Issue 1, 2017

Retracted Article: Mechanistic insights into the decontamination of Th(iv) on graphene oxide-based composites by EXAFS and modeling techniques

Abstract

The sorption mechanism of Th(IV) on amidoxime/graphene oxide composites was investigated by extended X-ray absorption fine structure (EXAFS) spectra and surface complexation modeling. It was found that amidoxime/graphene oxide composites possessed a variety of oxygen- and nitrogen-containing functional groups such as hydroxyl, carboxyl, carbonyl, amine and imine groups. The sorption kinetics and sorption isotherms of Th(IV) on amidoxime/graphene oxide composites can be satisfactorily fitted by the pseudo-second-order kinetic model and the Langmuir model, respectively. The maximum sorption capacity of Th(IV) on amidoxime/graphene oxide composites calculated from the Langmuir model at pH 2.0 and 293 K was 123.46 mg g−1. According to EXAFS analysis, the presence of a Th–C shell (R = 2.97 Å, CN = 4.9) indicated that inner-sphere surface complexation dominated the sorption of Th(IV) on amidoxime/graphene oxide composites at pH 2.0, whereas the occurrence of a Th–Th shell revealed that a surface precipitate dominated the sorption of Th(IV) on amidoxime/graphene oxide composites at pH 5.0. The pH-dependent sorption behaviors of Th(IV) on amidoxime/graphene oxide composites can be satisfactorily simulated by double layer modeling based on two inner-sphere surface complexes and a surface precipitate. These observations revealed that the amidoxime/graphene oxide composites can be regarded as a promising adsorbent to remove tetravalent radionuclides from aqueous solutions in environmental cleanup.

Graphical abstract: Retracted Article: Mechanistic insights into the decontamination of Th(iv) on graphene oxide-based composites by EXAFS and modeling techniques

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
08 Oct 2016
Accepted
09 Nov 2016
First published
10 Nov 2016

Environ. Sci.: Nano, 2017,4, 222-232

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