Estudio de la degradación de alaclor y atrazina en muestras sintéticas

Abstract

Atrazine and alachlor are chlorinated pesticides commonly used in crops of sugar cane and corn in Ecuador. Since these pesticides are persistent in the environment and exhibit slow rates of degradation, the degradation of the chlorinated pesticides through traditional Fenton and Fenton modified with EDTA and UV light, in synthetics samples in water (25 ppm of atrazine and 60 ppm of alachlor) was studied. Pseudo first order kinetics for the removal of atrazine and alachlor was confirmed. Four molar ratios H2O2:Fe2+ were tested for the traditional Fenton and with the best conditions (95,5:1), a 98,60 % removal of atrazine and 99,70 % removal of alaclor with 90 minutes of treatment were achieved. Two chelation molar ratios (1:1 and 2:1) were tested to create the complex EDTA-Fe2+. The best ratio (1:1) allowed a 90,24 % removal of atrazine and a value of alachlor under the limit of detection of the method (LOD alaclor=0,06 ppm) within 60 minutes. The addition of UV light to the modified Fenton increased the reaction kinetics constants for the removal of atrazine in 17 times and 11 times for the removal of alachlor.