Dowex 1 resin adsorption

Home, R. A., R. H. Holm, and M. D. Meyers. 1957. The adsorption of zinc(II) on anion-exchange resins. II. Stoichiometry, thermodynamics, loading studies, Dowex-2 adsorption and factors influencing the rate of the adsorption process. J. Phys. Chem. 61 1655-1661. 

Purification of Antibiotic 66-40 — Dissolve 28 g of crude Antibiotic 66-40 in 100 ml of distilled water and charge to an anion exchange adsorption column (Dowex 1 X2) in the hydroxyl form. Slurry 2,000 g of the resin in water in to a column 2yj in diameter and 36 "high. Elute the column with distilled water at a rate of about 23 ml/min collecting 100 ml fractions and monitor with a conductivity meter and by disc testing against Staphylococcus aureus. 

Sakurada et al.88, 145, 146 hydrolyzed aliphatic esters having various hydrophobicities with cation-exchange resins, Dowex 50 w, and found a close correlation between the accelerating factor and the degree of ester adsorption toward the resins. 

Application of equation 10 to the experimental D vs. [HSOIJ] data determined at 25°C and both 1 and 2 M acidity yielded straight line plots with slopes indistinguishable from zero and reproduced the Bi values determined in a non-linear regression fit of the data. This result implies no adsorption of PuSO by the resin and justifies use of the simpler data treatment represented by equation 2. A similar analysis of the Th(IV)-HSOiJ system done by Zielen (9) likewise produced results consistent with no adsorption of ThS0 + by Dowex AG50X12 resin. 

The analytical methods for a-sulfo fatty acid esters reported in the literature deal with the determination of the surfactants in different matrices like detergents or product mixtures from the fabrication. The methyl esters of a-sulfo fatty acids can be separated from a mixture of different surfactants together with sulfonated surfactants by adsorption on an anionic exchanger resin such as Dowex 1X2 or 1X8. Desorption from the exchanger resin is successful with sodium hydroxide (2%) in a 1 1 mixture of isopropanol and water [105]. 

Remove unreacted N-acetyl homocysteine thiolactone and reaction by-products by gel filtration or dialysis against lOmM sodium phosphate, 0.15M NaCl, lOmM EDTA, pH 7.2. Other buffers suitable for individual protein stability may be used as desired. For the silver nitrate-containing reaction, removal of the silver-thiourea complex may be done by adsorption onto Dowex 50, and the protein subsequently eluted from the resin by 1M thiourea. Removal of the thiourea then may be done by gel filtration or dialysis. 

Hackenthal48 studied the contents of KDO and NeuAc in 19 strains of Neisseria meningitidis. Following acid hydrolysis of acetone-dried cells, both KDO and NeuAc were separated from the mixtures by adsorption on Dowex-1 X-8 ion-exchange resin, and were eluted together by 0.6 M formic acid. The sum of periodate-TBA reactivity was determined by Warren s procedure.13 The content of NeuAc was de-... 

The residue was diluted in water (5 mL) and, if necessary, the pH adjusted to 7.0 with 1 M KOH before adsorption of the product on a column of Dowex 1X8 resin (200-400 mesh, AcO form, 2 cm x 10 cm). The column was washed with water (50 mL) and then eluted with AcOH aqueous solutions (50 mL of 0.1 m, 50 mL of 0.2 m and 50 mL of 0.5 M AcOH). The ninhydrin-positive fractions were combined and dried under reduced pressure to afford (25,4/ )-4-methyl glutamic acid 2 isolated as a white solid (192 mg, 41 %) and with a high purity (>98 %). 

The parfait-distillation method uses a sequential series of adsorbents to remove contaminants from water and vacuum distillation to recover unadsorbed materials. This method recovers a wide range of neutral, cationic, anionic, and hydrophobic contaminants. The first adsorbent, porous polytetrafluoroethylene (PTFE), removed humic acid and a broad range of hydrophobic compounds. PTFE was followed by Dowex MSC-1 and then Duolite A-162 ion-exchange resins. A synthetic hard water spiked parts-per-billion concentrations with 20 model compounds was used to evaluate the method. Poorly volatile, neutral, water-soluble species (glucose) cationic aromatics and most hydro-phobic compounds were recovered quantitatively. Model ampho-terics were removed from the influent but were not recovered from the adsorption beds. The recovery of model acids and bases ranged from 22% to 70% of the amount applied. 

Commercial yeast invertase (Bioinvert ) was immobilized by adsorption on anion-exchange resins, collectively named Dowex (1x8 50-400,1x4 50-400, and 1x2 100-400). Optimal binding was obtained at pH 5.5 and 32°C. Among different polystyrene beads, the complex Dowex-1x4-200/invertase showed a yield coupling and an immobilization coefficient equal to 100%. The thermodynamic and kinetic parameters for sucrose hydrolysis for both soluble and insoluble enzyme were evaluated. The complex Dowex/inver-tase was stable without any desorption of enzyme from the support during the reaction, and it had thermodynamic parameters equal to the soluble form. The stability against pH presented by the soluble invertase was between 4.0 and 5.0, whereas for insoluble enzyme it was between 5.0 and 6.0. In both cases, the optimal pH values were found in the range of the stability interval. The Km and Vmax for the immobilized invertase were 38.2 mM and 0.0489 U/mL, and for the soluble enzyme were 40.3 mM and 0.0320 U/mL. 

The data in Figure 12.24 show the potentiometric titrations of a metal-exchange synthetic resin (Dowex 50W-X8) known to produce relatively weak metal-surface complexes (outer-sphere complexes). These data show that when the resin was saturated with Ca2+, no titration plateau (region of Na+, NH4 or NH3 adsorption) was exhibited. When the resin was saturated with Cu2+, up to two titration plateaus were exhibited, depending on the type of titrant used. When NaOH was the titrant, one apparent titration plateau was exhibited, whereas when NH4OH was the titrant, two... 

Figure 12 JO. Freundlich plots of Cd adsorption by Dowex 50W-X8 cation-exchange resin with a background electrolyte of 20 mmol L l KC1 or NH4C1 plus 5 mmolc L l CaCl2. The exchanger was first repeatedly washed with background electrolyte (from Evangelou, 1997, unpublished data).

To cause adsorption of the glucose-1-phosphate by the IR-45, gently pour the acidic solution treated with Dowex 50 (steps 13 and 14 of the protocol for Day 2) onto the column, avoiding the introduction of air bubbles into the resin bed. Open the screw clamp and adjust the flow rate to about 15 ml/min. Pass the entire solution through the IR-45 resin without permitting air to enter the column. 

The neodymium ion concentration in the organic phase was measured by back-extraction with 6M nitric acid, removal of the neodymium by adsorption with the cation exchange resin, Dowex 50 x 8, and titration of the neodymium-free aqueous phase with NaOH using phenolphtalein... 

Using a Dowex A-1 resin, which has a polystyrene matrix with iminodiacetic chelating groups, peroxy compounds of Cr and V were separable by adsorption, while Nb, Ta and W were not adsorbed ... 

The purpose of this study was to investigate the anionic exchange behavior of neptunium(V) in sulfate-sulfuric acid, because neptunium is often present as a contaminant during the separation of other actinides (l ). Sulfuric acid systems are seldom utilized in industrial processes, but are often used as part of a laboratory analytical procedure. Literature on neptunium in HC101, HC1, HC1-HF, and HNO3 is quite complete, but the information on the H2S0l system is sketchy at best. There is one report 2) that neptunium(V) is adsorbed strongly on Dowex 2 resin from 0.1 IT to 1 IT H SOip Our measurements indicate that there is very little adsorption of Np(V) on Dowex 1 resin even at low concentrations of sulfate-sulfuric acid. We believe the differences in chemical structure of the two resins are not sufficient to explain the disparity in adsorption. 

The most significant difference between Dowex 1 and Dowex 2 resin is in the order of selectivity of the hydroxide ion. All other mechanical variables between the two resins, such as pore size, shrinkage, capacity and water content, are negligible dif-erences. We conclude that these differences are insufficient to explain the disparity of adsorption of neptunium. 

We have measured the adsorption of Np(V) on Dowex 1 anion exchange resin from solutions of sulfuric acid that had increasing amounts of sulfate salts added. We found that Np(V) did not adsorb significantly at any acid or sulfate concentrations. The measured Kp s are largest at low concentrations of sulfate and sulfuric acid. The Kp s decreased as both the sulfate or sulfuric acid concentrations increased. 

Carta and Dinerman [22] have observed the adsorption azeotrope experimentally for the separation of a-aminobutyric acid and isoleucine on Dowex 50W-X8 resin, a sulfonated styrene-divinylbenzene copolymer which is moderately cross-linked. Figure 12.13a shows the experimental and calculated band profiles for the case of a separation azeotrope with a 125 mM NaOH solution as the displacer. Further increase in the column length results in the same normalized profile, which means that steady state has been reached with incomplete separation. Figure 12.13b illustrates the separation with a 25 mM NaOH solution as the displacer. Complete separation occurs. 

Figure 5 shows plutonium adsorption Kd values for three anion exchange resins over a pH range of 4 to 8. Plutonium adsorption on each of the three resins, Lewatit MP-500-FK, Dowex 2IK, and Dowex M-41, increased significantly as the pH increased. This was expected since anionic hydoxyl and carbonate complexes are more stable at higher pH. Since these resins are not effective plutonium adsorbents below a pH of 7 or 8, they are not useful in wastewater treatment (at least when used alone). 

Experiments were performed for the removal of Cr, Fe", and with Dowex XFS 4195.02 ion exchange resin at 25 C. A mathematical model for the removal of both Cr and from aqueous solutions in the presence of the resin was developed with the assumption that intraparticle diffusion is a controlling step for the adsorption of the heavy metal ions on the resin. The intraparticle diffusivities of Cr and Cu throuqh the resin were obtained to be 0.5 and 0.03 - 0.05 cnr/min, respectively. A series of experiments on the... 

Figure 1. Isotherm equilibrium adsorption of Cu on Dowex XFS 4195.02 ion exchange resin at 25 C.

In this way Consden et al. (1948) and Drake (1947) separated glutamic and aspartic acid on columns of Amberlite IR.-4 (polyamine anion exchanger) maintained at pH 2.5, and this type of column has been used to separate acidic peptides from a wool hydrolyzate (Consden et al., 1949). More recently Stein and Moore (1949) have obtained excellent fractionations of amino acids on columns of Dowex-50 (cation exchanger, sulfonic acid groups) developed with 1.5-4 N HCl. The separations obtained are almost certainly due to differences in adsorption affinity for the resin, as well as to charge effects. At the pH used the only partially... 

Some polystyrene resins (cross-linked with DVB) are specially modified to have chelating functional groups bound to the matrix so as to make them selective towards certain ions. Such resins with iminodiacetic acid groups are marketed under the trade names Dowex A-1 (Dow Chemical) and Chelex 100 (Bio-Rad Laboratories). The complex (XXVI) formation constants with metal ions of the chelating resin are so large that the resin absorbs metal ions equivalent to the iminodiacetic acid groups (used in sodium salt form), i.e., the efficiency of metal ion adsorption is near 100%. A particular metal ion can be removed by controlling the pH of aqueous solution. For example, at pH 2, mercury and copper ions are... 

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