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National Laboratory of Energy and Geology Scientific Repository
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Biopolymers Derived from Forest Biomass for the Sustainable Textile Industry
Publication . Dias, J. C.; Marques, Susana; Branco, Pedro C.; Rodrigues, Thomas; Torres, Cristiana A.V.; Freitas, Filomena; Evtuguin, Dmitry; Silva, Carla
ABSTRACT: In line with environmental awareness movements and social concerns, the textile industry is prioritizing sustainability in its strategic planning, product decisions, and brand initiatives. The use of non-biodegradable materials, obtained from non-renewable sources, contributes heavily to environmental pollution throughout the textile production chain. As sustainable alternatives, considerable efforts are being made to incorporate biodegradable biopolymers derived from residual biomass, with reasonable production costs, to replace or reduce the use of synthetic petrochemical-based polymers. However, the commercial deployment of these biopolymers is dependent on high biomass availability and a cost-effective supply. Residual forest biomass, with lignocellulosic composition and seasonably available at low cost, constitutes an attractive renewable resource that might be used as raw material. Thus, this review aims at carrying out a comprehensive analysis of the existing literature on the use of residual forest biomass as a source of new biomaterials for the textile industry, identifying current gaps or problems. Three specific biopolymers are considered: lignin that is recovered from forest biomass, and the bacterial biopolymers poly(hydroxyalkanoates) (PHAs) and bacterial cellulose (BC), which can be produced from sugar-rich hydrolysates derived from the polysaccharide fractions of forest biomass. Lignin, PHA, and BC can find use in textile applications, for example, to develop fibers or technical textiles, thus replacing the currently used synthetic materials. This approach will considerably contribute to improving the sustainability of the textile industry by reducing the amount of non-biodegradable materials upon disposal of textiles, reducing their environmental impact. Moreover, the integration of residual forest biomass as renewable raw material to produce advanced biomaterials for the textile industry is consistent with the principles of the circular economy and the bioeconomy and offers potential for the development of innovative materials for this industry.
Optimizing bacterial nanocellulose production from eucalyptus bark: A circular approach to wastewater management and resource recovery
Publication . Rodrigues, Ana Cristina; Martins, Daniela; Duarte, Maria Salomé; Marques, Susana; Gama, Miguel; Dourado, Fernando; Carvalho, Ricardo; Cavaleiro, Ana
ABSTRACT: The production cost of bacterial nanocellulose (BNC) is a major limitation to its widespread use. However, this limitation can be addressed by using alternative low-cost substrates and high-yield strains. Agro-industrial wastederived substrates offer a cost-effective and sustainable solution, but their high organic load often requires additional downstream wastewater treatments. Here, we optimized static BNC production using eucalyptus bark hydrolysate (EBH) as a low-cost carbon source and proposed a circular approach for wastewater management. Optimization was performed using response surface methodology - central composite design. The optimized EBH medium yielded a 39.7-fold increase compared to standard medium, with a maximum BNC production of 8.29 f 0.21 g/L. Fermentation wastewater only (WaF) and combined with BNC washing streams (WaW) revealed high levels of organic matter, namely chemical oxygen demand (COD) of 159.0 f 2.0 and 41.1 f 0.3 g/L, and volatile solids (VS) of 99.5 f 0.9 and 26.3 f 0.2 g/L, respectively, requiring treatment before disposal. A sequential anaerobic-aerobic digestion was investigated for wastewater treatment and valorisation. Anaerobic digestion proved to be effective in treating the wastewater: methanization percentages over 87 % were achieved, and methane productions of 486 f 2 and 544 f 30 L/kg VS were obtained from WaF and WaW, respectively. Subsequent aerobic treatment was unsuccessful in further reducing COD levels (approximately 1.5 g/L). Notably, treated wastewater was recycled into the production process up to 45 % without affecting the BNC yield. This study provides valuable insights into the optimization of BNC production from lignocellulosic biomass and the management of wastewater streams, contributing to the development of a more sustainable and economically viable process.
Exploring Marine Biomineralization on the Al-Mg Alloy as a Natural Process for In Situ LDH Growth to Improve Corrosion Resistance
Publication . Marques, Maria João; Mercier, Dimitri; Seyeux, Antoine; Zanna, Sandrine; Tenailleau, Christophe; Duployer, Benjamin; Jeannin, Marc; Marcus, Philippe; Basséguy; BASSEGUY, Regine
ABSTRACT: This study provides a detailed characterization of the AA5083 aluminum alloy, surface, and interface over 6 months of immersion in seawater, employing techniques such as SEM/EDX, GIXRD, mu-Raman and XPS. The purpose was to evaluate the evolution of the biomineralization process that occurs on the Al-Mg alloy. By investigating the specific conditions that favor the in situ growth of layered double hydroxide (LDH) during seawater immersion as a result of biomineralization, this research provides insights into marine biomineralization, highlighting its potential as an innovative and sustainable strategy for corrosion protection.
Evolution of atomically dispersed co-catalysts during solar or UV photocatalysis for efficient and sustained H2 production
Publication . Capelo, Anabela; Fattoruso, Domenico; Valencia-Valero, Laura; Esteves, M. Alexandra; Rangel, Carmen M.; Puga, Alberto
ABSTRACT: The evolution of metal/titania photocatalysts during photocatalytic H-2 evolution is herein studied. Samples containing atomically dispersed Pt co-catalysts (single atoms, clusters and sub-nanoparticles) formed after calcination were compared to pre-reduced analogues mostly having metallic nanoparticles (diameters >1 nm) during ethanol photoreforming under either UV-rich irradiation or natural sunlight. Aggregation of ultra-dispersed oxidised platinum entities (Pt delta+) with concomitant reduction into Pt-0 nanoparticles (1-2 nm) was observed after UV irradiation by transmission electron microscopy (TEM), and diffuse reflectance UV-visible (DRUV-vis) and X-ray photoelectron (XPS) spectroscopies. A parallel, albeit slower, evolution trend was evidenced during solar photocatalysis. Conversely, atomically dispersed Cu co-catalyst species did not grow and became in-situ reduced into sub-nanometric Cu-0 under irradiation. Hydrogen production rates were remarkably high during initial stages of UV irradiation, and then declined to a sustained regime (approximate to 50 and 8 mmol g(-1) h(-1) for Pt/TiO2 or Cu/TiO2, respectively, for up to 24 h of irradiation). Steadier solar photoreforming was observed in experiments performed in a compound parabolic collector tubular reactor (approximate to 7.6 and 1.7 mmol g(-1) h(-1) for Pt/TiO2 or Cu/TiO2, respectively). Despite the non-negligible effect of co-catalyst rearrangement on activity rationalised herein, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy measurements pre- and post-photocatalysis suggest that accumulation of strongly adsorbed degradation intermediates, chiefly acetate, is a major cause for rate decreases. Notwithstanding, this phenomenon did not result in total deactivation, so that sustained hydrogen production upon long-term irradiation was not compromised.
Hybrid Variable Renewable Power Plants: A Case Study of ROR Hydro Arbitrage
Publication . Catarino, Isabel; Romão, Inês; Estanqueiro, Ana
ABSTRACT: Wind and solar energy sources, while sustainable, are inherently variable in their power generation, posing challenges to grid stability due to their non-dispatchable nature. To address this issue, this study explores the synergistic optimization of wind and solar photovoltaic resources to mitigate power output variability, reducing the strain on local grids and lessening the reliance on balancing power in high-penetration renewable energy systems. This critical role of providing stability can be effectively fulfilled by run-of-river hydropower plants, which can complement fluctuations without compromising their standard operational capabilities. In this research, we employ a straightforward energy balance model to analyze the feasibility of a 100 MW virtual hybrid power plant, focusing on the northern region of Portugal as a case study. Leveraging actual consumption and conceptual production data, our investigation identifies a specific run-of-river plant that aligns with the proposed strategy, demonstrating the practical applicability of this approach.