Artículos de revista INAMAT2 - INAMAT2 aldizkari artikuluak

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Browsing Artículos de revista INAMAT2 - INAMAT2 aldizkari artikuluak by Author "Afailal, Zainab"

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    PublicationOpen Access
    Bio-oil fractionation according to polarity and molecular size: characterization and application as antioxidants
    (American Chemical Society, 2024-12-21) Fonts, Isabel; Lázaro, Cristina; Cornejo Ibergallartu, Alfonso; Sánchez, José Luis; Afailal, Zainab; Gil-Lalaguna, Noemí; Arauzo, Jesús María; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako Gobernua
    Bio-oil obtained from biomass pyrolysis has great potential for several applications after being upgraded and refined. This study established a method for separating bio-oil into different fractions based on polarity and molecular size to extract phenolic and polyphenolic compounds with antioxidant properties. The fractions were analyzed using various spectroscopic and chromatographic techniques, such as GC/MS, FTIR, UV-vis, SEC, DOSY-NMR, 13C-NMR, and 31P-NMR. The antioxidant properties of these fractions were tested by examining their ability to improve the oxidative stability of biodiesel. The results strongly connected the bio-oil's chemical functionalities and antioxidant power. During solvent fractionation, dichloromethane could extract phenolic structures, which were subsequently size-fractionated. The subfractions with lower molecular weight (in the order of monomers and dimers) outperformed the antioxidant potential of the crude bio-oil. Heavier subfractions from dichloromethane extraction did not show good antioxidant abilities, which was related to the low hydroxy group content. After solvent extraction, phenolic oligomers remained in the water-insoluble/dichloromethane-insoluble fraction, which showed good antioxidant potential despite its low solubility in biodiesel.
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    PublicationOpen Access
    Production of phenolic compounds from argan shell waste by reductive catalytic fractionation
    (Springer, 2023) Afailal, Zainab; Gil-Lalaguna, Noemí; Høj, Martin; Cornejo Ibergallartu, Alfonso; Sánchez, José Luis; Jensen, Anker Degn; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
    For efficient utilization of lignocellulosic biomass components, reductive catalytic fractionation appears as a promising biorefinery strategy. In this work, this concept of biomass valorization was used to study the potential of an unexplored feedstock, argan shells. This material was processed in a non-catalytic route and over a Pd/C catalyst in two different reaction media. The effects of the treatment temperature (250, 275, and 300 °C), as well as the catalyst loading (catalyst/argan shells mass ratio of 0.05 and 0.1 g/g), were also studied. The main product (lignin-derived oil) was thoroughly characterized using GC/MS/FID, SEC, and NMR. The highest monomer yields of 48-49 wt% based on the lignin content were obtained for n-butanol/water reaction medium at 300 °C using a Pd/C catalyst load of 0.1 g/g and for methanol reaction medium at 275 °C and 0.05 g/g. Significantly lower monomeric phenol yields were obtained in the non-catalytic route (4-19 wt% for n-butanol/water and 9-16 wt% for methanol). The main phenolic monomers in the catalytic pathway were 4-n-propanolguaiacol, 4-n-propanolsyringol, and 4-alkyl guaiacols and syringols, with some differences in the selectivities from one solvent to another.