Visible‐light photocatalytic degradation of methyl orange over spherical activated carbon‐supported and Er3+:YAlO3‐doped TiO2 in a fluidized bed. Issue 5 (30th April 2014)

• Record Type: Journal Article
• Authors: Dong, Shanshan; Zhang, Xueying; He, Furong; Dong, Shuangshi; Zhou, Dandan; Wang, Bo
• Is Part Of: Journal of chemical technology & biotechnology. Volume 90:Issue 5(2015:May)
• Page Start: 880
• Page End: 887
• Publication Date: 2014-04-30
• Subjects: Biotechnology -- Periodicals; Chemistry, Technical -- Periodicals; Chemical engineering -- Periodicals; Industries -- Environmental aspects -- Periodicals; 660
• DOI: 10.1002/jctb.4391
• Languages: English
• ISSNs: 0268-2575

Abstract

<abstract abstract-type="main" id="jctb4391-abs-0001"> <title>Abstract</title> <sec id="jctb4391-sec-0001" sec-type="section"> <title>BACKGROUND</title> <p id="jctb4391-para-0001">Powdered photocatalyst by doping TiO<sub>2</sub> with upconversion luminescence agents achieved visible light induced photocatalysis. However, slurry photocatalysts are difficult to recover from the treated liquor. In the present study, spherical activated carbon (SAC)‐supported and Er<sup>3+</sup>:YAlO<sub>3</sub>‐doped visible‐light responsive photocatalyst (Er<sup>3+</sup>:YAlO<sub>3</sub>/TiO<sub>2</sub>‐SAC) was synthesized and characterized. The photocatalytic performance of photocatalyst was examined for degradation of methyl orange (MO) in a liquid–solid fluidized bed photoreactor under visible‐light irradiation.</p> </sec> <sec id="jctb4391-sec-0002" sec-type="section"> <title>RESULTS</title> <p id="jctb4391-para-0002">Two notable UV emission peaks at 320 and 360 nm were observed for Er<sup>3+</sup>:YAlO<sub>3</sub> by visible light excitation, which were assigned to the transition of <sup>2</sup>P<sub>3</sub><sub>/2</sub>→<sup>4</sup>I<sub>15</sub><sub>/2</sub> and <sup>4</sup>D<sub>5</sub><sub>/2</sub>→<sup>4</sup>I<sub>11</sub><sub>/2</sub>, respectively. An optimum 8 h photodecolorization efficiency of 65.3% was obtained from the fluidized bed with reaction rate constant 22.17 mg L<sup>−1</sup> h<sup>−1</sup>. The degradation rate first increased and then decreased with the increasing expansion ratio, and the optimum expansion ratio was found to be 130%.</p> </sec> <sec id="jctb4391-sec-0003" sec-type="section"> <title>CONCLUSION</title> <p id="jctb4391-para-0003">Optical characterization revealed that Er<sup>3+</sup>:YAlO<sub>3</sub> could convert incident visible‐light to UV, which can then be utilized by TiO<sub>2</sub> for photocatalysis. The visible light generated by Er<sup>3+</sup>:YAlO<sub>3</sub> emissions were not used by TiO<sub>2</sub> because of its high band gap. The photocatalytic degradation of MO in the fluidized bed photoreactor followed the Langmuir–Hinshelwood kinetics model. © 2014 Society of Chemical Industry</p> </sec> </abstract>