Browsing by Author "Torres-Rojas, Felipe"

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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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    Electrotrophic perchlorate reduction by a psychrotolerant acidophile isolated from an acid rock drainage in Antarctica
    (Elsevier Science SA, 2023) Torres-Rojas, Felipe; Hernández, Pedro; Vargas Barrios, Tomás Ignacio; Nancucheo, Iván; CEDEUS (Chile)
    A new extremophilic isolate (USS-CCA7) was obtained from an acidic environment (pH -3.2) in Antarctica phylogenetically related to Acidithiobacillus ferrivorans; its electrotrophic capacities were evaluated in a three-electrode electrochemical cell. Cyclic voltammetry showed cathodic peaks of-428 mV,-536 mV, and-634 mV (vs. Ag/AgCl; pH = 1.7; 3 M KCl) for nitrate, oxygen, and perchlorate, respectively. The catalytic role of this microorganism was also observed by a decrease in the charge transfer resistance registered via electrochemical impedance spectroscopy. Five-day chronoamperometry of culture at pH = 1.7, USS-CCA7 showed a perchlorate removal rate of 19.106 +/- 1.689 mgL-1 day-1 and a cathodic efficiency of 112 +/- 5.2 %. Growth on electrodes was observed by epifluorescence and scanning electron microscopy. Interestingly, the results showed that toward higher pH, the cathodic peak of perchlorate is reduced in the voltammetric profiles. This study highlights the use of this psychrotolerant acidophile for the bioremediation of harsh perchlorate-pressured terrestrial under acidic conditions.