PhD in Biotechnology from the University of Aveiro
RESEARCH, TEACHING, or OTHER INTERESTS
Food Science, Biotechnology, Agricultural and Biological Sciences, Environmental Engineering
17
Scopus Publications
Scopus Publications
Pine bark-derived biosorbents for sustainable dye removal in textile wastewater treatment Pedro Gonçalves, Ariana Pintor, Olivia S.G.P. Soares, Manuel F.R. Pereira, Cidália Botelho, Ricardo M. Ferreira Chemical Engineering Science, 2026 • Dual valorization of pine bark into tannin resin and Fe-modified residue adsorbents. • Response Surface Methodology (RSM) successfully optimized tannin extraction (R 2 = 0.88). • Iron impregnation combined with thermal treatment improved dye removal efficiency. • TT-10Fe biosorbent achieved 99.6% removal of Direct Blue 85 with negligible Fe leaching. • Adsorption capacity reached 16.1 mg/g, with near-complete removal in 2 h. Dyes are extensively used in the textile industry and often discharged as wastewater, posing significant environmental risks if untreated, so developing cost-effective and sustainable treatment methods is crucial. This study evaluates biosorbents derived from pine bark ( Pinus pinaster ), a by-product of Portugal’s timber industry for textile dye removal. Initially, tannin-based adsorbents were produced via magnetic stirring-assisted extraction (MSAE) using distilled water as a solvent, and the effects of solid-to-liquid ratio, temperature, and extraction time were tested over 12 trials, yielding a maximum total soluble solids content of 8.4 % at 1:30, 80 °C, and 60 min. Higher temperatures and solid-to-liquid ratios increased total phenolic content (TPC) while reducing condensed tannin (CT) content, with shorter extractions yielding more of both. The highest TPF and TC levels were 0.9 ± 0.2 mg/g (1:10, 80 °C, 20 min) and 1.13 ± 0.01 mg/g (1:30, 70 °C, 20 min), respectively. The remaining solid residue was dried and used to produce iron-coated adsorbents, prepared by sonicating samples with 5 % and 10 % FeCl 3 for 90 min. Thermally treated adsorbents were obtained after Fe impregnation through pyrolysis at 400 °C for 4 h under hydrogen (3 h) and nitrogen (1 h). Adsorption tests were carried out using a simulated real textile wastewater containing Sirius Blue K-CFN dye (80 mg/L). While the polymerized tannin material showed negligible removal of Direct Blue 85, confirming that it is not effective for this type of anionic dye, increasing the iron content of the pine bark improved adsorption, with the thermally treated pine bark coated with 10 % iron removing 99.60 ± 0.04 % of the dye within 24 h, with minimal iron leaching. Kinetic studies showed a maximum adsorbed amount of 16.1 ± 0.2 mg/g, for an initial dye concentration of 80 mg/L, with nearly complete dye removal achieved in 2 h.
Iron-Coated Pine Bark as Biosorbents for Textile Wastewater Treatment: A Sustainable Approach Pedro Gonçalves, Ariana Pintor, Olivia S. G. P. Soares, Manuel F. R. Pereira, Cidália M. S. Botelho, Ricardo M. Ferreira Water Switzerland, 2025 Dyes are widely used in textile processing and are frequently discharged without adequate treatment, posing risks to aquatic ecosystems through reduced water quality, toxicity to organisms, and long-term environmental degradation. To address the need for sustainable remediation solutions, this study investigated the use of pine bark (Pinus pinaster), an abundant forestry byproduct, as a low-cost biosorbent for textile dye removal. Powdered (<0.5 mm) and granular (>1 mm) bark fractions were washed, dried, and modified through iron impregnation (10 wt.% Fe) via sonication in an FeCl3·6H2O solution, with one iron-coated variant subsequently subjected to thermal treatment at 400 °C under nitrogen (1 h) and hydrogen (3 h). Adsorption performance was evaluated using synthetic effluents containing Sirius Blue, Astrazon Red, and Sirius Yellow, individually and as a ternary mixture (80 mg/L each), with added NaCl and NaHCO3 to simulate realistic conditions. Thermally treated granular iron-coated bark showed the highest removal efficiency, achieving >90% dye elimination within 24 h without detectable iron leaching, along with strong iron retention (~80%) and a 53% thermal-treatment yield. Maximum adsorption reached 15.51 mg/g at 5.0 g/L, while lower adsorbent doses increased capacity (26.8 mg/g) but reduced overall removal (~83%). Kinetic analysis was dose-dependent: the pseudo-first-order model provided the best fit at 5.0 g/L, reflecting the rapid approach to equilibrium, whereas the Elovich model fitted best at 2.5 g/L (R > 0.99), consistent with heterogeneous surface interactions under limited adsorbent availability. These results demonstrate the potential of thermally treated iron-coated pine bark as an efficient and sustainable biosorbent for textile wastewater treatment.
Valorization and characterization of Camellia sp. fruit husks through autohydrolysis: bioactive compounds, cosmetics and bioethanol production F. Díaz, R. Ferreira, K.D. González-Gloria, S. Inoubli, N. Flórez-Fernández, A. Almeida, Rita Silva-Reis, C. Vieira, Rosa M. Rodríguez-Jasso, Héctor A. Ruiz, Susana M. Cardoso, M.D. Torres, B. Piñeiro-Lago, H. Domínguez Bioresource Technology Reports, 2025 Autohydrolysis is a green technology know for its efficiency as to several approaches. However, its mostly done alone or paired with an organic solvent method. This study explored the effects of two autohydrolysis stages of Camellia seed husks at varying temperatures (140–220 °C) and solid-to-liquid ratios (1:8 and 1:30 w / v ). Liquid fractions were rich in phenolics, obtaining the highest value at 140 °C (23.8 ± 0.01 g GAE/100 g DW), which was subjected to an antimicrobial assay against methicillin-resistant Staphylococcus aureus (MRSA); with peak antioxidant capacity at 160 °C (TEAC: 34.0 ± 0.2 g TroloxE/100 g DW; FRAP: 11.8 ± 0.2 g BHTE/100 g DW), both in the first stage. The second-stage increased xylose recovery up to 59.5 %. This fraction was subjected to a probiotic assay using lactic acid bacteria. Selected extracts were also used to develop creams with suitable mechanical characteristics. Fermentability of pretreated solids was carried out. Pre-saccharification released 27.24 ± 1.2 g/L glucose from 200 °C-treated biomass, compared to 9.09 ± 0.3 g/L at 140 °C. Ethanol production reached 18.56 ± 0.79 g/L after 48 h fermentation with the 200 °C sample, while remaining below 3.8 ± 0.6 g/L for the 140 °C-treated material. These findings demonstrate that autohydrolysis not only enables selective recovery of bioactives for health benefits, but is also adequate for bioethanol production, highlighting its biorefinery potential. • Hydrothermal processing of Camellia seed husks was made at 140–220 °C. • Extracts were rich in xylose, arabinose, saponins, and phenolics. • Lactobacillus fermentum and L. plantarum improved growth at 0.5–1 %. • Antimicrobial screening revealed a minimum inhibitory concentration at 1.5–2 mg/mL. • Ethanol production reached 18.56 ± 0.79 g/L after 48 h fermentation.
Nanoencapsulation of vitamin B12 with Opuntia ficus-indica seed oil for food supplements uses Ricardo M. Ferreira, Andreia Granja, Artur M.S. Silva, Jorge A. Saraiva, Salette Reis, Susana M. Cardoso Food and Bioproducts Processing, 2025 This study addressed the nutritional challenges faced by vegetarians and vegans, emphasizing the limited access to essential nutrients like vitamin B12 found mainly in animal-based products. To enhance its bioavailability and reduce dependence on supplements, a lipid-based nanosystem for vitamin B12 encapsulation using vegan-friendly Opuntia ficus-indica seed oils was used. Extracts from these oils, obtained via Magnetic Stirrer Assisted Extraction (MSAE) and n-hexane, exhibited high yields and beneficial properties, including elevated total phenolic content and antioxidant activity. GC-MS analysis revealed significant levels of linoleic, oleic, and palmitic acids, essential for nutritional health. Nanostructured lipid carriers (NLC) produced using ultrasounds and incorporating O. ficus-indica seed oil demonstrated favorable characteristics for oral administration, effective B12 encapsulation, resilience to harsh conditions, and biocompatibility, as confirmed by L929 cell testing. This study highlights the promising potential of lipid-based nanosystems in improving vitamin B12 bioavailability for vegetarians and vegans, offering a practical solution to address nutrient deficiencies efficiently. • n -hexane extraction of Opuntia ficus-indica seed oils has the highest yields. • Opuntia ficus-indica seed oil can be used for vegan-friendly encapsulation. • Improved particle size, zeta potential, and Vitamin B12 bioavailability of NLC. • Biocompatible NLC for safe Vitamin B12 supplement. • High encapsulation efficiency ensures therapeutic B12 concentration.
Opuntia ficus-indica seed pomace extracts with high UV-screening ability in a circular economy approach for body lotions with solar protection Ricardo M. Ferreira, Noélia Flórez-Fernández, Artur S. Silva, Jorge A. Saraiva, F.L. Figueroa, J. Vega, M. Dolores Torres, Susana M. Cardoso, Herminia Domínguez Journal of Industrial and Engineering Chemistry, 2024 Opuntia ficus-indica seed pomace, a by-product of seed oil extraction, was investigated due to its richness of phytochemical compounds and high antioxidant capacity. The pomace was subjected to hydrothermal extraction using water under subcritical conditions to solubilize various compounds. Different final heating temperatures 120 to 220 °C were applied, and the resulting filtered extracts were analyzed using HPLC and HPSEC to determine the monosaccharide profile and molecular weight of the oligomers. Notably, extractions performed at temperatures between 120-180 °C yielded extracts characterized by elevated levels of glucuronic acid and exhibited higher molecular weights. In contrast, extractions conducted at 200 and 220 °C were distinguished by their enriched xylose content and relatively low molecular weights, falling below 23.6 kDa. The extracts were tested for total phenolic compounds, as well as antioxidant activity using spectrophotometric methods such as TEAC, DPPH, and FRAP. Results showed that increasing temperature led to a corresponding increase in phenolic compounds (from 7.7 to 13.7 gGAE/100 g) and antioxidant activity, with the maximum observed at 200 °C. These phenolic compounds enriched extract were used to produce a body lotion with sun protection factor of 8, with rheological behavior similar to that of commercially available products but without the need for additional UV filters and antioxidants. The lotion was shown to be safe for topical use and did not cause skin irritation. This study highlights the potential of Opuntia ficus-indica seed pomace as a valuable source of phytochemical compounds and demonstrates the feasibility of using hydrothermal extraction to produce eco-friendly commercially interesting compounds.
Infusion from Opuntia ficus-indica Peels: The Effects of Drying and Steeping Conditions Ricardo M. Ferreira, Dulcineia F. Wessel, Artur M. S. Silva, Jorge A. Saraiva, Susana M. Cardoso Beverages, 2023 The escalating production of processed prickly pear products has led to a substantial rise in waste materials, particularly peel, which is rich in bioactive chemicals and holds the potential for value-added product development. However, the high perishability of these peels imposes effective preservation techniques. So, this work aimed to explore the potential of prickly pear peels from O. ficus-indica ‘Rossa’, ‘Gialla’, and ‘Bianca’ cultivars for the production of Opuntia beverages, namely infusions. To achieve this goal, two distinct drying methods, namely microwave drying and a food dehydrator, were employed with the latter method, resulting in the higher recovery of phenolic compounds (0.5 mgGAE/mL vs. 0.16 mgGAE/mL) and the higher antioxidant capacity of the resulting infusions. Additionally, various steeping conditions involving water temperatures of 80, 90, and 100 °C were assessed to maximize the levels of phenolic compounds and antioxidant activity. The results demonstrate that the better overall drying method temperature and steeping conditions for the food dehydrator were at 35 °C and boiling water (100 °C) due to its generally better results and practicality. Sensorial trials revealed that the three infusions were generally accepted (score > 7.20 out of 9) but that O. ficus-indica ‘Rossa’ received the highest ratings. This study offers valuable insights for optimizing drying methods and steeping conditions to preserve and enhance the bioactive compounds and antioxidant potential in prickly pear peel infusions, promoting their sustainable utilization as functional ingredients in food and nutraceutical applications.
