Resumen

VASQUEZ, Esmeralda; PENUELA, Gustavo  y  AGUDELO, Sergio. Chlorothalonil photodegradation study using Fenton and photocathalysis techniques with titanium dioxide by means of solar radiation. Rev.fac.ing.univ. Antioquia [online]. 2010, n.51, pp.105-113. ISSN 0120-6230.

For the design of wastewater treatment systems it is required to determine the degradation time of the pollutants to scale, and with said information the residence time of the water in the selected treatment can be calculated. In treatment systems with solar collectors, the photodegradation time of the pollutant will depend on the intensity of the solar radiation, which varies with the time of day, and the environmental conditions. In this research work the photodegradation of the pesticide Chlorothalonil with titanium dioxide and with Fenton reactive, respectively, was evaluated using a solar collector. The experiments were carried out in the city of Medellín (6^o North latitude, 1570 meters above sea level, m.s.l.). 95% of the Chlorothalonil degradation was reached with 500 mg/l TiO₂ and 1,0 mg/l sodium persulfate in 4 h of solar irradiation, with an accumulated energy of 15,1 kJ/l. The same percentage was reached with 10 mg/l ferric ion in 18 hours of solar irradiation with an accumulated energy of 38 kJ/l. The degradation kinetics was first order with both treatment techniques, but a higher degradation constant and a higher mineralization degree (80%) was obtained with titanium dioxide compared with photofenton (72%). The organic compounds mineralization (Chlorothalonil and degradation subproducts) was verified by the disappearance of the total organic carbon (TOC) and the chlorides and nitrates formation. Six degradation products were detected, and in spite of their low concentration, they can be responsible of the high toxicity of the final effluent in the bioassays with Dapnhia pulex.

Palabras clave : Photofenton; photocatalysis; UV radiation; pesticides; advanced oxidation.

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