Loading...
4 results
Search Results
Now showing 1 - 4 of 4
- Thermogravimetric analysis of high-density cork granules using isoconversional methodsPublication . Ribeiro, A.M.; Ramalho, Elisa; Pimenta, Maria Paula; Pilão, Rosa MariaIn the present work thermogravimetric techniques were used to study the thermal degradation of high-density cork granules. Pyrolysis experiments were carried out for four heating ramps (10, 15, 20 and 25 °C.min−1), using nitrogen as the carrier gas. From the differential thermogravimetric (DTG) curves it was seen that degradation mainly occurs from 220 °C to 525 °C for the main components of cork (suberin, lignin, cellulose, and hemicellulose). It was also observed that for temperatures higher than 525 °C and up to 900 °C, lignin continued to decompose. Activation energies were calculated using the data obtained and the two isoconversional methods Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO). For the KAS method, and for degrees of conversion between 0.10 and 0.85, the activation energies varied between 232.2 and 353.0 kJ.mol−1. Using the FWO method and for the same degrees of conversion, the activation energies were in the range of 230.0 to 346.6 kJ.mol−1. These values agree with data provided by other authors, for different lignocellulosic biomass.
- Wet-white shavings as a potential source for leather retanning bioagentsPublication . Freitas, Teresa; Marujo, I.; Ribeiro, D.; Crispim, Alfredo; Neto, Maria Paula; Gaião, J.; Oliveira, J.The tanning industry generates a high quantity of solid wastes, so there is a need to create ways to value these wastes with aim to reduce environmental impact. A lot of research work has been done recently and some authors have shown the potential for obtaining protein hydrolysates from solid wastes and its application. The present work had a main objective the wet-white shavings valorization by production of hydrolysed protein and biopolymrs for leather retanning.
- Leather wastes as a potential source of biochemicals and biomaterialsPublication . Dias, R.; Crispim, A.; Silva, P.; Neto, P.; Gaião, J.; Oliveira, J.Framework: Leather industry is one of the oldest and most traditional industries, although it produces high amount of solid waste and wastewater; • Only 20% of the of the hide results in finished leather products • Annually, 41,000 tons of organic solid waste are generated in Portugal; • From an economical and environmental point of view, there is a great interest in the valorisation of the generated solid wastes.
- Pirólise de agulhas de pinheiro: resultados preliminaresPublication . Nascimento, M.; Silva, F.; Pilão, R.; Neto, M.P.; Ribeiro, A.M.(Introdução) As florestas em Portugal ocupam uma área aproximada de 3 224 200 ha, apresentando como espécies predominantes o sobreiro, o pinheiro e o eucalipto (ICNF, 2021). Os pinheiros ocupam cerca de 28 % desta área e geram diversos resíduos, entre os quais as agulhas, que se não forem retiradas das florestas podem agravar o problema dos incêndios florestais (Omvesh et al., 2023). A energia proveniente de resíduos florestais pode ser transformada em combustíveis ou em outros produtos químicos através de processos termoquímicos, como a pirólise, onde há a formação de três fases distintas: o carbonizado, o bio-óleo e o gás (Basu, 2018).