Author:
Ardila-Arias Alba Nelly,Fuentes Zurita Gustavo,Martínez Miguel Ángel,Montes de Correa Consuelo
Abstract
The reactivity of pure hydrogen, isopropanol and formic acid as reducing agents was assessed for the liquid-phase perchloroethylene (PCE) hydrodechlorination (HDC) over 0.8% Pd/TiO2 sol-gel under mild reaction conditions. Additionally, the effect of the amount of water and sodium hydroxide added into the reaction mixture were studied. Fresh and used catalysts were characterized by AAS, H2-chemisorption, N2 adsorption-desorption, DRX, H2-TPR, TGA-DTG, UV-Vis DRS, NH3-TPD and TEM. Best results were obtained with hydrogen and isopropanol as reductants. The addition of NaOH signifi cantly increases the conversion of PCE with the above reducing agents. However, an excess of NaOH negatively affects the HDC reaction. Characterization of fresh and used catalysts reveals certain changes, such as: surface area and Pd dispersion decrease, increased superfi cial acidity and Pd particle size. However, some characteristics like Pd loading, TiO2 crystalline structure and Pd oxidation state remained.
Reference39 articles.
1. Universidad Pontífi cia Bolivariana. Área Metropolitana del Valle de Aburrá. “Actualización del inventario de emisiones atmosféricas en el Valle de Aburrá, con georefenciación de éstas”. Informe Agosto de 2006.
2. Sistema Estadístico de Comercio Exterior SIEX http://websiex.dian.gov.co/, Consultado marzo 15 de 2007.
3. S. Ordoñez, Hidrodecloración catalítica de compuestos alifáticos clorados, Tesis Doctoral, Universidad de Oviedo, Oviedo España, 2000.
4. S. Ordoñez, H. Sastre, F. Diez. “Catalytic hydrodechlorination of tetrachloroethylene over red mud”, J. Hazard. Mat.Vol. 81. 2003. pp. 103-114.
5. E. López, S. Ordoñez, H. Sastre, F. Diez. “Kinetic study of the gas-phase hydrogenation of aromatic and aliphatic organochlorinated compounds using a Pd/Al2O3 catalyst”, J. Hazard. Mat.Vol. 97. 2003. pp. 281-294.