Catarina Viegas Sousa
@metrics.com.pt
Laboratório Associado TERRA
Mechanical Engineering and Resource Sustainability Center
EDUCATION
PhD in Bioenergy (Oct 2017 to Nov 2021)
Master in Energy and Bioenergy (September 2012 to October 2014)
Degree in Agricultural Engineering, Specialization in Plant Protection (September 2000 to December 2006)
RESEARCH, TEACHING, or OTHER INTERESTS
Renewable Energy, Sustainability and the Environment, Environmental Science, Environmental Engineering, Waste Management and Disposal
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Umut Şen, Catarina Viegas, Maria Paula Duarte, Elisabete Muchagato Maurício, Catarina Nobre, Ricardo Correia, Helena Pereira, and Margarida Gonçalves
MDPI AG
Waste-grade cork samples of Quercus cerris were subjected to maceration extraction using 7 different solvents, including pure water (I), pure acetone (II), 75% aqueous ethanol (III), 75% aqueous methanol (IV), 75% aqueous acetone (V), 50% aqueous acetone (VI), and 25% aqueous acetone (VII). The extract yields, extract compositions, as well as antioxidant and antimicrobial activities of the extracts were analyzed. The results showed that maceration extraction was highly efficient, particularly with binary solvents resulting in up to 6% extract yield and up to 488 mg GAE/g extract total phenolic content. The extracts exhibited a variable antioxidant activity determined by DPPH and FRAP methods as well as antimicrobial activity against gram-positive bacteria and fungus determined by agar diffusion test. The CIELAB color parameters of extracts were correlated with maceration time, and the correlation was highest with pure water extracts. The FT-IR spectra of acetone-extracted cork revealed six key markers of phenolic compounds with the presence of peaks at approximately 2920 cm−1, 2850 cm−1, 1609 cm−1, 1517 cm−1, 1277 cm−1, and 1114 cm−1. The overall results suggest that the maceration of waste cork in binary solvents and pure acetone are green alternatives to conventional Soxhlet extraction for the production of polar extracts.
Catarina Viegas and Margarida Gonçalves
Elsevier
Catarina Viegas, Catarina Nobre, Ricardo Correia, Luísa Gouveia, and Margarida Gonçalves
MDPI AG
Co-torrefaction of microalgae and lignocellulosic biomass was evaluated as a method to process microalgae sludge produced from various effluents and to obtain biochars with suitable properties for energy or material valorization. The influence of four independent variables on biochar yield and properties was evaluated by a set of experiments defined by response surface methodology (RSM). The biochars were characterized for proximate and ultimate composition, HHV, and methylene blue adsorption capacity. HHV of the biochars was positively correlated with carbonization temperature, residence time, and lignocellulosic biomass content in the feed. Co-torrefaction conditions that led to a higher yield of biochar (76.5%) with good calorific value (17.4 MJ Kg−1) were 250 °C, 60 min of residence time, 5% feed moisture, and 50% lignocellulosic biomass. The energy efficiency of the process was higher for lower temperatures (92.6%) but decreased abruptly with the increase of the moisture content of the feed mixture (16.9 to 57.3% for 70% moisture). Biochars produced using algal biomass grown in contaminated effluents presented high ash content and low calorific value. Dye removal efficiency by the produced biochars was tested, reaching 95% methylene blue adsorption capacity for the biochars produced with the least severe torrefaction conditions.
Catarina Viegas, Luísa Gouveia, and Margarida Gonçalves
Elsevier BV
Catarina Viegas, Luísa Gouveia, and Margarida Gonçalves
Elsevier BV
Catarina Viegas, Catarina Nobre, André Mota, Cândida Vilarinho, Luísa Gouveia, and Margarida Gonçalves
Elsevier BV
Catarina Viegas, Luísa Gouveia, and Margarida Gonçalves
Elsevier BV
Catarina Viegas, Margarida Gonçalves, Liliana Soares, and Benilde Mendes
Springer International Publishing