title: Non-destructive separation of metal ions from wastewater containing excess aminopolycarboxylate chelant in solution with an ion-selective immobilized macrocyclic material.
abstract: Although the excellent metal-binding capacities of aminopolycarboxylate chelants (APCs) facilitate their extensive use, pre- and post-toxicity of APCs and their high persistence in aquatic environments evoke concerns. Several treatment techniques with a principal focus on the degradation of APCs at the pre-release step have been proposed. Here, we report a technique for the separation of metal ions from waste solution containing excess APCs using a solid phase extraction system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel. Synthetic metal solutions with 100-fold chelant content housed in H2O matrices were used as samples. The MRT gel showed a higher recovery rate compared with other SPE materials at 20 degrees C using a flow rate of 0.2 mL min(-1). The effects of solution pH, metal-chelant stability constants and ionic radii were assessed for 32 metals. Compared to the conventional treatment options for such waste solutions, our proposed technique has the advantage of non-destructive separation of both metal ions and chelants.
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan. hhiroshi@t.kanazawa-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hasegawa
authors.forename: Ismail M M
authors.initials: IM
authors.lastname: Rahman
authors.forename: Sanae
authors.initials: S
authors.lastname: Kinoshita
authors.forename: Teruya
authors.initials: T
authors.lastname: Maki
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Furusho
mesh_terms: D002412:Cations / Q000032:analysis / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008670:Metals / Q000032:analysis / Q000737:chemistry*; D009571:Nitrilotriacetic Acid / Q000737:chemistry; D004369:Pentetic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D002412:Cations; D002614:Chelating Agents; D047028:Macrocyclic Compounds; D008670:Metals; D014874:Water Pollutants, Chemical; C060068:diethylenetriaminetetraacetic acid; D004369:Pentetic Acid; D004492:Edetic Acid; D009571:Nitrilotriacetic Acid