Browsing by Author "Ferrer, Victor"

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    Ammonia Removal in Activated Carbons Prepared from Olive Oil Industry Waste
    (2023) Ferrer, Victor; Flores, Mauricio; Grandon, Hector; Escatona, Nestor; Segura, Cristina
    Activated carbons (ACs) from olive stone were prepared using CO2, steam, KOH, and H3PO4 as activating agents. The resultant activated carbons were characterized by proximate and ultimate analysis, N2 adsorption (Brunauer-Emmett-Teller (BET) method), iodine number, Boehm titration, temperature-programmed desorption (TPD), and Fourier transform infrared spectroscopy (FTIR). Ammonia (NH3) was used as a test molecule to be adsorbed. The BET surface areas of the ACs obtained ranged from 1000 to 1986 m2 g-1. Type I isotherms were obtained for all the samples, although steam and H3PO4 ACs showed a significant mesopore contribution. KOH activation resulted in carbon with a high microporosity (98%) and high iodine adsorption (1030 mg g-1). KOH AC prepared with a KOH/pyrolyzed char weight ratio of 2 and at 900 degrees C showed the highest NH3 adsorption (252 mg g-1), favored by the high microporosity and adequate acidity. Chemical activation (KOH and H3PO4) promotes higher NH3 adsorption than the physical ACs prepared (CO2 and steam). Langmuir and Freundlich adsorption equilibrium models were used to correlate the NH3 adsorption isotherms, obtaining the best fit for the Freundlich equation. The results indicated that olive stone-based activated carbon could be used for commercial AC to remove NH3 from gaseous streams.
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    Comparative Study of Three Dyes' Adsorption onto Activated Carbon from Chenopodium quinoa Willd and Quillaja saponaria
    (2022) Abril, Diana; Ferrer, Victor; Mirabal-Gallardo, Yaneris; Cabrera-Barjas, Gustavo; Segura, Cristina; Marican, Adolfo; Pereira, Alfredo; Duran-Lara, Esteban F.; Valdes, Oscar
    The present study shows porous activated carbon obtained from Chenopodium quinoa Willd and Quillaja saponaria and their use as potential adsorbents to remove three types of dyes from aqueous solutions. The adsorption results were compared with commercial charcoal to check their efficiency. All porous carbon materials were activated using carbon dioxide and steam and fully characterized. Moreover, the steam-activated samples exhibited a high total pore volume with a BET surface area of around 800 m(2) g(-1). Batch adsorption experiments showed that commercial charcoal is the charcoal that offered the best adsorption efficiency for tartrazine and sunset yellow FCF. However, in the case of crystal violet, all activated carbons obtained from Chenopodium quinoa Willd and Quillaja saponaria showed the best captures, outperforming commercial charcoal. Molecular dockings of the dyes on the commercial charcoal surface were performed using AutoDock Vina. The kinetic results of the three isotherm's models for the present data follow the order: Langmuir similar to Freundlich > Temkin.
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    Pretreated Eucalyptus globulus and Pinus radiata Barks: Potential Substrates to Improve Seed Germination for a Sustainable Horticulture
    (2023) Escobar-Avello, Danilo; Ferrer, Victor; Bravo-Arrepol, Gaston; Reyes-Contreras, Pablo; Elissetche, Juan P.; Santos, Jorge; Fuentealba, Cecilia; Cabrera-Barjas, Gustavo
    Commercial forest plantations in Chile are dominated by pine (Pinus radiata) and eucalyptus (Eucalyptus globulus). Tree bark is the main by-product of the forestry industry and has low value, but great potential for use as an agricultural substrate. However, the direct use of bark fibers may cause plant phytotoxicity due to the presence of polyphenolic and other compounds. This study aims to evaluate the physicochemical properties of E. globulus and P. radiata bark after water extraction treatments. The phytotoxicity of the resulting extracted bark alone and that mixed with commercial substrates (coconut fiber, moss, peat, and composted pine) at different ratios (25 to 75 wt%) were assessed using the Munoo-Liisa vitality index (MLVI) test. For all treatments, the seed germination and growth of radish (Raphanus sativus) and Chinese cabbage (Brassica rapa) species were evaluated and compared to a commercial growing medium (peat) as a control. The optimal mixture for seed growth was determined to be 75% extracted E. globulus bark fiber and 25% commercial substrates such as peat (P), coconut fiber (C), moss (M), and composted pine (CP), as indicated by the MLVI and germination results. Two phytostimulant products, chitosan and alginate-encapsulated fulvic acid, were added to the best substrate mixture, with the purpose of improving their performance. Encapsulated fulvic acid at 0.1% w/v was effective in promoting plant growth, while chitosan at all of the concentrations studied was effective only for mixture 75E-25CP. The mixture of E. globulus fiber and commercial substrates, containing a high proportion of water-extracted fiber (75%), shows the potential to be used in the growth of horticultural crops and in the plant nursery industry.
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    Solubility and Thermodynamic Parameters of H2S/CH4 in Ionic Liquids Determined by 1H NMR
    (2024) Zarraga, Jeannette; Zapata, Mariana; Ibarra, Darmenia; Duarte, Darlin; Morillo, Angel; Llovera, Ligia; Gonzalez, Eduardo; Ferrer, Victor; Chirinos, Juan
    Natural gas remains an important global source of energy. Usually, sour gas from the well or refinery stream contains H2S among other contaminants that should be removed to fulfill permissible standards of use. Despite the use of different gas-liquid sour gas upgrading technologies, ionic liquids (ILs) have been recognized as promising materials to remove H2S from sour gas. However, data concerned with thermodynamic solution functions of H2S in ILs have scarcely been reported in the literature. In this work, solution H-1 NMR spectroscopy was employed for quantifying H2S soluble in [BMIM][Cl] and for gaining a better understanding of the H2S-IL interaction. Experiments were carried out in a Young-Tap NMR tube containing a saturated solution of H2S/CH4/[BMIM][Cl] and recording spectra from 298 to 333 K. The thermodynamic solution functions, determined from the Van't Hoff equation, showed that solubility of the H2S in the [BMIM][Cl] is an exothermic gas-liquid physisorption process (Delta H-sol degrees = -66.13 kJmol(-1)) with a negative entropy change (Delta S-sol degrees = -168.19 JK(-1) mol(-1)). H-1 NMR spectra of the H2S/[BMIM][Cl] solution show a feature of strong solute-solvent interactions. However, solubility enthalpy is a fifth of the H-S bond energy value. Results from H-1 NMR spectroscopy also agree with those from the bench dynamic experiments.