Exchange Capacity Of Resin Research Articles

Influence of organic dispersant on nuclear grade anion exchange resin and their interaction behavior

ABSTRACT Polyacrylic acid (PAA) was used as an organic dispersant in the secondary circuit of nuclear power plants, which could interact with anion exchange resin and affect its properties in the condensate polishing treatment system. This study investigated the kinetics, isotherms, and thermodynamics characteristics of PAA adsorption on anion exchange resin. The results suggested that the inhibition of PAA adsorption on resin can be achieved by lowering the PAA concentration and temperature. In addition, the adsorption reversibility and influence of PAA on anion exchange resin were discussed. The chemical desorption agent (NaOH) can desorb 94.10% of the adsorbed PAA on resin. The physicochemical properties of anion exchange resin changed little after adsorbing and desorbing PAA. Furthermore, the interaction feature between PAA and anion exchange resin was revealed through analyzing the stoichiometry and ATR-FTIR spectra, which was partial ion exchange and most attachment. This feature caused the weak binding force between PAA and resin. Therefore, PAA was easily desorbed from the resin and the exchange capacity of resin can be restored after the chemical desorption process. In conclusion, PAA had little influence on the properties of anion exchange resin and did not cause nonreversible organic fouling.

Removal of Copper from Acid Mine Drainage (AMD) or Acid Rock Drainage (ARD)

Acid mine drainage is wastewater from a mine having a low pH and an elevated level of dissolved heavy metals. These metals are harmful to aquatic, animal and human life. This paper looks at the removal of copper from acid mine drainage using ion exchange to less than 1 mg/l. A weak acidic cation resin was used. Spectrophotometric determination of copper with sodium diethyldithiocarbamate was used to determine the copper concentrations in the treated water. Using regression analysis, the experimental results gave a correlation coefficient of 0.977 and a coefficient of determination of 99.5%. Results indicated that the higher the flows rate the shorter the period after which the copper concentration in the treated water reaches 1 mg/l. At pH 3.85 and 5.09, the resin performed better and at pH above 6.62 and between pH 3.0 and below the resin’s does not perform well. The higher the resin height the greater is the resin exchange capacity and the longer it takes for the copper concentration to reach 1 mg/l in the treated water. The higher the wastewater copper concentration the shorter the time it takes the resin to reach 1 mg/l. The results for this experiment indicated that acid mine drainage can be treated well by ion exchange resins, but it is also very important to establish suitable operating conditions.

Application of central composite design to reveal resin deterioration during the removal of hexavalent chromium from wastewater

ABSTRACT As a strong oxidant, aqueous Cr(VI) possibly oxidizes the polymer resin and weakens resin adsorption property during Cr(VI) removal from solutions by ion exchange. In the present study, to minimize the resin oxidation, central composite design approach based on response surface methodology was employed with different variables (Cr(VI) concentration of 100–1000 mg L–1, temperature of 293–333 K, pH of 1–7, and reaction time of 0–120 min) using a strong anionic resin (D202). The pH and reaction time had the most significant effect on resin oxidation, followed by Cr(VI) concentration. The temperature had a comparatively less significant effect on resin oxidation. The minimal Cr(VI) reduction efficiency (0.4%) was achieved with a Cr(VI) concentration of 251.5 mg L–1, temperature of 323.1 K, pH of 6.2 and reaction time of 52.5 min. Based upon a long-term operation and Fourier transform infrared rays analyses, the oxidation pathway of D202 resin was proposed. The rupture of the C–N bond led to the disappearance of the nitrogen-containing functional groups, which resulted in a significant decrease of resin exchange capacity.

Mechanism and kinetics study on removal of Iron from phosphoric acid by cation exchange resin

Abstract Iron element is one of the main impurities in wet-process phosphoric acid and it has a significant impact on the subsequent phosphorus chemical products. This paper studied the feasibility of using Sinco-430 cation exchange resin for iron removal from phosphoric acid. The specific surface area and the total exchange capacity of resin were 8.91 m2·g−1 and 5.18 mmol·g−1, respectively. The sorption mechanism was determined by FTIR and XPS and the results indicated that iron was combined with SO3H in resin. The removal process was studied as a function of temperature, H3PO4 content and mass ratio between resin and solution. The unit mass of resin to remove iron was 0.058 g·g−1 resin when the operating parameters were T = 50 °C, H3PO4 content = 27.61 wt% and S/L = 0.1, respectively. Kinetics study demonstrated that pseudo-second-order reaction model fits this study best and the calculated activation energy of overall reaction is 29.10 kJ·mol−1. The overall reaction process was mainly controlled by pore diffusion.

Preparation and characterization of Konjac glucomannan-based cation exchange resin

Abstract The granular Konjac glucomannan-based cation exchange resin with different pore diameters was synthesized by a low-cost way. The pore diameters could be controlled subtly by regulating the ratio of benign solvent (water) and expansion inhibitor (ethanol). The resin was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Its physical parameters were evaluated as well. The results indicated that the cross-linking reaction of Konjac glucomannan phosphate (KGMP) made the surface uneven and brought out a little fold-like structure that was beneficial to the water retention capacity and resin exchange capacity.

Application of Liquid Solid Semi-moving Bed to Fractionation of Cesium Ion in Wastewater

A liquid solid semi-moving bed with non-mechanical particle transport system is proposed and used for fractionation of cesium ion in wastewater. The particle transport system, which consists of a suction chamber, a mixing chamber, a nozzle and a riser tube, is designed to be controlled completely by hydraulic force. Experiments show that continuous feeding and discharging of resin can be realized by the transport system. The removal of cesium ion from wastewater is realized. The concentration of cesium ion in effluent liquid remains below 0.1g · L −1 (the initial concentration is 5.3g · L −1) during the 73 hours' experiment. The average exchange capacity of resin discharged from the bed is 0.57 mmol · (g dry resin) −1, which is close to the saturated capacity of 0.65 mmol · g −1. And it is also proved that the non-homogeneity of particle vertical velocity along the radial direction can seriously influence the ion-exchange process.

The study of various parameters affecting the ion exchange of Cu 2+, Zn 2+, Ni 2+, Cd 2+, and Pb 2+ from aqueous solution on Dowex 50W synthetic resin

A gel resin containing sulfonate groups (Dowex 50W) was investigated for its sorption properties towards copper, zinc, nickel, cadmium and lead metal ions. The use of selective ion exchange to recover metals from aqueous solution has been studied. The ion exchange behavior of five metals on Dowex 50W, depending on pH, temperature, and contact time and adsorbate amount was studied. Experimental measurements have been made on the batch sorption of toxic metals from aqueous solutions using cation exchanger Dowex 50W. The maximum recoveries (about 97%) Cu 2+, Zn 2+, Ni 2+, Cd 2+ and (about 80%) Pb 2+ were found at pH ranges 8–9. The amount of sorbed metal ion was calculated as 4.1, 4.6, 4.7, 4.8, and 4.7 mequiv./gram dry resin for Pb 2+, Cu 2+, Zn 2+, Cd 2+, and Ni 2+, respectively. The precision of the method was examined at under optimum conditions. Selectivity increased in the series: Pb > Cd > Cu > Zn > Ni. It has been observed that, selectivity of the –SO 3H group of the resin increases with atomic number, valance, degree of ionization of the exchanged metals. The equilibrium ion exchange capacity of resin for metal ions was measured and explored by using Freundlich and Langmuir isotherms. Langmuir type sorption isotherm was suitable for equilibrium studies.

Preparation of high capacity weak base poly(methyl methacrylate)-ethylene glycol dimethylacrylate copolymer anion exchange resin by modification using NOx

Macroporous poly(methyl methacrylate)–ethylene glycol dimethylacrylate (PMMA–EGDM) resin (resin 1) was prepared by suspension polymerization and gelatin was found to be the key component deciding the size of particles. To prepare aminated macroporous weak base PMMA–EGDM exchanger, resin 1 was nitrated using NO2 gas with a minor amount of NO (termed NOx). The modified PMMA–EGDM resin (resin 2) was reduced to NH2 groups and the exchange capacity of the weak base anion exchange resin (resin 3) was determined. Regression analysis of NOx consumption versus time and the exchange capacity Q versus time data suggested a second-order kinetics for the modification reaction and these are reported. We examined the effect of duration of nitration on the exchange capacity of resin 3. It was found that it first increased with the increase in the extent of nitration, reaching a broad maximum of 4.8 meq/g of wet resin with 78% moisture for about 8 h of nitration, and decreasing for longer nitration times as a result of polymer degradation. These results were compared with commercial resin, which had an exchange capacity of 1.68 meq/wet g with 43% moisture content. To assess the salvation ability of the modified PMMA–EGDM resin, consistent with the literature, we devised three stages of removing moisture. Experiments suggest that the high capacity of the modified PMMA–EGDM resin may be attributed to this increased salvation ability. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1991–1999, 2003

COMPARISON OF METHODS FOR NUTRIENT MEASUREMENT IN CALCAREOUS SOILS: ION-EXCHANGE RESIN BAG, CAPSULE, MEMBRANE, AND CHEMICAL EXTRACTIONS

Four methods for measuring quantities of 12 plant-available nutrients were compared using three sandy soils in a series of three experiments. Three of the methods use different ion-exchange resin forms—bags, capsules, and membranes—and the fourth was conventional chemical extraction. The first experiment compared nutrient extraction data from a medium of sand saturated with a nutrient solution. The second and third experiments used Nakai and Sheppard series soils from Canyonlands National Park, which are relatively high in soil carbonates. The second experiment compared nutrient extraction data provided by the four methods from soils equilibrated at two temperatures, “warm” and “cold.” The third experiment extracted nutrients from the same soils in a field equilibration. Our results show that the four extraction techniques are not comparable. This conclusion is due to differences among the methods in the net quantities of nutrients extracted from equivalent soil volumes, in the proportional representation of nutrients within similar soils and treatments, in the measurement of nutrients that were added in known quantities, and even in the order of nutrients ranked by net abundance. We attribute the disparities in nutrient measurement among the different resin forms to interacting effects of the inherent differences in resin exchange capacity, differences among nutrients in their resin affinities, and possibly the relatively short equilibration time for laboratory trials. One constraint for measuring carbonate-related nutrients in high-carbonate soils is the conventional ammonium acetate extraction method, which we suspect of dissolving fine CaCO3 particles that are more abundant in Nakai series soils, resulting in erroneously high Ca2+ estimates. For study of plant-available nutrients, it is important to identify the nutrients of foremost interest and understand differences in their resin sorption dynamics to determine the most appropriate extraction method.

Preparation of high capacity chloroethylated strong base anion exchange resin using NO x

Suspension polymerization of styrene and divinylbenzene has been carried out in the presence of gelatin as stabilizer to form macroporous polystyrene divinylbenzene resin (PS–DVB). In order to prepare surface chloroethylated macroporous PS–DVB resin, it is nitrated (resin 2) using a mixture of NO and NO2 gases (called NO x ), is reduced to amine groups (resin 3), further reacted with dichloroethane, then quarternized (resin 6) using trimethyl amine. Simple material balance demonstrates that all NO x reacted show up as exchanging sites of resin 6 and this resin has at least three exchanging sites on every repeat unit. We have examined the effect of duration of nitration on the exchange capacity of resin 6 and it was found that it first increased with increase in the duration of nitration, reaching a broad maxima of 4.8 meq/g of wet resin with 69% moisture (or capacity of 15.5 meq/g of dry resin) for about 5 hr of nitration and when nitration is continued for a longer time there is a fall due to polymer degradation. This is to be compared with the commercial chloride form of strong base anion exchange resin, which has the exchange capacity of 1.68 meq/g of wet resin with 43.53% moisture (or capacity of 2.97 meq/g of dry resin). In order to assess the solvation ability of the chloroethylated resin, we evolved a three-stage drying procedure and showed that it holds moisture differently. On a dry gram basis, the chloroethylated resin is about five times superior compared to available commercial resin.

Structural Material Anomaly Detection System Using Water Chemistry Data, (IV)

A conception of the advanced water chemistry diagnosis system for detection of anomalies and preventive maintenance of system components is proposed. Extension of anomaly diagnosis knowledge and more reliable water chemistry data are indispensable to the advanced system. Then, correlations between water chemistry (conductivity and pH) change in reactor water and anomaly occurrence in the components of the feed water line are analyzed theoretically. These correlations are verified as applicable to extension of the diagnosis knowledge for anomalies in the components of the feed water line, such as resin intrusion, sea water Leakage at the condenser, and a breakdown in ion exchange capacity of resin at the condensate demineralizer.

Removal of Iron Cyanide from Gold Mill Effluents by Ion Exchange

Using a strongly basic anion exchanger (Rohm & Haas Amberlite IRA-958) laboratory ion exchange tests were conducted on the removal of iron cyanide from synthetic and actual gold mill effluents. Variables examined included the effects of pH, concentration and hydraulic loading of the feed on the resin exchange capacity and resin column utilization. The results showed ion exchange to be an effective method of removing iron cyanide to concentrations of less than 3 mg/L. Tests with synthetic gold mill effluents gave resin exchange capacities ranging from 13 to 34 mg CNFe/mL resin depending on the concentration of iron, copper and zinc cyanides in these solutions. When raw barren bleed was tested, an exchange capacity for the ferro/ferricyanides was determined to be ~6 to 8 mg CNFe/mL resin. For chlorinated barren bleed, a resin exchange capacity of 14 mg CNFe/mL resin was observed. A capacity of 19 mg CNFe/mL resin was achieved for tailings pond decant. Regeneration with 15% NaCl provided mixed results with recoveries ranging from 40 to 100% of the iron cyanide exchanged by the resin. Upon multiple exchange-regeneration cycles, the resin lost 25% of the exchange capacity for total cyanide during the first cycle. Subsequently, the loss in exchange capacity was approximately 1% per cycle. Pilot scale tests were considered essential prior to full scale system design.

Phosphates and ammonia recovery from secondary effluents by selective ion exchange with production of a slow-release fertilizer

A process for the reduction of eutrophic potential in urban secondary effluents. which comprises the selective exchange of phosphates on a weak anion resin and of ammonia on clinoptilolite, is described. Sodium chloride is used to regenerate both resins, with some Ca(OH) 2 added for clinoptilolite. By adding Mg(OH) 2, eventually precipitated with lime from sea water, the premium quality, slow-release fertilizer MgNH 4PO 4-6H 2O is recovered from the concentrated regeneration streams, which can then be recycled. Laboratory evaluations of the hydrolysis extent of the weak anion resin in the presence of bicarbonates showed that a steady-state is attained with resin exchange capacity reproducibly averaging about 80 mmol phosphates 1, −. The preliminary runs on a pilot plant for the tertiary treatment of urban sewage are also presented.

Adsorption of N′-(2-Hydroxyethyl)-ethylenediamine-N,N,N′-triacetic Acid on the Hydrogen Form of Resin

Abstract The adsorption of HEDTA (H3Ch) on the hydrogen form of Dowex 50W, X-8, 100–200 mesh, has been studied as a function of the concentration of H3Ch in the aqueous phase. The experiments were performed by means of either the column or a combination of the column and batch methods, with the latter being employed for the adsorption of HEDTA on the resin in equilibrium with dilute solutions. In solutions up to approximately 0.07 mol/l, such as H3Ch, the experimental data are consistent with the Langmuir equation expressed by: [H3Ch]/(‾ChT⁄E)=1⁄Bk+[H3Ch]⁄B. The adsorbed amount is represented in the term ‾ChT⁄E, where ‾ChT is the total amount of cationic species of HEDTA on the resin, and E, the exchange capacity of resin. A good straight line is obtained with B=0.571 and K=0.420. The results show that, because of a high concentration of hydrogen ion inside the resin, the adsorbed HEDTA is present mainly in the H5Ch2+ species and partly in the H4Ch+ species.

Isolation and analysis of adenovirus 12 sub-units from adenovirus type 12-infected cells.

THE isolation of adenovirus 12 group-specific (“A”) and type-specific (“C”) antigens has been described by Huebner et al.1 The method used for isolation of the sub-units was step by step elution from columns of diethylaminoethyl cellulose (DEAE). Because the amount of material available at a given time varied, reabsorption was less important in this procedure than with gradient elution procedures. Eluent changes were regulated by a series of tests using cell protein alone in order to eliminate the possibility of widening or tailing of bands. Virus-antigen mixtures were equilibrated with 0.01 M phosphate buffer at 6.8 pH. before application to the column of DEAE, which was prepared in 0.01 M phosphate buffer at pH of 7.2. All operations were carried out in a cold room. Sodium chloride solutions were prepared in 0.01 M phosphate buffer at 6.8 pH. so that there was a constant pH but an increase in salt concentration during elution. An investigation of the effectiveness of changes in salt concentration versus changes in pH with cell protein showed that a constant pH was desirable and that changes in salt fronts were predictable. It was necessary to re-cycle eluates once or twice over fresh columns in order to obtain purified material in single peaks. A critical aspect of the procedure was the resin exchange capacity of 0.56 m. equiv./g.