Browsing by Author "Muñoz Arango, Diana Carolina"

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    Characterization of perchlorate desorption and regeneration of the highly selective ion-exchange resin A530E using 1-butyl-3-methylimidazole chloride, 1-butyl-3-methylimidazole hydroxide, and choline chloride
    (2025) Muñoz Arango, Diana Carolina; Montaño, Diego F.; Veloso Cid, Nicolás Eduardo; Torres-Rojas, Felipe; Canales Muñoz, Roberto; Isaacs Casanova, Mauricio; Hevia, Samuel; Vargas Cucurella, Ignacio Tomás
    Perchlorate is an endocrine disruptor considered an emerging contaminant that poses risks to human health and the environment. Using selective resins is a cost-effective and reliable method for removing perchlorate from drinking water, yet regenerating these resins remains challenging. This study investigates the desorption of perchlorate from a highly selective ion-exchange resin (A530E) using 1-butyl-3-methylimidazole chloride ([Bmim][Cl]), 1-butyl-3-methylimidazole hydroxide ([Bmim][OH]), and choline chloride ([Chl][Cl]). Through three consecutive desorption cycles, [Bmim][OH] exhibited superior performance, achieving up to 23.48 mg·g−1 perchlorate desorption and recovery of nearly 22 % of the resin’s initial adsorption capacity in the second cycle, doubling the yields of the other treatments. Nevertheless, overall regeneration efficiency remained below 50 %, underscoring the need to optimize regenerative strategies. Fourier-transform infrared (FT-IR) spectroscopy indicates specific interactions between the organic salts, perchlorate, and functional groups of the resin. In contrast, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX) revealed notable changes in surface chemistry and morphology upon desorption. This study demonstrates that the ionic liquids used here can be effective desorption agents for removing perchlorate loaded from resins, thus offering a pathway for applying alternative solutions in water treatment.
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    Desorption, regeneration and bioreduction of perchlorate with organic salts [Bmim][Cl], [Bmim][OH] and [Chl][Cl] in ion exchange resins
    (2024) Muñoz Arango, Diana Carolina; Vargas Cucurella, Ignacio Tomás; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    In the world, approximately two billion people live under water stress. In Latin America and the Caribbean, water quality is often poor due to the presence of natural or anthropogenic contaminants. Emerging pollutants (ECs) can negatively affect the environment or human health. In Chile, the soils of the Atacama Desert are the most extensive natural perchlorate reservoirs in the world, directly impacting the composition of drinking water sources in northern Chile. This study addresses the problem of two oxyanions, specifically perchlorate and chlorate, in the drinking water of northern Chilean cities, in the Atacama Desert area. The use of organic salts as an intermediate for perchlorate desorption and regeneration of a highly selective resin for perchlorate was studied. The findings of perchlorate bioreduction in organic salts brines are promising even without adding external carbon sources and electron donors. This study highlights the need to establish systematic monitoring, regulation, and treatment of these ECs in drinking water sources. This study opens the possibility of continuing to investigate the use of organic salts to recove compounds of interest, while extending the useful life of materials such as ion exchange resins.
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    Perchlorate and chlorate assessment in drinking water in northern Chilean cities
    (2023) Muñoz Arango, Diana Carolina; Torres Rojas, Felipe Ernesto; Tapia Flores, Natalia F.; Vega Muñoz, Marcela Natalia; Alvear, Cristóbal; Pizarro, Gonzalo; Pastén González, Pablo Arturo; Cortés Arancibia, Sandra; Vega Contreras, Alejandra Soledad; Calderón, Raúl; Nerenberg, Robert; Vargas, Ignacio; CEDEUS (Chile)
    Perchlorate and chlorate are endocrine disruptors considered emerging contaminants (ECs). Both oxyanions are commonly associated with anthropogenic contamination from fertilizers, pesticides, explosives, and disinfection byproducts. However, the soils of the Atacama Desert are the most extensive natural reservoirs of perchlorate in the world, compromising drinking water sources in northern Chile. Field campaigns were carried (2014–2018) to assess the presence of these ECs in the water supply networks of twelve Chilean cities. Additionally, the occurrence of perchlorate, chlorate and other anions typically observed in drinking water matrices of the Atacama Desert (i.e., nitrate, chloride, sulfate) was evaluated using a Spearman correlation analysis to determine predictors for perchlorate and chlorate. High concentrations of perchlorate (up to 114.48 μg L−1) and chlorate (up to 9650 μg L−1) were found in three northern cities. Spatial heterogeneities were observed in the physicochemical properties and anion concentrations of the water supply network. Spearman correlation analysis indicated that nitrate, chloride, and sulfate were not useful predictors for the presence of perchlorate and chlorate in drinking water in Chile. Hence, this study highlights the need to establish systematic monitoring, regulation, and treatment for these EC of drinking water sources in northern Chilean cities for public health protection.
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    Synergistic effect of electrotrophic perchlorate reducing microorganisms and chemically modified electrodes for enhancing bioelectrochemical perchlorate removal
    (2023) Torres Rojas, Felipe Ernesto; Muñoz Arango, Diana Carolina; Canales, Camila Pía; Hevia, Samuel A.; Leyton Soto, Felipe Arturo; Veloso Cid, Nicolás Eduardo; Isaacs Casanova, Mauricio; Vargas Cucurella, Ignacio Tomás; CEDEUS (Chile)
    Perchlorate has been described as an emerging pollutant that compromises water sources and human health. In this study, a new electrotrophic perchlorate reducing microorganism (EPRM) isolated from the Atacama Desert, Dechloromonas sp. CS-1, was evaluated for perchlorate removal in water in a bioelectrochemical reactor (BER) with a chemically modified electrode. BERs were operated for 17 days under batch mode conditions with an applied potential of −500 mV vs. Ag/AgCl. Surface analysis (i.e., SEM, XPS, FT-IR, RAMAN spectroscopy) on the modified electrode demonstrated heterogeneous transformation of the carbon fibers with the incorporation of nitrogen functional groups and the oxidation of the carbonaceous material. The BERs with the modified electrode and the presence of the EAM reached high cathodic efficiency (90.79 ± 9.157%) and removal rate (0.34 ± 0.007 mol m−3-day) compared with both control conditions. The observed catalytic enhancement of CS-1 was confirmed by a reduction in the charge transfer resistance obtained by electrochemical impedance spectroscopy (EIS). Finally, an electrochemical kinetic study revealed an eight-electron perchlorate bioreduction reaction at −638.33 ± 24.132 mV vs. Ag/AgCl. Therefore, our results show the synergistic effect of EPRM and chemically modified electrodes on perchlorate removal in a BER.