Fernández Reyes, Bethzaely

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    Hierarchical porous carbon-zeolite composites materials for the adsorption of contaminants of emerging concern from water
    (2021-03-23) Fernández Reyes, Bethzaely; Hernández Maldonado, Arturo J.; College of Engineering; Martínez Iñesta, María; Méndez Román, Rafael; Suleiman Rosado, David; Department of Chemical Engineering; Calcagno, Bárbara O.
    The steady and unnoticed rise of contaminants of emerging concern (CECs) into different water sources results in a tremendous challenge regarding its efficient, systematic, and coherent mitigation. Its recalcitrant presence, and in some cases the potential hazard to human health and/or the ecosystem complicates this vexing issue, leading towards particular attention from the scientific community worldwide. The different forms of ingestion, their occurrence in low concentrations, the season variability, and their ease of translocation hinder these molecules’ fate and further elimination. Adsorption is recognized among the used technologies for CEC mitigation as a separation process that might be achieved in the absence of high energy inputs or the undesired production of harmful compounds to water matrices. In addition to being a cost-effective process and relatively easy to implement in existing water treatment facilities, this technology allows for the selective and efficient CEC capture when the porous adsorbent design is tailored using a bottom-up approach. This work demonstrates that a suitable porous composite design, combining a carbon and zeolite source, might tackle CECs removal selectively by imparting a synergistic combination even at low parts per million and parts per billion levels. The former, well-known for its hydrophobic character, lacks selectivity, while the latter holds flexible surface chemistry that allows easy functionalization despite exhibiting limited hydrophobicity. The combination of these materials was achieved via hydrothermal crystallization by means of seed growing technique of the zeolite within the porous system of two carbon sources (an amorphous activated carbon (AC) and a three-dimensionally ordered mesoporous carbon (3DOm)). With the intention to provide strong electronic fields, the zeolitic portion was modified with copper(II) cations to take advantage of the coordination complex type interactions through the electron donation and back-donation with the aromatic rings and/or functional groups of the CEC at ambient conditions. It was shown that the bottom-up approach used through the confinement of the copper(II) functionalized zeolite overcomes the individual limitations of each constituent, achieving a synergistic effect. The performance of these hybrid materials was evaluated by adsorption of different compounds (i.e., caffeine, carbamazepine, naproxen) and metabolites (i.e., salicylic acid, clofibric acid, paraxanthine, 10,11-epoxy-carbamazepine, o-desmethyl-naproxen) from aqueous solutions containing the pollutants in single- and multi-component system via batch and fixed-bed studies. These tests revealed a greater adsorption capacity and selectivity towards anionic products, especially onto the variant containing the transition metal. Similarly, the presence of multiple components in the water matrix generated a competition effect towards the active sites and decreased their respective adsorption capacities. However, the modified materials exhibited less competition than their unmodified counterparts or the individual constituents of these hybrid adsorbents, due to the strong metal presence and more adsorption sites available to interact with the CECs. Finally, this work confirms that the hierarchical design of porous materials can be strategically tailored to create adsorbents with robust platforms capable of being tunable aiming to separate and capture particular CECs.
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    Hierarchical three-dimensionally ordered mesoporous carbon (3DOm) zeolite composites for the adsorption of Contaminants of emerging concern
    (Elsevier Inc., 2021-02-12) Fernández Reyes, Bethzaely; Morales Jiménez, Stefannie; Sánchez Marrero, Gloriani; Muñoz Senmache, Juan C; Hernández Maldonado, Arturo J; College of Engineering; Department of Chemical Engineering
    Effective removal of contaminants of emerging concern (CECs) from water via adsorption requires adsorbent materials that showcase a synergistic combination of textural properties, hydrophobicity, and specific surface interactions. In this work, we present a hierarchical composite prepared on the basis of in-situ or confined growth of a faujasite zeolite (FAU) within the voids of a 3D mesoporous ordered carbon (3DOm). This adsorbent was tested for the removal of several CECs (i.e., caffeine, carbamazepine, naproxen and metabolites clofibric acid, 10,11-epoxycarbamazepine, o-desmethyl naproxen, paraxanthine, and salicylic acid) from water at ambient conditions. Upon inclusion of copper(II) extra-framework cations, the hierarchical composite (Cu-3DOm-FAU) excelled at adsorbing ionic CECs and offered similar uptake capacity toward neutral parent compounds in both single- and multicomponent fashion and while covering a mg L^-1 - mg L^-1 concentration range. Compared to other adsorbents reported so far in the literature, the Cu-3DOm-FAU composite adsorption capacities were larger, in many cases by at least one order of magnitude. Given the substantial thermal stability of the composite, regeneration could be accomplished via thermal cycling also depending on the type of CEC involved.