title: The use of alkaline hydrolysis as a novel strategy for chloroform remediation: the feasibility of using construction wastes and evaluation of carbon isotopic fractionation.
abstract: Laboratory and field-scale pilot experiments were performed to evaluate the feasibility of chloroform degradation by alkaline hydrolysis and the potential of δ(13)C values to assess this induced reaction process at contaminated sites. In batch experiments, alkaline conditions were induced by adding crushed concrete (pH 12.33 ± 0.07), a filtered concrete solution (pH 12.27 ± 0.04), a filtered cement solution (pH 12.66 ± 0.02) and a pH 12 buffer solution (pH 11.92 ± 0.11). The resulting chloroform degradation after 28 days was 94, 96, 99, and 72%, respectively. The experimental data were described using a pseudo-first-order kinetic model, resulting in pseudo-first-order rate constant values of 0.10, 0.12, 0.20, and 0.05 d(-1), respectively. Furthermore, the significant chloroform carbon isotopic fractionation associated with alkaline hydrolysis of chloroform (-53 ± 3‰) and its independence from pH in the admittedly limited tested pH range imply a great potential for the use of δ(13)C values for in situ monitoring of the efficacy of remediation approaches based on alkaline hydrolysis. The carbon isotopic fractionation obtained at the lab scale allowed the calculation of the percentage of chloroform degradation in field-scale pilot experiments where alkaline conditions were induced in two recharge water interception trenches filled with concrete-based construction wastes. A maximum of approximately 30-40% of chloroform degradation was achieved during the two studied recharge periods. Although further research is required, the treatment of chloroform in groundwater through the use of concrete-based construction wastes is proposed. This strategy would also imply the recycling of construction and demolition wastes for use in value-added applications to increase economic and environmental benefits.
authors.affiliation: Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB) , Martí Franquès s/n, 08028. Barcelona, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Torrentó
authors.forename: Carme
authors.initials: C
authors.lastname: Audí-Miró
authors.forename: Geneviève
authors.initials: G
authors.lastname: Bordeleau
authors.forename: Massimo
authors.initials: M
authors.lastname: Marchesi
authors.forename: Mònica
authors.initials: M
authors.lastname: Rosell
authors.forename: Neus
authors.initials: N
authors.lastname: Otero
authors.forename: Albert
authors.initials: A
authors.lastname: Soler
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis; D002251:Carbon Tetrachloride / Q000737:chemistry; D005591:Chemical Fractionation; D002725:Chloroform / Q000737:chemistry*; D003252:Construction Materials; D005240:Feasibility Studies; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D014867:Water; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D014874:Water Pollutants, Chemical; D014867:Water; D002725:Chloroform; D002251:Carbon Tetrachloride