Héctor Valdés

Summary

Country: Chile

Publications

  1. ncbi Methylene blue removal from contaminated waters using heterogeneous catalytic ozonation promoted by natural zeolite: mechanism and kinetic approach
    H Valdes
    Laboratorio de Tecnologías Limpias F Ingeniería, Universidad Católica de la Santísima Concepción, Chile
    Environ Technol 33:1895-903. 2012
  2. doi Natural zeolite reactivity towards ozone: the role of compensating cations
    Héctor Valdés
    Laboratorio de Tecnologías Limpias F Ingeniería, Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepcion, Chile
    J Hazard Mater 227:34-40. 2012
  3. doi BTX abatement using Chilean natural zeolite: the role of Brønsted acid sites
    S Alejandro
    Universidad Católica de la Santísima Concepción, Concepcion, Chile
    Water Sci Technol 66:1759-65. 2012
  4. ncbi Heterogeneous catalytic ozonation of cationic dyes using volcanic sand
    H Valdes
    Clean Technology Laboratory, Catholic University of Concepcion, Alonso de Ribera 2850, Concepcion, Chile
    Water Sci Technol 61:2973-8. 2010
  5. doi Catalytic ozone aqueous decomposition promoted by natural zeolite and volcanic sand
    Héctor Valdés
    Departamento de Ingeniería Industrial F Ingeniería, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    J Hazard Mater 165:915-22. 2009
  6. ncbi Heterogeneous catalytic ozonation of benzothiazole aqueous solution promoted by volcanic sand
    H Valdes
    Facultad de Ingenieria, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    J Hazard Mater 153:1036-42. 2008
  7. ncbi Heterogeneous and homogeneous catalytic ozonation of benzothiazole promoted by activated carbon: kinetic approach
    Héctor Valdés
    Facultad de Ingenieria, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    Chemosphere 65:1131-6. 2006
  8. ncbi Ozonation of benzothiazole saturated-activated carbons: influence of carbon chemical surface properties
    H Valdes
    Facultad de Ingenieria, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    J Hazard Mater 137:1042-8. 2006
  9. doi Methylene blue removal from contaminated waters using O3, natural zeolite, and O3/zeolite
    H Valdes
    Facultad de Ingenieria, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    Water Sci Technol 60:1419-24. 2009
  10. ncbi Advanced treatment of benzothiazole contaminated waters: comparison of O3, AC, and O3/AC processes
    H Valdes
    Chemical Eng Dept, University of Concepcion, P O Box 160 C, Correo 3, Concepcion, Chile
    Water Sci Technol 52:281-8. 2005

Collaborators

  • Serguei Alejandro
  • S Alejandro
  • Claudio A Zaror
  • Marie Helene Manero
  • M H Manero
  • C A Zaror

Detail Information

Publications12

  1. ncbi Methylene blue removal from contaminated waters using heterogeneous catalytic ozonation promoted by natural zeolite: mechanism and kinetic approach
    H Valdes
    Laboratorio de Tecnologías Limpias F Ingeniería, Universidad Católica de la Santísima Concepción, Chile
    Environ Technol 33:1895-903. 2012
    ..The increase in methylene blue removal rate could be related to ozone interaction with hydroxyl groups present on the zeolite surface (S--OH2(+), S--OH, S--O(-)), which plays a key role in the reaction mechanism...
  2. doi Natural zeolite reactivity towards ozone: the role of compensating cations
    Héctor Valdés
    Laboratorio de Tecnologías Limpias F Ingeniería, Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepcion, Chile
    J Hazard Mater 227:34-40. 2012
    ..Weak and strong Lewis acid sites of zeolite surface are identified here as the main active sites responsible of ozone removal...
  3. doi BTX abatement using Chilean natural zeolite: the role of Brønsted acid sites
    S Alejandro
    Universidad Católica de la Santísima Concepción, Concepcion, Chile
    Water Sci Technol 66:1759-65. 2012
    ..The presence of humidity has a negative effect on zeolite adsorption capacity. Natural zeolites could be an interesting option for benzene, toluene and xylene vapour emission abatement...
  4. ncbi Heterogeneous catalytic ozonation of cationic dyes using volcanic sand
    H Valdes
    Clean Technology Laboratory, Catholic University of Concepcion, Alonso de Ribera 2850, Concepcion, Chile
    Water Sci Technol 61:2973-8. 2010
    ..The results obtained here indicate the importance of chemical surface properties on methylene blue oxidation reactions, suggesting that acid surface sites of volcanic sand play a key role on the reaction mechanism...
  5. doi Catalytic ozone aqueous decomposition promoted by natural zeolite and volcanic sand
    Héctor Valdés
    Departamento de Ingeniería Industrial F Ingeniería, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    J Hazard Mater 165:915-22. 2009
    ..The presence of metal oxides in zeolite and volcanic sand might catalyse ozone decomposition into more active radicals, thus enhancing the oxidation of organic pollutant...
  6. ncbi Heterogeneous catalytic ozonation of benzothiazole aqueous solution promoted by volcanic sand
    H Valdes
    Facultad de Ingenieria, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    J Hazard Mater 153:1036-42. 2008
    ..Moreover, the inhibitory effect of free radical scavengers is also impaired by volcanic sand, suggesting that strong Lewis acid surface sites play a key role on the reaction mechanism...
  7. ncbi Heterogeneous and homogeneous catalytic ozonation of benzothiazole promoted by activated carbon: kinetic approach
    Héctor Valdés
    Facultad de Ingenieria, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    Chemosphere 65:1131-6. 2006
    ..A simplified mechanism and a kinetic scheme representing the contribution of homogeneous and heterogeneous reactions on BT ozonation in the presence of activated carbon is proposed...
  8. ncbi Ozonation of benzothiazole saturated-activated carbons: influence of carbon chemical surface properties
    H Valdes
    Facultad de Ingenieria, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    J Hazard Mater 137:1042-8. 2006
    ..Oxidation of BT adsorbed on activated carbon seemed to occur via both direct reaction with ozone molecules, and by oxygen radical species generated by catalytic ozone decomposition on metallic surface sites...
  9. doi Methylene blue removal from contaminated waters using O3, natural zeolite, and O3/zeolite
    H Valdes
    Facultad de Ingenieria, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepcion, Chile
    Water Sci Technol 60:1419-24. 2009
    ....
  10. ncbi Advanced treatment of benzothiazole contaminated waters: comparison of O3, AC, and O3/AC processes
    H Valdes
    Chemical Eng Dept, University of Concepcion, P O Box 160 C, Correo 3, Concepcion, Chile
    Water Sci Technol 52:281-8. 2005
    ....
  11. ncbi Kinetic study of reactions between ozone and benzothiazole in water
    H Valdes
    Chemical Engineering Department, University of Concepcion, P O Box 160 C, Correo 3, Concepcion, Chile
    Water Sci Technol 48:505-10. 2003
    ..3 mol l(-1) s(-1) and kI = 6 x 10(9) mol l(-1) s(-1), respectively. The free radical mechanism accounted for 83-96% of BT removal rate within the pH range 2-9, at 20 degrees C...
  12. ncbi Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: the influence of zeolite chemical surface characteristics
    Serguei Alejandro
    Laboratorio de Tecnologías Limpias F Ingeniería, Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepcion, Chile Núcleo de Energías Renovables F Ingeniería, Universidad Católica de Temuco, Rudecindo Ortega 02950, Temuco, Chile
    J Hazard Mater 274:212-20. 2014
    ..Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity. ..