Stabilization of copper nanoparticles with volume- and surface-distribution inside ion-exchange matrices

Кравченко, Т. А.; Sakardina, E. A.; Kalinichev, A. I.; Золотухина, Е. В.

doi:10.1134/s0036024415080178

Cited by 9 publications

(7 citation statements)

References 13 publications

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“…The adsorption of the molecular form of anthocyanins to these resins is mainly accomplished through π–π (stacking) interactions of the anthocyanin aromatic rings with each other and with the IER aromatic matrix [ 41 , 42 , 43 ]. The macroporous AV-17-2P resin has larger pores [ 84 ] than the AV-17-8 resin, allowing large anthocyanin molecules to penetrate more easily into the AV-17-2P resin and delivering its higher adsorption capacity and the adsorption factor of anthocyanins ( Table 1 ). At pH 3, the AV-17-8 anion-exchange resin adsorbs the least anthocyanins while the KU-2-8 cation-exchange resin ( Figure 10 a) adsorbs the most.…”

Section: Resultsmentioning

confidence: 99%

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

Pismenskaya

Сарапулова

Klevtsova

et al. 2020

IJMS

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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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Section: Resultsmentioning

confidence: 99%

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

Pismenskaya

Сарапулова

Klevtsova

et al. 2020

IJMS

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“…Fixed groups Polymer matrix True density, g cm −3 Specific volume, cm 3 g −3 Total exchange capacity, mmol cm −3 Anion-exchange resins AV-17-2P -N + (CH 3 ) 3 2% DVB + PS *1.06 5-7.5 [38] 0.80 ± 0.02 [39] AV-17-8chs (grade 1) -N + (CH 3 ) 3 8% DVB + PS 1.13 [40] 3.0 ± 0.3 [41] 1.12 ± 0.02 [39] Cation-exchange resin KU-2-8chs -S 8% DVB + PS 1.25 [40] 2.7 ± 0.2 [42] 1.80 ± 0.01 [39] 3…”

Section: Brandmentioning

confidence: 99%

Electrostatic Interactions of Ion-Exchange Materials with Anthocyanins in the Processes of Their Sorption and Electrodialysis Extraction from Liquid Media

Сарапулова

Klevtsova

Pismenskaya

2020

Membr. Membr. Technol.

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The nutritional value of wines as well as fruit and berry juices is to a large extent determined by the presence of anthocyanins in them, which possess antioxidant activity. To extract these substances from food waste as well as to condition juices and wines, ion-exchange resins and membranes based on them are being increasingly used. The kinetics of sorption of anthocyanins by ion-exchange resins from model solutions with pH of 3, 6, and 9 is studied. It is shown that the Donnan exclusion of coions leads to a change in the structure of anthocyanins in the internal solution of ion-exchange materials compared to the external solution. As a result, the electrostatic interactions of anthocyanins with ion-exchange materials are weakened or enhanced compared to the expected interactions based on pH of the external solution. Large anthocyanin molecules more easily penetrate heterogeneous ion-exchange membranes compared to the resins from which they are fabricated. The reason is the presence of extended macropores localized at the boundaries of the contacts of the reinforcing cloth and composite of the ion-exchange material with an inert binding agent in the membranes.

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“…The introduction of copper deposit in the matrix of anion exchangers is much more difficult than its deposition in the skeleton of cation exchange resins. Due to the presence of negatively charged functional groups of cation exchangers (sulfonic or carboxylic), the precursor of inorganic deposit-Cu 2+ ions-can be easily and quantitatively bind within the polymeric structure (Feng and Sun 2015;Kravchenko et al 2015). Since anion exchangers contain positively charged functional groups, penetration of the polymeric matrix by the Cu 2+ precursor is significantly impeded resulting in low efficiency of copper deposition which usually occurs on the outer surface of the polymeric beads.…”

Section: Introductionmentioning

confidence: 99%

Anomalous effect of Cu2O and CuO deposit on the porosity of a macroreticular anion exchanger

et al. 2021

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When synthesizing copper compounds containing polymeric adsorbents, it was found that the two copper oxides, Cu2O and CuO, deposited in the skeleton of a strongly basic macroreticular anion exchanger (An) radically diminished the porosity of the obtained composites in relation to the host material. In order to investigate this phenomenon more closely, An/Cu2O and An/CuO (both based on the commercial anion exchanger Amberlite IRA900Cl), containing 8.6 and 8.2 wt% Cu, respectively, were subjected to scrutiny. The porous characteristics of the thermally dried and freeze-dried samples were determined using the N2 adsorption–desorption method and mercury intrusion porosimetry. The thermally dried samples lost their porosity and increased their bulk density in relation to the pure resin indicated a significant reduction in their volume. It was found that during drying, the grains shrank as much as the pores collapsed. The decay of the porous structure resulted from the surface morphology of the Cu2O and CuO particles and their tendency to agglomerate. Both freeze-dried samples retained the porous characteristics typical for macroporous anion exchangers. In contrast to the most popular hybrid ion exchangers containing hydrated polyvalent metal oxides (such FeOOH), An/Cu2O and An/CuO showed markedly strong volume contraction effect in relation to moisture content. Graphical abstract

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Stabilization of copper nanoparticles with volume- and surface-distribution inside ion-exchange matrices

Cited by 9 publications

References 13 publications

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

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

Electrostatic Interactions of Ion-Exchange Materials with Anthocyanins in the Processes of Their Sorption and Electrodialysis Extraction from Liquid Media

Anomalous effect of Cu2O and CuO deposit on the porosity of a macroreticular anion exchanger

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