin loaded with a sulphonated azo-dye, T-azo-R [1-(tetrazolylazo)-2-hydroxynaphthalene-3,6-disulphonic acid], which is able to complex it in aqueous solution. As sorption takes place at acidities at which the hydrolysis of gallium is not negligible, it must be considered as conconmitant equilibrium. The distribution equilibria depend on the amount of ligand sorbed, and on the volume, acidity and ionic composition of the aqueous solution, according to the Gibbs-Donnan model. The thermodynamic complexation constant in the resin phase can be calculated from the experimental distribution coefficients; the value of log K = −1.24(0.20) is in acceptable agreement with that in aqueous solution [log K = −0.75(0.33)] which was also determined in the present investigation. Two equations deriving from the Gibbs-Donnan model are used for predicting the conditions for sorption and elution of gallium by a batch procedure, and for separating it from aluminium.

Comparison and modelling of the adsorption kinetics of gold cyanide onto activated carbon and resin in a silica slurry

The gold adsorption performance of two strong base anion exchange resins and a coconut-based activated carbon are compared. Isotherm experiments were performed which showed that the equilibrium loading of gold on resins is significantly higher than on carbon. It is also shown that the presence of silica slurries does not change the isotherm substantially.Batch kinetic experiments were performed at various rates of agitation and concentrations of solids. It is shown that the kinetics of gold adsorption onto the microporous resin Duolite A-161 is determined by film mass transfer until equilibrium loading is achieved. The presence of solids is shown to have little effect on the measured film-transfer coefficient.The kinetic results for the resin Minix are successfully modelled using the Homogeneous Solid Diffusion Model (HSDM), which incorporates film mass transfer and intraparticle diffusion. The presence of high concentrations of solids is shown to have a small inhibiting effect on the adsorption kinetics.The kinetic results for the activated carbon G210 show that the kinetics are successfully modelled by the HSDM for clear solutions and low solids concentrations. At high solids concentrations, a dramatic reduction in the adsorption rate is observed. This is ascribed to blocking of the carbon macropores by fine solid material. A modified HSDM is formulated in order to take into account this effect. This model allows for the outer shell of the carbon to be partially blinded by solid fines. This model is in good agreement with the experimental results. The results, therefore, indicate that strong base anion exchange resins are favoured over carbon in concentrated silica slurries from an equilibrium and kinetic point of view.

Chlorine leaching of gold-bearing sulphide concentrate and its calcine

In view of the environmental limitation imposed on cyanide disposal, there is general interest in developing non-toxic, safe substitutes for cyanide in the gold leaching process. Chlorine leaching, as a potential alternative to the conventional cyanidation for the extraction of gold, was tested on a sulphide concentrate and its calcine from the Pearl River Area, South China. The basic feasibility of using the resin-in-leach (RIL) technique in chlorine leaching of the gold-bearing sulphide concentrate and its calcine is discussed. The experimental results showed that, under optimal leaching conditions, the extraction of gold can be over 96%. The effect of various parameters on the extraction and elution of gold was also studied. The absorption of gold was over 99% with a strong base anion exchange resin. Gold can be eluted easily from the loaded resin with acidic thiourea solution at ambient temperature. Based on the experimental results from bench tests, a flowsheet for gold recovery from the sulphide concentrate is proposed.