Transformation of Crystal Phase of Micron-sized Rutile TiO 2 and Investigation on its Sonocatalytic Activity
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Transformation of Crystal Phase of Micron-sized Rutile TiO2 and Investigation on its Sonocatalytic Activity Jun Wang Æ Wei Sun Æ Zhao Hong Zhang Æ Rong He Li Æ Rui Xu Æ Zhe Jiang Æ Zhi Qiang Xing Æ Xiang Dong Zhang
Received: 23 May 2007 / Accepted: 11 July 2007 / Published online: 28 July 2007 Springer Science+Business Media, LLC 2007
Abstract The partial transformation of crystal phase of micron-sized TiO2 powder from rutile to anatase was realized utilizing microwave irradiation in hydrogen peroxide solution. Afterwards, the ultrasound of low power was used as an irradiation source to induce the transition crystal TiO2 powder to perform the sonocatalytic activity through the degradation of azo fuchsine in aqueous solution. The results show that the sonocatalytic activity of the transition crystal TiO2 powder is obviously higher than that of pure micron-sized rutile and anatase TiO2 powders. The degradation ratio of azo fuchsine in the presence of the transition crystal TiO2 powder attains nearly 80% within 80 min ultrasonic irradiation. Keywords Transition crystal TiO2 powder Microwave Sonocatalytic activity Azo fuchsine
1 Introduction In recent years, a great deal of effort has been devoted to develop heterogeneous catalysts with high catalytic activities for solving environmental problems [1–3]. The TiO2 powder has been believed to be the most promising semiconductor material for long time, due to its superior photoreactivity, nontoxicity and long-term stability. It is well J. Wang (&) W. Sun R. H. Li R. Xu Z. Jiang Z. Q. Xing X. D. Zhang Department of Chemistry, Liaoning University, Shenyang 110036, P.R. China e-mail: [email protected] Z. H. Zhang Department of Environment Science, Liaoning University, Shenyang 110036, P.R. China
known that the photocatalytic activity of the TiO2 powder depends on various parameters, including crystallinity, purity, surface area and density. Furthermore, the most significant factor is the crystal phase of TiO2 powder [4, 5]. In general, the photocatalytic activity of anatase phase TiO2 powder is better than that of rutile phase TiO2 powder [6]. In addition, a recent study showed that a mixture of both micron-sized anatase and rutile TiO2 powder exhibited higher photocatalytic activity as well as effective degradation ability compared with pure anatase or rutile TiO2 powder [7]. However, the photocatalytic degradation must need ultraviolet light to induce TiO2 powder, which costs lots of electric energy. Moreover, in any case, this method is not suitable for the treatment of non- or lowtransparent organic wastewaters. In fact, it can avoid these disadvantages to utilize ultrasonic irradiation. The penetrating ability of ultrasound is very strong for any water medium and its penetrating depth can ordinarily attain to 20–30 cm [8]. Besides, the ultrasound can usually be competent for catalyzing those chemical reactions as the ultraviolet and visible lights catalyzing [9, 10]. Hence, the ultrasound has been used as irradiation source instead of ultraviolet a
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