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Photocatalytic degradation of imazethapyr herbicide at TiO2/H2O interface.
Chemosphere. 2005 Mar; 58(10):1461-9.C

Abstract

The photocatalytic degradation of imazethapyr, a herbicide of the imidazolinone family, was investigated in an aqueous suspension of titanium dioxide used as a catalyst. A pseudo-first order kinetic model was employed to discuss the results. The effect of catalyst loading, initial concentration of imazethapyr, hydrogen peroxide, pH value, and temperature were investigated. Imazethapyr disappearance as a function of irradiation time was analyzed by HPLC. The ammonium ion formation was determined spectrophotometrically at 694 nm. The degradation was observed to proceed more favorably at natural pH (ca. 4.4) when the pH was varied in the range from 2 to 11. The addition of hydrogen peroxide to the TiO2 suspension enhanced the degradation rate constant up to 5.0x10(-3) mol l-1, but decreased it at higher concentrations. The degradation rate constants decreased by 19% with a temperature increase from 20 to 40 degrees C in the TiO2 suspension, whereas a 16% increase in imazethapyr direct photolysis was observed for the same temperature range. This behavior indicates the occurrence of physisorption between TiO2 and imazethapyr molecules.

Authors+Show Affiliations

Departamento de Química, CCE, Universidade Estadual de Londrina, Caixa postal 6001, 86051-990 Londrina, PR, Brazil.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15686765

Citation

Rumi Ishiki, Renata, et al. "Photocatalytic Degradation of Imazethapyr Herbicide at TiO2/H2O Interface." Chemosphere, vol. 58, no. 10, 2005, pp. 1461-9.
Rumi Ishiki R, Mitsugu Ishiki H, Takashima K. Photocatalytic degradation of imazethapyr herbicide at TiO2/H2O interface. Chemosphere. 2005;58(10):1461-9.
Rumi Ishiki, R., Mitsugu Ishiki, H., & Takashima, K. (2005). Photocatalytic degradation of imazethapyr herbicide at TiO2/H2O interface. Chemosphere, 58(10), 1461-9.
Rumi Ishiki R, Mitsugu Ishiki H, Takashima K. Photocatalytic Degradation of Imazethapyr Herbicide at TiO2/H2O Interface. Chemosphere. 2005;58(10):1461-9. PubMed PMID: 15686765.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Photocatalytic degradation of imazethapyr herbicide at TiO2/H2O interface. AU - Rumi Ishiki,Renata, AU - Mitsugu Ishiki,Hamilton, AU - Takashima,Keiko, PY - 2003/10/27/received PY - 2004/08/05/revised PY - 2004/09/29/accepted PY - 2005/2/3/pubmed PY - 2005/5/3/medline PY - 2005/2/3/entrez SP - 1461 EP - 9 JF - Chemosphere JO - Chemosphere VL - 58 IS - 10 N2 - The photocatalytic degradation of imazethapyr, a herbicide of the imidazolinone family, was investigated in an aqueous suspension of titanium dioxide used as a catalyst. A pseudo-first order kinetic model was employed to discuss the results. The effect of catalyst loading, initial concentration of imazethapyr, hydrogen peroxide, pH value, and temperature were investigated. Imazethapyr disappearance as a function of irradiation time was analyzed by HPLC. The ammonium ion formation was determined spectrophotometrically at 694 nm. The degradation was observed to proceed more favorably at natural pH (ca. 4.4) when the pH was varied in the range from 2 to 11. The addition of hydrogen peroxide to the TiO2 suspension enhanced the degradation rate constant up to 5.0x10(-3) mol l-1, but decreased it at higher concentrations. The degradation rate constants decreased by 19% with a temperature increase from 20 to 40 degrees C in the TiO2 suspension, whereas a 16% increase in imazethapyr direct photolysis was observed for the same temperature range. This behavior indicates the occurrence of physisorption between TiO2 and imazethapyr molecules. SN - 0045-6535 UR - https://www.unboundmedicine.com/medline/citation/15686765/Photocatalytic_degradation_of_imazethapyr_herbicide_at_TiO2/H2O_interface_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0045-6535(04)00909-9 DB - PRIME DP - Unbound Medicine ER -