Surface-active bismuth ferrite as superior peroxymonosulfate activator for aqueous sulfamethoxazole removal: Performance, mechanism and quantification of sulfate radical.

Author(s) Da Oh, W.; Dong, Z.L.; Ronn, G.; Lim, T.T.
Journal J Hazard Mater
Date Published 2017 Mar 05

A surface-active Bi2Fe4O9 nanoplates (BF-nP) was prepared using a facile hydrothermal protocol for sulfamethoxazole (SMX) removal via peroxymonosulfate (PMS). The catalytic activity of BF-nP was superior to other catalysts with the following order of performance: BF-nP>Bi2Fe4O9 (nanocubes)>Co3O4>Fe2O3 (low temperature co-precipitation method)>Fe2O3 (hydrothermal method)∼Bi2O3∼Bi(3+)∼Fe(3+). The empirical relationship of the apparent rate constant (kapp), BF-nP loading and PMS dosage can be described as follows: kapp=0.69[BF-nP](0.6)[PMS](0.4) (R(2)=0.98). The GC-MS study suggests that the SMX degradation proceed mainly through electron transfer reaction. The XPS study reveals that the interconversion of Fe(3+)/Fe(2+) and Bi(3+)/Bi(5+) couples are responsible for the enhanced PMS activation. The radical scavenging study indicates that SO4(-) is the dominant reactive radical (>92% of the total SMX degradation). A method to quantify SO4(-) in the heterogeneous Bi2Fe4O9/PMS systems based on the quantitation of benzoquinone, which is the degradation byproduct of p-hydroxybenzoic acid and SO4(-), is proposed. It was found that at least 7.8±0.1μM of SO4(-) was generated from PMS during the BF-nP/PMS process (0.1gL(-1), 0.40mM PMS, natural pH). The Bi2Fe4O9 nanoplates has a remarkable potential for use as a reusable, nontoxic, highly-efficient and stable PMS activator.

DOI 10.1016/j.jhazmat.2016.11.056
ISSN 1873-3336
Citation J Hazard Mater. 2017;325:7181.

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