ELIMINACIÓN DEL HERBICIDA 2,4-D MEDIANTE FOTÓLISIS SOLAR DE PERÓXIDO DE HIDRÓGENO Y FOTO-FENTON SOLAR CON CONCENTRACIONES DE Fe(III) SIMILARES A LAS ENCONTRADAS EN AGUA SUPERFICIAL

ANNA SERRA CLUSELLAS; LAURA DE ANGELIS; LILIANA BERTINI; MARIA M. FIDALGO DE CORTALEZZI; LUIS R PIZZIO; JULIAN ANDRES RENGIFO-HERRERA

Córdoba

Congreso; VI Congreso SETAC ARG 2016 Córdoba, Argentina; 2016

Solar Hydrogen Peroxide Photolysis (photo-peroxidation) and solar photo-Fenton using minute Fe(III) concentrations were investigated to remove the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and its main oxidation byproduct, 2,4-dichlorophenol (DCP), from Milli-Q and simulated surface water. The abatement of 1 mg L-1 2,4-D was studied by adding H2O2 (3, 6, 10 and 20 mg/L) to water with or without the presence of small concentrations of Fe(III) (≤ 0.6 mg/L) at pH 3.6 and 7.0. The natural sunlight was used as sources of irradiation. When Milli-Q water was used as matrix, results showed similar 2,4-D degradation kinetics during the first 3-4 h of treatment at neutral pH with or without the Fe(III) presence. This indicated that UV-B+A induced H2O2 photolysis process was the main responsible for 2,4-D oxidation at pH 7.0 when solar light was used as irradiation source. Acidification of the water implied the increase on 2,4-D degradation and organic matter removal efficiencies. With a simulated surface water matrix, 1 mg L-1 2,4-D as well as 2,4-DCP were completely degraded after 30 min of treatment by adding 20 mg/L H2O2 and 0.6 mg/L Fe(III) at pH 3.6, whereas 150 min were needed when 0.05 mg L-1 of total iron was present at the end of the process. At neutral pH, 2,4-D degradation kinetics was diminished mainly due to the scavenger effect of inorganic anions, achieving around 40% of elimination after 6 h of treatment.