Person: Montero González, Esperanza
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First Name
Esperanza
Last Name
Montero González
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Geodinámica, Estratigrafía y Paleontología
Area
Geodinámica Externa
Identifiers
2 results
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Item Methanol-enhanced degradation of carbon tetrachloride by alkaline activation of persulfate: kinetic model(Science of The Total Environment, 2019) Domínguez Torre, Carmen María; Rodriguez, Vanesa; Montero González, Esperanza; Romero Salvador, Arturo; Santos López, AuroraCarbon tetrachloride (CT), a chlorinated organic compound widely used in the chemical industry during the 20th century, is nowadays a ubiquitous contaminant in groundwater and in situ technologies for its destruction are required. In this work, the degradation of CT by the alkaline activation of persulfate (PS) has been studied. Among the pool of radical species generated (hydroxyl radicals, sulfate radicals and superoxide radicals), O2∙− resulted to be the only species responsible for CT abatement. It has been found that the presence of other solvents less polar than water (hydrogen peroxide, acetone, propanol and methanol) improves CT degradation. Among them, methanol was selected as the most adequate co-solvent, leading to the complete elimination of CT (100 mg L−1, 24 h) with a moderate unproductive consumption of the oxidant. The degradation of CT increased proportionally with the concentration of this solvent (from 0.1 to 10 g L−1). The ratio NaOH:PS (from 1 to 8) did not affect the degradation of CT when working with a constant concentration of PS and highly alkaline conditions were maintained. The removal rate of CT increased as the concentration of PS increased (from 20 to 60 g L−1), while the conversion of this pollutant did not depend on its initial concentration (from 10 to 100 mg L−1). A kinetic model that considers the concentration of PS, MeOH and CT and can predict the concentration of CT with reaction time at different operating conditions, has been developed from the experimental data.Item Abatement of Dichloromethane using Persulfate Activated by Alkali: a kinetic study(Separation and Purification Technology, 2020) Domínguez Torre, Carmen María; Rodriguez, Vanesa; Montero González, Esperanza; Romero Salvador, Arturo; Santos López, AuroraThe alkaline activation of persulfate (PS) has been tested in this study as in situ oxidation technology for the abatement of dichloromethane (DCM), a chlorinated volatile organic pollutant commonly found in groundwater due to its wide use as solvent in the chemical industry during the last decades. The addition of an alkali (NaOH) as persulfate activator generates hydroxyl and superoxide radicals, achieving the total degradation of the pollutant (XDCM = 99%, 96 h, CDCM = 1.2 mmol L−1, CPS = 42 mmol L−1, CNAOH = 169 mmol L−1). From the results obtained in the presence of a hydroxyl radical-scavenger (methanol, CMeOH = 313 mmol L−1), it has been concluded that only hydroxyl radicals are responsible of DCM abatement. Trichloroethylene was identified as intermediate compound and formic acid and chloride as degradation products. The conversion of DCM increased as the initial concentration of the pollutant decreased (from 1.2 mmol L−1 to 0.1 mmol L−1), whereas an increase in the oxidant concentration (from 8 to 168 mmol L−1) led to an increase in the degradation rate of the pollutant. Finally, the molar ratio NaOH:PS (in the range 1–4) did not affect the degradation of the pollutant when a pH high enough (>12) was maintained. A kinetic model, able to predict adequately the experimental DCM concentration profiles as a function of the concentration of DCM, PS and NaOH, has been developed. The kinetic model discriminated was zero order, first order and hyperbolic order for NaOH, PS and DCM concentration, respectively.