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Photodegradation kinetics of 2,6-dimetylphenol by natural iron oxide and oxalate in aqueous solution

Paper ID Volume ID Publish Year Pages File Format Full-Text
28310 44069 2012 7 PDF Available
Title
Photodegradation kinetics of 2,6-dimetylphenol by natural iron oxide and oxalate in aqueous solution
Abstract

Heterogeneous photodegradation of 2,6-dimethylphenol (2,6-DMP) in the natural iron oxide (NIO) system with oxalic acid under UV irradiation was investigated. The NIO was characterized by X-ray diffraction (XRD), X-ray fluorescence and Brunauer–Emmett–Teller (BET) methods. The XRD pattern of NIO showed a mixed crystal structure. In order to show the effect of temperature on the structure of NIO, the last one was calcined at 800 °C and 1000 °C. The XRD patterns of calcined iron oxides at 800 °C (NIO/800) and 1000 °C (NIO/1000) depict the conversion from mixed crystalline hematite to completely pure crystalline hematite. The experiments showed that the most effective catalyst for degradation of 2,6-DMP is NIO in presence of oxalate. The dependence of 2,6-DMP degradation was attributable to the formation of the dissolved Fe–oxalate in the solution and the adsorbed Fe–oxalate on the surface of natural iron oxide. The photodegradation of 2,6-DMP depends also on the oxalate and pH. The optimal initial concentration of oxalic acid was found to be 5 × 10−3 M. The results demonstrated that the optimal pH value should be in the range of 3–4. The use of 2.0% of isopropanol as a scavenger confirmed the intervention of hydroxyl radicals in the photodegradation of 2,6-DMP. Furthermore, an important effect of oxygen was observed.

► The natural iron oxide and oxalate system was used under UV irradiation. ► The process was applied in order to improve the degradation of 2,6-dimethylphenol. ► The optimal initial concentration of oxalic acid was found to be 5 × 10−3 M. ► The optimal pH value should be in the range of 3–4. ► The addition of isopropanol as a scavenger confirmed the intervention of •OH.

Keywords
2,6-Dimethylphenol; Photodegradation; Natural iron oxide; Oxalic acid; Dissolved Fe–oxalate; Hydroxyl radicals
First Page Preview
Photodegradation kinetics of 2,6-dimetylphenol by natural iron oxide and oxalate in aqueous solution
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 237, 1 June 2012, Pages 31–37
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering