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Title Synthesis and application of novel hydroxylated thia-crown ethers as composite ionophores for selective recovery of Ag+ from aqueous sources
Posted by Francis Kirby Burnea
Authors Hiluf T Fissaha, Grace M Nisola, Francis Kirby Burnea, Jin Yong Lee, Sangho Koo, Soong-Peong Lee, Kim Hern, Wook-Jin Chung
Publication date 2020/1/25
Journal Journal of Industrial and Engineering Chemistry
Volume 81
Pages 415-426
Publisher Elsevier
Abstract Selective recovery of silver ions Ag+ has been a big challenge due to its difficult separation from complex aqueous feed streams. Herein, four novel highly selective 13- to 19-membered thia-crown ethers (TCEs) were successfully developed by intermolecular cyclization of S- and O-containing intermediates. The TCEs have reactive hydroxyl group(s) for coating on solid supports. To evaluate their ability to capture Ag+, the TCEs were coated on polypropylene (PP) membrane (TCE@PP) at high loading (∼280 wt%) via wet-incipient technique with glutaraldehyde acetalization. Adsorption results of all TCE@PP reveal high Ag+ capacities with qe ∼124–179 mg g−1, excellent Ag+ selectivities with Kd ∼291–778 L g−1 and rapid uptake rate within 1 h. But DH19-TCE4 or 19TCE@PP is the most effective as it achieved 96% Ag+ complexation compared with others ∼53–86% at feed Co = 1.5 mM. Density functional theory calculations reveal that DH19-TCE4 had the closest cavity size (∅c = 2.35 Å) with Ag+ (∅Ag+ = 2.30 Å), the most negative binding energy (BE = −65.76 kcal mol−1), and the least cavity distortion during Ag+ complexation. All adsorbents are reusable and stable with consistent performance even after five cycles of adsorption/desorption runs. Overall results demonstrate the effectiveness of the synthesis strategies for TCEs and their high potential as adsorbents, especially DH19-TCE4, for selective Ag+ recovery from aqueous sources.
Index terms / Keywords AdsorbentsSeparationSelectivitySilverThia-crown ethers
DOI AdsorbentsSeparationSelectivitySilverThia-crown ethers