Adsorption and removal of oxo-anions of arsenic and selenium on the zirconium(IV) loaded polymer resin functionalized with diethylenetriamine-N,N,N',N'-polyacetic acid.
A polymer adsorbent in which a Zr(IV)-edta complex analogue is immobilized has been prepared and applied to the removal of oxo-anions of As(III), As(V) and Se(IV). Effective retention of these anions has been demonstrated with the proposed polymer complex system. The adsorption mechanism of oxo-anions onto the Zr(IV)-chelated polymer complex has been investigated using Zr(IV)-edta as the model compound. The formation of mixed complexes with oxo-anions has been exemplified by the isolation of the carbonato complex K2[Zr(CO3)edta].3H2O, the structure of which has been confirmed by X-ray crystallography. NMR study suggests that oxo-anions that form weak or moderate conjugate acids, including those of As(III), As(V) and Se(IV), can form mixed complexes with Zr(IV)-edta using the unsaturated coordination site. However, oxo-anions of strong conjugate acids did not show any appreciable interaction with this complex. According to these observations, retention of oxo-anions on the Zr(IV)-chelated polymer complex has been interpreted by a ligand substitution reaction. The adsorption characteristics of As(III), As(V) and Se(IV) on the Zr(IV)-loaded resin have been examined with respect to the equilibrium adsorption, percentage extraction and the effect of co-existing ions. The adsorption and desorption cycles of the oxo-anions have been demonstrated using a column packed with the proposed resin without any loss of column performance, which indicates the possibility for repeated use.
Suzuki
T M
TM
Tohoku National Industrial Research Institute, 4-2-1, Nigatake, Miyagino-ku, Sendai 983-8551, Japan. suzuki@tniri.go.jp
Tanaka
D A
DA
Tanco
M A
MA
Kanesato
M
M
Yokoyama
T
T
D019342:Acetic Acid / Q000737:chemistry; D000327:Adsorption; D001151:Arsenic / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D011073:Polyamines / Q000737:chemistry; D011108:Polymers; D012643:Selenium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014876:Water Pollution / Q000517:prevention & control; D015040:Zirconium / Q000737:chemistry*
D011073:Polyamines; D011108:Polymers; D014874:Water Pollutants, Chemical; C005391:diethylenetriamine; D015040:Zirconium; D012643:Selenium; D001151:Arsenic; D019342:Acetic Acid