Faculdade de Ciências e Tecnologia
URI permanente desta comunidade:
Notícias
a definir... (FCT)
http://www.fct.ualg.pt/
Navegar
Percorrer Faculdade de Ciências e Tecnologia por Objetivos de Desenvolvimento Sustentável (ODS) "13:Ação Climática"
A mostrar 1 - 2 de 2
Resultados por página
Opções de ordenação
- Customising sustainable bio-based polyelectrolytes: introduction of charged and hydrophobic groups in cellulosePublication . Magalhães, Solange; Aliaño González, María José; Cruz, Pedro F.; Rosenberg, Rose; Haffke, Dirk; Norgren, Magnus; Alves, Luís; Medronho, Bruno; Rasteiro, Maria da GraçaAbstract: Cellulose has been widely explored as a sustainable alternative to synthetic polymers in industrial applications, thanks to its advantageous properties. The introduction of chemical modifications on cellulose structure, focusing on cationic and hydrophobic modifications, can enhance its functionality and expand the range of applications. In the present work, cationization was carried out through a two-step process involving sodium periodate oxidation followed by a reaction with the Girard T reagent, yielding a degree of substitution for cationic groups (DScationic) between 0.3 and 1.8. Hydrophobic modification was achieved via esterification with fatty acids derived from commercial plant oils, using an enzyme-assisted, environmentally friendly method. Lipase-catalysed hydrolysis, optimised at 0.25% enzyme concentration and with a 1 h reaction time, produced an 84% yield of fatty acids, confirmed by FTIR and NMR analyses. The degree of substitution for hydrophobic groups (DShydrophobic) ranged from 0.09 to 0.66. The molecular weight (MW) of the modified cellulose derivatives varied from 1.8 to 141 kDa. This dual modification strategy enables the creation of cellulose-based polymers with controlled electrostatic and hydrophobic characteristics, customisable for specific industrial applications. Our approach presents a sustainable and flexible solution for developing cellulose derivatives tailored to diverse industrial needs.
- A spatial framework for assessing irrigation water use in overexploited mediterranean aquifersPublication . López-Pérez, Esther; Manzano-Juarez, Juan; Jiménez-Bello, Miguel Angel; García-Prats, Alberto; Sanchis-Ibor, Carles; Rubio-Martín, Adrià; Boubekri, Fatima Zahrae; Kajji, Abdellah; TUFONI, PAOLO; Nunes, Luís; Pulido-Velazquez, ManuelIrrigated agriculture in Mediterranean semi-arid regions is increasingly constrained by aquifer depletion and climate change. Enhancing water use efficiency in the irrigation of perennial crops is essential for long-term agricultural sustainability. This study introduces a Spatial Irrigation Adequacy Index (SIAI), a normalized index expressing the deviation between actual evapotranspiration (ETa) and Crop Water Requirements (CWR). The framework was applied to assess irrigation performance in grapevine (Vitis vinifera), apple orchards (Malus domestica) and citrus tress (Citrus sinensis) across three groundwater-dependent systems: Requena-Utiel (Spain), Ain Timguenai (Morocco), and Campina de Faro (Portugal). ETa was estimated using Landsat 8 and 9 imageries processed with the SSEBop model, while crop water demand was calculated with the FAO-56 dual crop coefficient method incorporating site-specific agroclimatic data. Results revealed distinct crop-specific irrigation patterns: grapevines achieved near-optimal water use, apple orchards were generally over-irrigated, and citrus groves experienced persistent deficits. The framework enables scalable, transferable assessments of irrigation performance, supporting sustainable water management and adaptive irrigation under climate variability, with potential applications in digital farm management systems, water authority decision-making, and corporate ESG reporting frameworks.