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Author(s): Cátia Oliveira
K. Gruskevica
T. Juhna
K. Tihomirova
Arminda Alves
Luís Madeira
Title: Removal of paraquat pesticide with Fenton reaction in a pilot scale water system
Issue Date: 2014
Abstract: Advanced oxidation processes, such as the Fenton's reagent, are powerful methods for decontamination of different environments from recalcitrant organics. In this work, the degradation of paraquat (PQ)pesticide was assessed (employing the commercial product gramoxone) directly inside the pipes of a pilotscale loop system; the effect of corroded cast iron pipe and loose deposits for catalysing the process wasalso evaluated. Results showed that complete degradation of paraquat ([PQ]0 = 3.9 × 10−4 M, T = 20-30 ◦C,pH0 = 3, [H2O2]0 = 1.5 × 10−2 M and [Fe (II)] = 5.0 × 10−4 M,) was achieved within 8 h, either in lab scale orin the pilot loop. Complete PQ degradation was obtained at pH 3 whereas only 30 % of PQ was degraded atpH 5 during 24 h. The installation of old cast iron segments with length from 0.5 to 14 m into PVC pipe loopsystem had a significant positive effect on degradation rate of PQ, even without addition of iron salt; the longerthe iron pipes section, the faster was the pesticide degradation. Addition of loose deposits (mostly corrosionproducts composed of goethite, magnetite and a hydrated phase of FeO) also catalysed the Fenton reactiondue to presence of iron in the deposits. Moreover, gradual addition of hydrogen peroxide improved gramoxone degradation and mineralization. This study showed for the first time that is possible to achieve completedegradation of pesticides in situ pipe water system and that deposits and corroded pipes catalyse oxidation ofpesticides.
Subject: Ciências da engenharia e tecnologias
Engineering and technology
Scientific areas: Ciências da engenharia e tecnologias
Engineering and technology
Related Information: info:eu-repo/grantAgreement/COMISSÃO EUROPEIA/7.º Programa-Quadro de IDT/217976 /Security and decontamination of drinking water distribution systems following a deliberate contamination /SECUREAU
info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projectos de I&DT em Todos os Domínios Científicos/PTDC/AAC-AMB/101687/2008/Segurança química em sistemas de abastecimento de água/ACQUASAFE
Document Type: Artigo em Revista Científica Internacional
Rights: openAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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