Polymers and Plastics, Organic Chemistry, Catalysis, Environmental Chemistry
29
Scopus Publications
Scopus Publications
Development of Biocatalysts Based on Candida Antarctica B Lipase Immobilized Onto Crosslinked Porous Polymers Containing Varied Monomeric Compositions Ezaine C. C. Torquato, Michelle M. Santos, Eliane P. Cipolatti, Evelin A. Manoel, Gisele C. V. Iulianelli, et al. Journal of Applied Polymer Science, 2025 Crosslinked polymer particles can be used successfully as support for enzyme immobilization. For this reason, the relationship between the particle morphology and immobilization parameters is investigated in the present manuscript. Particularly, this study focuses on the preparation of biocatalysts using lipase from Candida antarctica B (Cal‐B) and crosslinked polymers made from divinylbenzene (DVB) and ethylene glycol dimethacrylate (EGDMA). Several monomers were utilized in this process, including methyl methacrylate (MMA), styrene (Sty), glycidyl methacrylate (GMA), methacrylic acid (MA), vinylbenzyl chloride (VBC), and 2‐vinylpyridine (Vpy). Many of these monomers were used to synthesize biocatalysts for the first time. The highest immobilization yields were achieved using Sty‐DVB, MA‐DVB, and DVB supports, which presented high surface areas and pore diameters. Among the developed biocatalysts, CalB‐MMA‐DVB, which presented a specific area of 320.9 m2/g, presented the highest esterification activity of 1410 ± 176 U/g bio−1. In contrast, biocatalysts manufactured with polymer particles with smaller specific areas but containing polar monomers, such as Cal‐B‐MA‐EDGMA, Cal‐B‐GMA‐EDGMA, Cal‐B‐Vpy‐DVB, and Cal‐B‐VBC‐EDGMA, presented higher hydrolytic activities (HA). Cal‐B‐VBC‐EDGMA achieved a catalytic constant (Kcat) of 73.48 × 102 s−1.
Comparative Study of the Addition of TiO2 and TiO2/OMMT Clay on the Properties of PBAT for Biodegradable Food Packaging Applications Antônio de Assis Pereira Teles da Silva, Regina Felipe do Ó, Luciana da Cunha Costa, Fernanda Abbate dos Santos, Gisele Cristina Valle Iulianelli Materials Research, 2025 Microplastics from synthetic polymers significantly impact ecosystems and human health, making biodegradable polymers a promising alternative. To enhance their properties, nanofillers have been widely explored. In this study, TiO2 nanoparticles, alone and combined with B8 OMMT clay, were incorporated into a PBAT matrix to improve its functionality for food packaging applications. Results revealed that nanofillers did not significantly alter PBAT’s crystallinity (Xc ≈ 33%) or thermal stability (Tonset ≈ 375 °C), and the nanocomposites exhibited a predominantly intercalated morphology. Furthermore, low concentrations of nanofillers improved matrix uniformity. Contact angle measurements showed increased hydrophilicity in all formulations, with B8 OMMT systems exhibiting the highest hydrophilicity. The mechanical performance of the PBAT/B8/TiO2 systems was more promising in terms of stiffness, with a 44% increase in Young’s modulus for the PBAT/B8/TiO2 0.5% system. However, all PBAT/B8/TiO2 systems exhibited a more pronounced loss of ductility. Water activity (aW) analysis demonstrated that TiO2 alone reduced aW values to 0.50–0.53, which could potentially enhance biosafety, while the addition of B8 OMMT increased aW to 0.69–0.76, potentially increasing susceptibility to microbial growth. Notably, systems with TiO2 alone showed the greatest potential for food packaging applications due to their increased biosafety, thermal stability, and favorable set of properties.
Evaluation of Crosslinked Sulfonated Polymers Derived from Different Resins for Removal of Ammonium Ions Marcos Guidi Torquato, Ezaine Cristina Corrêa Torquato, Ana Carolina Lopes Moraes, Fernanda de Andrade Buás Campeão, Rodrigo José França, et al. Macromolecular Symposia, 2022 Ammoniacal nitrogen is an environmental pollutant present in various effluents, such as landfill leachate. It is possible to use ion‐exchange resins in systems for tertiary treatment of effluents containing NH4+ ions and as support for NH3 recovery after treatment of these effluents by employing air stripping. This article presents an exploratory study of sorption of NH4+ ions by sulfonic resins prepared from styrene‐divinylbenzene (Sty‐DVB) copolymers with varied morphological structures: hypercrosslinked resin, a macroporous copolymer prepared by conventional aqueous suspension polymerization, and a polyHIPE copolymer. These three resins are sulfonated by employing concentrated sulfuric acid. The sulfonic resin derived from hypercrosslinked resin has the highest cation exchange capacity (5.06 meq g−1) and is selected for batch studies and column tests. The best result (removal rate of 87%) is achieved with 20 g of resin, time of 20 min, and concentration of 100 ppm. Kinetic behavior and sorption processes are best described by the pseudo‐second‐order, Weber–Morris intraparticle diffusion, and Langmuir models. The saturation point occurs when 900 mL of the NH4+ solution at 2500 ppm (15 mL min−1) is percolated through the column. The working capacity of this resin is 14.06 g cm−3. The resin can be reused during five cycles with removal efficiency between 71% and 82%.