SciELO - Scientific Electronic Library Online

 
vol.38 número5Aerobic biotransformation of 2, 4, 6-trichlorophenol by Penicillium chrysogenum in aqueous batch culture: degradation and residual phytotoxicityNatural organic matter (NOM) in South African waters: NOM characterisation using combined assessment techniques índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados

Articulo

Indicadores

Links relacionados

  • En proceso de indezaciónCitado por Google
  • En proceso de indezaciónSimilares en Google

Compartir


Water SA

versión On-line ISSN 0378-4738

Resumen

BAMUZA-PEMU, Emomotimi E  y  CHIRWA, Evans MN. Photocatalytic degradation of geosmin: reaction pathway analysis. Water SA [online]. 2012, vol.38, n.5, pp. 689-696. ISSN 0378-4738.

The presence of geosmin in drinking water imparts a musty odour which leads to consumer complaints. Geosmin and other unwanted organics can be treated using photocatalysis. However, the intermediates formed during the photocatalytic degradation process and their degradation pathways have not previously been described. In this study, the degradation profile, as well as the intermediates formed during the photocatalytic degradation of geosmin was monitored in an effort to obtain a better understanding of the degradation kinetics and pathway. Photocatalytic degradation of geosmin in the presence of radical scavengers was shown to be inhibited, as evidenced by the reduction in reaction rate coefficient (k') from 0.055 to 0.038 min"1. The hydroxyl radical reaction was thus shown to be the predominant process over direct photolysis by incident UV energy. Results from mass spectrum analysis of degradation intermediates indicate rapid fission of sp3l-sp3 (Cl-C) bonds resulting in ring opening of the cyclic geosmin structure. Bicyclic compounds that could be expected from dehydration and dehydrogenation of geosmin's ringed structure were not found among the detected intermediate products. Intermediates identified consisted of acyclic unsaturated alkenes, carbonyl compounds and some organic acids. Although the identified degradation products are not seen to be directly harmful, chlorine disinfection of water containing these compounds could produce potentially harmful halogenated hydrocarbons.

Palabras clave : photocatalysis; geosmin; 2-methylisoborneol (2-MIB); taste and odour; degradation intermediates.

        · texto en Inglés     · Inglés ( pdf )