Highly efficient sorption and luminescence sensing of oxoanionic species by 8-connected alkyl-amino functionalized Zr4+ MOFs. Issue 45 (1st November 2022)

• Record Type: Journal Article
• Authors: Pournara, Anastasia D.; Evangelou, Dimitrios A.; Roukounaki, Christina; Andreou, Evangelos K.; Armatas, Gerasimos S.; Lazarides, Theodore; Manos, Manolis J.
• Is Part Of: Dalton transactions. Volume 51:Issue 45(2022)
• Page Start: 17301
• Page End: 17309
• Publication Date: 2022-11-01
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt02848d
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Alkylamino-functionalized Zr 4+ MOFs with 8-c nets and easily exchangeable terminal OH − /H2 O ligands show remarkable sorption efficiency for toxic and radionuclide-related oxoanions and sensing capability for hexavalent chromium in ppb levels. Abstract : In the present study we provide the sorption properties of four 8-connected Zr 4+ MOFs with the general formula H16 [Zr6 O16 (RNH-BDC)4 ]·solvent (RNH-BDC 2− = 2-alkyl-amine-terephthalate; R = ethyl-, ET-MOF ; R = propyl-, PROP-MOF ; R = isobutyl-, SBUT-MOF ; R = n -butyl, BUT-MOF ) towards toxic Cr(vi ) and radionuclide-related ReO4 − oxoanions. These MOFs represent superior sorbents for the removal of oxoanionic species, in terms of kinetics, sorption isotherms, selectivity and regeneration/reusability. The excellent sorption capability of the MOFs is due to a combination of surface and intra-framework sorption phenomena. The latter process proceeds via replacement of terminal water/hydroxyl ligands from the Zr6 clusters and subsequent binding of oxonanions to the Zr 4+ centers, a fact that was proved via Rietveld PXRD analysis for the anion-loaded BUT-MOF . Importantly, BUT-MOF demonstrated an exceptional sorption capacity for Cr2 O7 2− (505 mg g −1 ) and was further utilized in a sorption column in the form of MOF/calcium alginate beads, displaying remarkable removal efficiency towards industrial (chrome-plating) wastewater. Furthermore, the luminescence Cr(vi ) sensing properties of BUT-MOF were explored in detail, presenting high sensitivity (detection limits as low as 9 ppb) and selectivity for these species against various competitive anions.