Molecular Recognition and Scavenging of Arsenate from Aqueous Solution Using Dimetallic Receptors

• Published in: Chemistry : a European journal Vol. 20; no. 51; pp. 17168 - 17177
• Main Authors: Moffat, Chris D., Weiss, Dominik J., Shivalingam, Arun, White, Andrew J. P., Salaün, Pascal, Vilar, Ramon
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 15-12-2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Adsorption; Affinity; Aqueous solutions; Arsenates; Arsenates - chemistry; Arsenates - isolation & purification; arsenic; Beads; Binding; Chemistry; Crystal structure; Crystallography, X-Ray; dimetallic receptors; heavy metals; Hydrogen-Ion Concentration; Legislation; Organometallic Compounds - chemistry; Sodium Acetate - chemistry; Solutions; Sponges; Titration calorimetry; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - isolation & purification; Water Purification; Zinc; Zinc - chemistry; adsorption; arsenic; dimetallic receptors; heavy metals
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201404723

A series of copper(II), nickel(II) and zinc(II) dimetallic complexes were prepared and their affinities towards arsenate investigated. Indicator displacement assays (IDAs) were carried out to establish the complexes with best affinities towards arsenate. A di‐zinc complex (3) was selected and its arsenate‐binding abilities investigated by isothermal titration calorimetry (ITC). The X‐ray crystal structure of this metallo‐receptor bound to arsenate is also reported, which allowed us to establish the binding mode between 3 and this oxyanion. Immobilising 3 onto HypoGel resin yielded a novel adsorbent (Zn–HypoGel) with high affinity for arsenate. Adsorption of arsenate from competitive solutions and natural groundwater was greater than that of the commercially used iron oxide Bayoxide E33. Zn–HypoGel could be efficiently and simply regenerated by washing with sodium acetate solution.
An arsenate “sponge”: The arsenate‐binding ability of a series of metallo‐receptors is reported. From these, a di‐zinc complex has been shown to have very good affinity for arsenate in aqueous media and has been successfully attached to polymer beads. The resulting functionalized solid material has been successfully employed to remove arsenate from contaminated water to levels well below those currently allowed by legislation.