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Title: Heterogeneous photodegradation of bisphenol A with iron oxides and oxalate in aqueous solution
Authors: Li, Fang-bai
Li, Xiang-zhong
Li, Xiao-min
Liu, Tong-xu
Dong, J.
Subjects: Bisphenol A
Iron oxides
Oxalic acid
Issue Date: 15-Jul-2007
Publisher: Elsevier
Source: Journal of colloid and interface science, 15 July 2007, v. 311, no. 2, p. 481-490.
Abstract: To understand the degradation of endocrine disrupting chemicals (EDCs) with existence of iron oxides and polycarboxylic acids in the natural environment, the photodegradation of bisphenol A (BPA) at the interface of iron oxides under UV illumination was conducted. Four iron oxides were prepared by a hydrothermal process and then sintered at different temperatures of 65, 280, 310, and 420°C named "IO-65," "IO-280," "IO-310," and "IO-420," respectively. The prepared iron oxides were characterized by X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) methods. The XRD pattern of IO-65 showed a crystal structure of lepidocrocite (γ -FeOOH) and that of IO-420 demonstrated a crystal structure of hematite (α-Fe₂O₃), while IO-280 and IO-310 have the mixed crystal structures of maghemite (γ -Fe₂O₃) and hematite. The BET results revealed that the specific surface areas decreased with the increase of sintering temperature. The results demonstrated that the photodegradation of BPA depends strongly on the properties of iron oxides and oxalate, and pH. The properties of iron oxides influenced strongly the dependence of the BPA degradation on the oxalate concentration. The optimal initial concentrations of oxalate for BPA degradation under UV illumination were determined to be 2.0, 2.0, 2.4, and 2.0 mMfor IO-65, IO-280, IO-310, and IO-420, respectively. The first-order kinetic constants k for BPA degradation under UV illumination in the presence of oxalate with the optimal initial concentration are ranked as IO-280 > IO-310 > IO-65 > IO-420. The experiments demonstrated that the optimal pH value should be in the range of 3–4. Furthermore, the dependence of BPA degradation should be also attributable to the formation of the dissolved Fe–oxalate in the solution and the adsorbed Fe–oxalate on the surface of iron oxides, and also the formation of hydrogen peroxide.
Rights: Journal of Colloid and Interface Science © 2007 Elsevier. The journal web site is located at
Type: Journal/Magazine Article
DOI: 10.1016/j.jcis.2007.03.067
ISSN: 0021-9797
Appears in Collections:CEE Journal/Magazine Articles

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