Browsing by Author "Vargas, Ignacio"

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    Energy and copper recovery from acid mine drainage by microbial fuel cells. Effect of the hydrochar doping on carbon felt anodes
    (2025) Delgado, Yelitza; Tapia, Natalia; Lopez, Ester; Llanos, Javier; Vargas, Ignacio; Fernandez-Morales, Francisco Jesus
    This work investigates the performance of a Microbial Fuel Cell (MFC) for Acid Mine Drainage (AMD) treatment using bare and hydrochar-doped carbon felt (CF) anodes. Hydrochar was synthesized through hydrothermal carbonization of Spergularia rubra, followed by activation at 500 degrees C, resulting in improved O/C and H/C ratios of 0.26 and 0.78, respectively. The study reveals that doping CF anodes with non-activated and activated hydrochar significantly enhances copper recovery and electricity generation. The highest copper recovery rate of 16.0 mg/L h- 1 was achieved with activated hydrochar-doped CF (CFaH) anodes, followed by 10.6 mg/L h- 1 with nonactivated hydrochar-doped CF (CFnaH) anodes, and 7.1 mg/L h- 1 with bare CF anodes. Hydrochar doping also improved the maximum current density to 0.21 mA cm- 2 compared to 0.16 mA cm- 2 with bare CF anodes. These results demonstrate the potential of hydrochar-doped CF anodes for efficient metal and energy recovery from AMD, offering a sustainable and energy-efficient alternative to conventional methods.
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    Marine biocorrosion inhibition of Pseudomonas sp. biofilms on 304 stainless steel coated with poly-6-aminoindole produced by two different electrochemical methods
    (2024) Castaneda, Erik; Castillo, Javiera; Pascual, Marta; Rubio, Francisca; Vargas, Ignacio; De la Iglesia, Rodrigo; Armijo, Francisco
    Forming a bacterial biofilm on a metallic surface could result in biocorrosion and biofouling development. New environmentally friendly coatings are required to protect infrastructure, especially in coastal and marine environments. This study aimed to evaluate the mitigation of biocorrosion produced by Pseudomonas sp. biofilms on AISI 304 stainless steel (SS304) coupons modified with poly-6-aminoindole (PAIn) using two electrochemical techniques: cyclic voltammetry (SS/6-PAIn CV) and chronoamperometry (SS/6-PAIn CA). Experimental trials were performed in two stages: (i) the settlement and colonization of bacteria (1 h of incubation) and (ii) biofilm development (7 days of incubation). Colonized surfaces were characterized by epifluorescence and field emission scanning electron microscopy. Biocorrosion mitigation was evaluated using linear resistance polarization, electrochemical impedance spectroscopy, and linear scanning voltammetry in simulated seawater at 20 degrees C. The results showed biofilm formation on SS304 and SS/6-PAIn CA, but in SS/6-PAIn CV, the coating considerably reduced biofilm formation, with alterations in the size and structural organization of the biofilm. The biofilm cover percentages were 31.63 %, 22.66 %, and 9.25 % for SS304, SS/6-PAIn CA, and SS/6-PAIn CV, respectively. Thus, SS/6-PAIn CV reduced biofilm growth by 70.76 % compared to bare SS after seven days of culture. Electrochemical parameters determined by LSV and EIS showed a significant improvement in charge transfer resistance and coating resistance for the SS/6-PAIn CV compared to the coating produced by chronoamperometry. Although both coatings protected the metallic surface, SS/6-PAIn CV presented the best protective properties, emerging as a promising alternative coating to mitigate the biocorrosion process of SS304 in a marine environment.
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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.