title: Organic micropollutants (OMPs) oxidation by ozone: Effect of activated carbon on toxicity abatement.
abstract: Oxidation and removal of organic micropollutants (OMPs) on ultrapure (UPW) and natural water (NW) by ozone (O3) and ozone/powdered activated carbon (O3/PAC) have been studied. The OMPs atrazine (ATZ, herbicide), carbamazepine (CBZ, anticonvulsant), diclofenac (DCL, anti-inflammatory) and triclosan (TCS, antimicrobial) are incorporated continuously and uncontrolled on water treatment systems (e.g., drinking water treatment plants, wastewater treatment plants). Batch experiments on ultrapure and natural water showed that ATZ treated with O3and O3/PAC has the slowest transformation rate (>90% at 30min reaction) while CBZ, DCL and TCS were oxidized very fast (>90% at ~5min). The radical scavenger tert-Butyl alcohol (TBA) was used to evaluate the contribution of HO on the OMPs oxidation. TBA, a hydrophilic compound with low adsorbability, was used as a strong HO scavenger to assess the role of the OH radical in the oxidation of the OMPs studied. ATZ oxidation was mainly driven by OH radicals. On the contrary, CBZ, DCL and TCS were removed by direct reaction with ozone. Infrared analysis (FTIR) showed changes in the PAC surface functional groups of the carbon exposed to ozone, decreasing its basic properties. The acute toxicity assays of the OMPs mixture dissolved in UPW performed with D. magna was significantly reduced by ozonation. The addition of PAC to the ozonation process, strongly improved the acute toxicity removal. Short chain mono- and di-carboxylic acids were identified as some of the oxidation intermediates formed during ozone treatment.
authors.affiliation: Facultad de Ciencias Ambientales, Universidad de Concepción, Concepción, Chile; Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepción, Concepción, Chile; Facultad de Ciencias Químicas, Universidad de Concepción, Concepción, Chile. Electronic address: orozas@udec.cl.
authors.forename: Oscar
authors.initials: O
authors.lastname: Rozas
authors.affiliation: Facultad de Ciencias Ambientales, Universidad de Concepción, Concepción, Chile; Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepción, Concepción, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Baeza
authors.affiliation: Facultad de Ciencias Ambientales, Universidad de Concepción, Concepción, Chile; Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepción, Concepción, Chile.
authors.forename: Katherine
authors.initials: K
authors.lastname: Núñez
authors.affiliation: Centro de Biotecnología, Universidad de Concepción, Chile.
authors.forename: Alfred
authors.initials: A
authors.lastname: Rossner
authors.affiliation: Facultad de Ciencias Ambientales, Universidad de Concepción, Concepción, Chile; Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepción, Concepción, Chile.
authors.forename: Roberto
authors.initials: R
authors.lastname: Urrutia
authors.affiliation: Facultad de Ciencias Químicas, Universidad de Concepción, Concepción, Chile. Electronic address: hmansill@udec.cl.
authors.forename: Héctor D
authors.initials: HD
authors.lastname: Mansilla
keywords: Activated carbon; Advanced oxidation process; Daphnia magna; Emerging contaminants; Organic micropollutants; Ozone