9 documents found, page 1 of 1
Natural deep eutectic solvents - NADES: green solvents for extraction and enzym...
Freitas, David SilvaNesta tese de doutoramento foram desenvolvidos, caracterizados e aplicados novos solventes eutécticos naturais profundos (NADES) para processos de síntese enzimática, extração, e preparação de emulsões translúcidas de NADES-em-óleo (TEs). Pela primeira vez, os NADES foram utilizados simultaneamente como substratos e solventes em reações de esterificação catalisadas pela lipase de Aspergillus oryzae em meio anid...
Enhancing insights into the phenomena of deep eutectic solvents
Freitas, David Silva; Cavaco-Paulo, Artur; Silva, C.Environmental concerns have spurred a quest for more sustainable and safer solvents, aiming to replace aggressive and harmful chemical products in industrial processes. In response to this need, deep eutectic solvents (DES) have emerged as a progressive evolution from ionic liquids. These innovative solvents result from the synergistic combination of two or more chemical compounds, exhibiting a significant redu...
Development and optimization of a SPME-GC-FID method for ethanol detection
Costa, Nuna G.; Freitas, David Silva; Barros, Aline Magalhães; Silva, Carla; Antunes, Joana C.; Rocha, Ana M.A solid-phase microextraction (SPME) injection gas chromatography was validated with the flame ionization detection method (GC-FID) using a capillary column to detect ethanol. The method was used to determine ethanol in fluids with biomedical, clinical, and forensic importance, including water, phosphate-buffered saline (PBS), and artificial sweat. The strategy produced good peak resolution and showed a linear ...
Physicochemical properties of new silicone alternatives unraveled by experiment...
Ferreira, Tiago; Rocha, Diana; Freitas, David Silva; Noro, Jennifer Martins; Castro, Mariana de; Roque, Catarina; Guimarães, Diana Isabel PereiraThe cosmetic industry has recognized an increasing demand for environmentally sustainable solutions due to the classification of certain commonly used components as bioaccumulative and hazardous. The European Union has implemented restrictions on the utilization of some components, including silicones, which limit their concentration. The present investigation intends to find new solutions for cosmetic formulat...
Thermo-mechanical performance of nanostructured electrospun composites produced...
Teixeira, Marta Albertina; Fertuzinhos, Aureliano Costa; Freitas, David Silva; Silva, C.; Ferreira, Diana P.; Felgueiras, Helena PradoThe purpose of this research was to analyze the morphology, thermal and mechanical properties of poly(vinyl alcohol) (PVA)-based electrospun mats reinforced with cellulose acetate (CA) or cellulose nanocrystalline (CNC) for potential applications in wound dressings. Bead-free and water-stable electrospun nanofibers made of blends of PVA and CA or CNC were successfully produced and crosslinked with glutaraldehyd...
Eutectic mixtures as green solvents for laccase-catalyzed reactions
Freitas, David Silva; Rocha, Diana; Noro, Jennifer Martins; Castro, Tarsila Gabriel; Cavaco-Paulo, Artur; Silva, CarlaLaccases are powerful biocatalysts in the biotechnological field; however, the substrates’ limited solubility in the reaction media may hinder the oxidation process. Herein, different natural deep eutectic solvents (NADES) were investigated as solvents for the laccase-assisted polymerization of catechol and phenolics from coffee. Citric acid, oxalic acid, DL-lactic acid, glucose, glycerol, ethylene glycol, and ...
Laccase-catalyzed synthesis of added-value polymers from cork and grape extracts
Li, Nannan; Freitas, David Silva; Santos, Joana; Venâncio, Armando; Noro, Jennifer Martins; Su, Jing; Wang, Hongbo; Silva, Carla; Cavaco-Paulo, ArturThe development of products from natural plant sources, including agriculture and food wastes, contributes significantly to the circular economy and global sustainability. Cork and grape wastes were employed as the primary sources in this study to obtain compounds of interest under mild extraction conditions. Laccase was applied to oxidize the cork and grape extracts, with the aim of producing value-added molec...
Chitosan nano/microformulations for antimicrobial protection of leather with a ...
Freitas, David Silva; Teixeira, Maria Pilar Araújo; Pinheiro, Inês Braga; Castanheira, Elisabete M. S.; Coutinho, Paulo J. G.; Alves, Maria J.Tanned leather can be attacked by microorganisms. To ensure resistance to bacteria on leather surfaces, protection solutions need to be developed, addressing both environmental issues and economic viability. In this work, chitosan nano/microparticles (CNP) and chitosan/silver nano/microstructures (CSNP), containing silver nanoparticles around 17 nm size, were incorporated into leather, obtained from the industr...
Eutectic compositions, methods and uses thereof
Cavaco-Paulo, Artur; Silva, C.; Freitas, David Silva; Noro, Jennifer MartinsThe present disclosure relates to the development of Natural Deep Eutectic Solvents (NADES) using natural products, like sugars, organic bases and organic acids, as starting compounds. These solvents can be used for the extraction of bioactive compounds from natural sources, such as cork; agricultural wastes, including grape seed and peels; tomato; olive oil; and plants (teas, eucalyptus, lavender, or others), ...