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Title: TiO₂hydrosols with high activity for photocatalytic degradation of formaldehyde in a gaseous phase
Authors: Liu, Tong-xu
Li, Fang-bai
Li, Xiang-zhong
Subjects: Air purification
TiO₂ hydrosol
Photocatalytic activity
Issue Date: 21-Mar-2008
Publisher: Elsevier
Source: Journal of hazardous materials, 21 Mar. 2008, v. 152, no. 1, p. 347-355.
Abstract: Two types of TiO₂hydrosols (TOSO and HTO) were prepared from titanium sulfate (TiOSO₄)and metatitanic acid (H₂TiO₃) by a chemical precipitation–peptization method, respectively. The prepared hydrosols were characterized by means of X-ray diffraction, particle size distribution, scanning electron microscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller and Barret–Joyner–Halender methods. The results showed that the TiO₂hydrosols with an anatase crystal structure had smaller particle sizes, higher surface areas, larger pore volume, and higher transparence than Degussa P-25 suspension. The photocatalytic activity of the TiO₂hydrosols was evaluated for formaldehyde degradation under UVA illumination in a gaseous phase. The results demonstrated that the photocatalytic activity with the catalyst loading of 2mg cm⁻² was ranked as an order of HTO> TOSO > P-25. The photocatalytic activity was further studied using the HTO catalyst under different experimental conditions. The results showed that catalyst loading, relative humidity, and initial concentration could influence the efficiency of HCHO photocatalytic degradation. It was found that a catalyst loading of more than 2mg cm⁻² and a relative humidity of 55% were two essential conditions for achieving the best performance under these experimental conditions. The repeated experiments indicated that the HTO catalyst was reasonably stable and could be repeatedly used for the HCHO oxidation under UVA irradiation. This investigation would be helpful to promote the application of TiO₂ photocatalytic technique for indoor air purification.
Rights: Journal of Hazardous Materials © 2007 Elsevier. The journal web site is located at
Type: Journal/Magazine Article
DOI: 10.1016/j.jhazmat.2007.07.003
ISSN: 0304-3894
Appears in Collections:CEE Journal/Magazine Articles

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