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Transactions: WSEAS TRANSACTIONS ON ENVIRONMENT AND DEVELOPMENT
Transactions ID Number: 89-521
Full Name: Leticia M. Torres-Martínez
Position: Professor
Age: ON
Sex: Female
Address: Ciudad Universitaria s/n
Country: MEXICO
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E-mail address: lettorresg@yahoo.com
Other E-mails: letorre@fic.uanl.mx
Title of the Paper: Bi2MTaO7 (M = Al, Fe, Ga, In) photocatalyst for organic compounds degradation under uv and visible light
Authors as they appear in the Paper: Leticia M. Torres-Martinez, Isaias Juarez-Ramirez, Juan S. Ramos-Garza, Francisco Vazquez-Acosta, Soo Wohn Lee
Email addresses of all the authors: lettorresg@yahoo.com,isajua13@yahoo.com,seram8@hotmail.com,franvaz@yahoo.com.mx,swlee@sunmoon.ac.kr
Number of paper pages: 10
Abstract: Pyrochlore-type structure compounds, Bi2MTaO7 (M = Al, Fe, Ga, In), were synthesized by both the sol-gel and solid state method. In order to evaluate their photocatalytic activity, these compounds were tested on the degradation reaction of alizarin red S, methyl orange and phenol in aqueous solution. The characterization of the compounds included: XRD, SEM/EDS, SBET area, Eg value, DTA/TGA and FTIR. Pyrochlore-type structure compounds were obtained at lower temperatures (600-800°C) when they were prepared by the sol-gel method. The morphology of these compounds revealed the presence of nanoparticles. These materials also presented better SBET values (from 58 to 11 m2.g-1) than those obtained by the solid state method (<5 m2.g-1). All the materials showed Eg values within the visible light region (2.2-1.3 eV). Iron-containing pyrochlore prepared by the sol-gel method had the best performance as photocatalyst under visible light conditions for alizarin red S degradat!
ion, and under UV-light for phenol degradation. The photocatalytic results suggested this tendency: Fe > In > Al > Ga for alizarin red s, and Fe > Ga > Al > In, for phenol degradation. In addition, the photocatalytic tests on alizarin red s and methyl orange under UV light showed the following tendency: In > Fe > Al > Ga. Best half time life (t1/2) was obtained for alizarin red S degradation, ~30 min., using Bi2InTaO7 as photocatalyst, which was prepared by both the sol-gel method (at 600°C) and the solid state method (at 950°C). It seems that crystal structure has more influence than specific surface area for the organic compounds degradation carried out in this work.
Keywords: Pyrochlore-type structure; Sol-gel; Photocatalytic performance; Degradation reaction; Alizarin red S
EXTENSION of the file: .doc
Special (Invited) Session: Photocatalytic performance of pyrochlore-type structure compounds, Bi2MTaO7 (M = Al, Ga, Fe or In), on alizaryn red s degradation
Organizer of the Session: 640-254
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