scholarly journals Extraction of Ascorbic Acid from Acerolas (Malpighia punicifolia L.)

1969 ◽  
Vol 39 (4) ◽  
pp. 184-189
Author(s):  
R. Santini, Jr. ◽  
J. Nevarez
Keyword(s):  
Ascorbic Acid ◽  
Anion Exchange ◽  
Dilute Hydrochloric Acid ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Cation Exchange Resin ◽  
Ion Exchange Resins ◽  
Anion Exchange Column ◽  
Commercial Process ◽  
Exchange Resins

The acerola is considered to be the best natural source of ascorbic acid, it yields from two to four crops during the year, and the ascorbic acid is found dissolved in the juice. Therefore, a method which was used previously for separating and crystallizing the ascorbic acid present in the green walnut hulls, but which could not be applied commercially thereto, has been modified and applied to the acerola. The method involved the use of ion-exchange resins. A cation-exchange resin was used to lower the pH below 2 and an anion-exchange resin to absorb the ascorbic acid. This acid was eluted from an anion-exchange column with a dilute hydrochloric acid Solution. On a laboratory scale the yields obtained were relatively high and in a continuous commercial process the yield should be about 88 percent.

scholarly journals Isolation and radiochemical purification of samarium isotopes using ion exchange resins АВ 17×8 AND KU-2

2021 ◽  
Vol 21 (4) ◽  
pp. 368-377
Author(s):  
Sayan E. Salmenbayev ◽  
◽  
Nazgul K. Nurgaysinova ◽  
Gani M. Yessilkanov ◽  
Аray E. Temirzhanova ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Anion Exchange ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Chemical Elements ◽  
Cation Exchange Resin ◽  
Internal Exposure ◽  
Ion Exchange Resins ◽  
Exchange Resins

The relevance of the research is caused by the need to develop a methodological base for determining 151Sm content in the soil cover of radioactively contaminated territories of Kazakhstan. The developed method for the determining of 151Sm will make it possible to assess the levels of soil contamination with this radionuclide, to determine the character of its spatial distribution, to allow estimating the internal exposure doses for the personnel and the population. The aim of the research is to carry out the isolation and radiochemical purification of samarium isotopes from acid solutions via using ion-exchange resins AV 17×8 and KU-2. Objects: salt solutions based on nitric and hydrochloric acid containing the stable isotopes of some natural, artificial β-emitters and isotopes of U and Th. The concentrations of nitric and hydrochloric acids were equal to the concentrations of the same acids used in the routine analysis of Pu and Am. Concentrations of chemical elements were determined using the Agilent 7700x quadrupole mass spectrometer and the iCAP 6300 Duo atomic emission spectrometer. The results of the experiments on the isolation and radiochemical purification of samarium isotopes from acidic solutions using anion-exchange resin AV 17×8 and cation-exchange resin KU-2 have been presented. It has been shown that the Sm-fraction can be purified from alkaline elements, Tl and U isotopes using the KU-2 cation-exchange resin. In turn, the isotopes U, Fe and Co can be removed using an anion exchange resin in 9M HCl media.

scholarly journals Mg/Al double-metal hydroxide regeneration of anion exchange resin by electric field intensification

2016 ◽  
Vol 75 (6) ◽  
pp. 1309-1318 ◽  
Author(s):  
Ying Wang ◽  
Zhun Li ◽  
Yansheng Li ◽  
Zhigang Liu
Keyword(s):  
Electric Field ◽  
Anion Exchange ◽  
Exchange Resin ◽  
Ph Value ◽  
Anion Exchange Resin ◽  
Cost Effective ◽  
Regenerative Capacity ◽  
Metal Hydroxides ◽  
Anion Exchange Resins ◽  
Exchange Resins

Fouled anion exchange resins were regenerated by electric field intensification of Mg/Al double-metal hydroxides. Regenerative experiments were performed with varying voltages (10–30 V) and dosages of Mg/Al hydroxides (0.045–0.135 mol and 0.015–0.045 mol, respectively) for 1–5 h. Optimal results were obtained under the following regenerative conditions: 20 V, 4 h, and 0.09/0.03 mol of Mg/Al hydroxides. The maximum regenerative capacity of resins was increased to 41.07%. The regenerative mechanism was presented by Fourier-transform infrared spectrum of resins and Mg/Al hydroxides, and the regenerative degree was analyzed with respect to conductivity, pH value, and electric current. Mg/Al hydroxides were also recycled after the regeneration. This method was proven to be cost-effective and environmentally friendly.

scholarly journals Removal of Hexavalent Chromium Ions from Aqueous Solutions by an Anion-Exchange Resin

2008 ◽  
Vol 26 (9) ◽  
pp. 693-703 ◽  
Author(s):  
P. Senthil Kumar ◽  
K. Kirthika ◽  
K. Sathish Kumar
Keyword(s):  
Aqueous Solutions ◽  
Anion Exchange ◽  
Hexavalent Chromium ◽  
Exchange Resin ◽  
Ph Value ◽  
Anion Exchange Resin ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Isotherm Models ◽  
Exchange Resins

The removal of hexavalent chromium, Cr(VI), from aqueous solutions under different conditions using an anion-exchange resin (AXR) as an adsorbent was investigated under batch conditions. Such studies indicated that the percentage adsorption decreased with increasing initial Cr(VI) concentration, with the maximum removal of such ions occurred at a pH value of ca. 2.0. Both the Langmuir and Freundlich isotherm models were capable of reproducing the isotherms obtained experimentally. The sorption process was rapid during the first 20 min with equilibrium being attained within 30 min. The process followed first-order kinetics. The results demonstrate that such anion-exchange resins can be used for the efficient removal of Cr(VI) ions from water and wastewater.

Exchangeable Cations and Picloram Sorption by Soil and Model Adsorbents

Weed Science ◽  
1979 ◽  
Vol 27 (3) ◽  
pp. 257-262 ◽  
Author(s):  
J. S. Arnold ◽  
W. J. Farmer
Keyword(s):  
Cation Exchange ◽  
Anion Exchange ◽  
Equilibrium Solution ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Cation Exchange Resin ◽  
Adsorptive Capacity ◽  
Solution Ph ◽  
Exchange Complex ◽  
Polyvalent Cations

The adsorption of picloram (4-amino-3,5,6-trichloropicolinic acid) was determined on an Aiken silt loam, on three cation exchange resins and on a single anion exchange resin. Adsorption data were evaluated using parameters in the Freundlich equation and their dependance upon cationic composition of the exchange complex, the ionic composition of the equilibrium solution, and the equilibrium solution pH. For the Aiken soil saturated with metallic cations the order of decreasing picloram adsorptive capacity was Fe+3= Cu+2> Al+3> Zn+2> Ca+2> native soil. Increases in adsorption compared to the native Aiken soil could be explained on the basis of decreases in the equilibrium solution pH except for Fe+3, Zn+2, and especially the Cu+2treatments. The adsorptive capacity of the Aiken soil was altered by the addition of several salts simulating addition of fertilizer salts. The Cu+2and Zn+2salts were the only treatments showing increased adsorption which could not be explained readily by pH changes. KH2PO4and NH2CONH2(urea) reduced picloram adsorption. Dowex 50-1 × 4, a strongly acidic cation exchange resin, showed increased picloram adsorptive capacity in the order Cu+2> Al+3> Ca+2> Zn+2= H+. Cellex CM, a weakly acidic cellulose exchanger had increased adsorptive capacities in the order of Cu+2> Ca+2> Al+3> Na+> Fe+3> Zn+2. Picloram adsorption by an anion exchange resin at pH 6.1 was nearly 100%. These results suggest that complex formation of picloram with polyvalent cations on the exchange complex is likely especially for Cu+2and to a lesser extent Fe+3and Zn+2. In soils such complex reactions would most probably involve organic matter, polyvalent cations, and picloram. The formation of chelate ring species is proposed.

scholarly journals Procedure to reduce sulphite in wine with anion-exchange resin

2012 ◽  
Vol 60 (8) ◽  
pp. 79-86
Author(s):  
Miroslav Horák ◽  
Pavel Híc ◽  
Eva Tománková ◽  
Josef Balík
Keyword(s):  
Tartaric Acid ◽  
Anion Exchange ◽  
Malic Acid ◽  
Anion Exchanger ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Sodium Bicarbonate Solution ◽  
Basic Anion Exchange Resin ◽  
Basic Anion ◽  
Exchange Resins

The aim of this experiment was to eliminate SO2 ions present in wine using the anion-exchanger resins. To compare the effectiveness, 2 following strongly basic anion-exchange resin were used. When activated, the sodium bicarbonate solution (activation solution I) is used to prevent parallel reduction of sulphites, tartates and malates, so the anion-exchange resins were activated in two-step activation. In the second step, it was immersed into a mixture of malic acid and tartaric acid (1:1). After the application of anex into wine, the content of total SO2 was reduced to 97–201 mg.L−1 (depending on the amount of anex added into the wine sample). According to our expectations, the variants with anion-exchange resin activated only with bicarbonate solution, the tartrates and malates were significantly reduced. If the anion-exchange resin was activated with a two-steps activation, the tartaric acid and malic acid were reduced in the range of ± 0.13 g.L−1. This phenomenon was strongly reflected at the anion-exchanger Aqua Osmotic 02. The changes in antioxidant content were not affected by the type of anion-exchange resin, the method of activation, or an amount of used anion-exchanger. The color parameters of wine, expressed by the L * a * b *, were not significantly affected by the effects of anion-exchange resin use.

Polymeric Resins Adsorb and Release Oryzalin in Response to pH

Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 157-163
Author(s):  
Glenn B. Fain ◽  
Timothy L. Grey ◽  
Glenn R. Wehtje ◽  
Charles H. Gilliam ◽  
Jason A. Osborne
Keyword(s):  
Anion Exchange ◽  
Maximum Concentration ◽  
Exchange Resin ◽  
Slow Release ◽  
Anion Exchange Resin ◽  
Anion Exchange Resins ◽  
Maximum Sorption ◽  
Polymeric Resins ◽  
Exchange Resins ◽  
Polymeric Anion

Two polymeric anion-exchange resins and one sorbent resin were evaluated for their propensity to adsorb, and subsequently desorb, oryzalin. The intent was to determine whether these resins could adsorb and subsequently release oryzalin in a manner that would render these resins as an option for slow-release herbicide delivery. The dinitroaniline herbicide oryzalin is weakly acidic with a dissociation constant (pKa) of 8.6. An additional objective was to determine whether altering the pH between sorption and desorption would enhance the desired performance. Maximum oryzalin sorption by the two anion-exchange resins was between 127 and 132 mg g−1ai. The sorbent resin was adsorbed at a maximum concentration of 191 mg g−1ai. Maximum sorption occurred with the pH 10 solutions with all resins. Average oryzalin desorption by the anion-exchange resin was between 0.12 and 3.84 mg g−1per desorption event. Maximum desorption occurred at pH 6.0. Results reveal that the resins evaluated may have merit for slow-release herbicide delivery.

scholarly journals Adsorption of Anthocyanins by Cation and Anion Exchange Resins with Aromatic and Aliphatic Polymer Matrices

2020 ◽  
Vol 21 (21) ◽  
pp. 7874
Author(s):  
Natalia Pismenskaya ◽  
Veronika Sarapulova ◽  
Anastasia Klevtsova ◽  
Sergey Mikhaylin ◽  
Laurent Bazinet
Keyword(s):  
Ion Exchange ◽  
Anion Exchange ◽  
Electrostatic Interactions ◽  
Exchange Resin ◽  
External Solution ◽  
Ion Exchange Resins ◽  
Internal Solution ◽  
Ph Shift ◽  
Anion Exchange Resins ◽  
Exchange Resins

This study examines the mechanisms of adsorption of anthocyanins from model aqueous solutions at pH values of 3, 6, and 9 by ion-exchange resins making the main component of heterogeneous ion-exchange membranes. This is the first report demonstrating that the pH of the internal solution of a KU-2-8 aromatic cation-exchange resin is 2-3 units lower than the pH of the external bathing anthocyanin-containing solution, and the pH of the internal solution of some anion-exchange resins with an aromatic (AV-17-8, AV-17-2P) or aliphatic (EDE-10P) matrix is 2–4 units higher than the pH of the external solution. This pH shift is caused by the Donnan exclusion of hydroxyl ions (in the KU-2-8 resin) or protons (in the AV-17-8, AV-17-2P, and EDE-10P resins). The most significant pH shift is observed for the EDE-10P resin, which has the highest ion-exchange capacity causing the highest Donnan exclusion. Due to the pH shift, the electric charge of anthocyanin inside an ion-exchange resin differs from its charge in the external solution. At pH 6, the external solution contains uncharged anthocyanin molecules. However, in the AV-17-8 and AV-17-2P resins, the anthocyanins are present as singly charged anions, while in the EDE-10P resin, they are in the form of doubly charged anions. Due to the electrostatic interactions of these anions with the positively charged fixed groups of anion-exchange resins, the adsorption capacities of AV-17-8, AV-17-2P, and EDE-10P were higher than expected. It was established that the electrostatic interactions of anthocyanins with the charged fixed groups increase the adsorption capacity of the aromatic resin by a factor of 1.8–2.5 compared to the adsorption caused by the π–π (stacking) interactions. These results provide new insights into the fouling mechanism of ion-exchange materials by polyphenols; they can help develop strategies for membrane cleaning and for extracting anthocyanins from juices and wine using ion-exchange resins and membranes.

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