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- Influence of Wood Chemical Composition on Liquefaction Efficiency and Polyurethane Foam Properties: A Study of Red Angico and MahoganyPublication . Emilly Silva; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula; Domingos, idalina; Fabricio Gonçalves; Bruna da Silva Cruz; Michelângelo Fassarella; Antônio Thiago de Almeida; Esteves, BrunoBiomass liquefaction is a thermochemical process that converts lignocellulosic materials into reactive liquid intermediates, enabling the production of bio-based polyols as a sustainable alternative to petroleum-derived chemicals. This study investigates the liquefaction of two lignocellulosic biomasses, Red Angico (Anadenanthera colubrina) and Mahogany (Swietenia macrophylla), using a glycerol–ethylene glycol polyalcohol system, chosen for its renewable origin and high solvating efficiency. The resulting polyols were used to produce polyurethane (PU) foams, and their properties were evaluated in relation to biomass composition. The chemical composition of each biomass significantly influenced its liquefaction behavior and polyol characteristics. Mahogany achieved higher liquefaction efficiency, whereas Red Angico polyols generated PU foams with superior mechanical performance, highlighting the influence of species-specific chemistry. Water content and isocyanate index were found to modulate foam structure and compressive strength. This work demonstrates how tailored liquefaction strategies using polyalcohol systems can optimize bio-based PU foam properties, providing a sustainable route for high-performance polymer materials.
- From Invasion to Valorization: Adsorbent Applications of Acacia dealbata Biomass in PortugalPublication . Weber Macena, Morgana; Esteves, Bruno; Jackelline S. Pinto; Rui Novais; Ana P. F. Caetano; Lucas Grosche; Helena Pereira; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa PaulaAcacia dealbata, an invasive species in Portugal, produces large amounts of residual biomass during control operations, thereby presenting challenges and opportunities for sustainable valorization. Heavy metal contamination, including zinc (Zn), remains a critical environmental challenge due to its widespread industrial release and potential ecotoxicological impacts. This study explores the potential use of A. dealbata biomass as a biosorbent for zinc removal from aqueous solutions, comparing the performance of natural biomass and A. dealbata charcoal fines. Adsorption isotherms, kinetics, and surface characterizations were conducted to evaluate their physicochemical properties and sorption efficiency. The A. dealbata charcoal fines exhibited a significantly higher specific surface area (33 m2 g −1 ) and total pore volume (0.030 cm3 g −1 ) compared with the untreated biomass (1.4 m2 g −1 and 0.004 cm3 g −1 , respectively). Despite these structural differences, both materials demonstrated similar maximum adsorption capacities (23.36 and 23.79 mg g−1 for natural and charcoal fines, respectively). These results indicate that untreated A. dealbata biomass can perform as a biosorbent comparably to its carbonized form, representing a simple, low-cost, and sustainable alternative for heavy metal removal, offering a low-energy and sustainable alternative for Zn remediation.
- Liquefaction of Ruscus aculeatus Branches into Bio-Polyols: Process Optimization and Polyol CharacterizationPublication . Yuliya Dulyanska; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula; Fábio Bernardo; Dmitry V. Evtuguin; de Pinho Ferreira Guiné, Raquel; Gonçalves, Fernando Jorge; Luís A. E. Batista de Carvalho; Maria João Barroca; Esteves, BrunoThe conversion of lignocellulosic biomass into bio-polyols through liquefaction has attracted increasing interest as a sustainable route for polymer feedstock production. The liquefaction of Ruscus aculeatus L. branches was investigated to identify optimal processing conditions and to evaluate the properties of the resulting bio-polyols. The effects of temperature, reaction time, particle size, and material-to-solvent ratio on liquefaction yield were systematically studied. Liquefaction yield increased markedly with temperature, reaching up to 92% at 180 °C after 60 min of reaction, while reaction time showed only a marginal effect beyond 15 min. Smaller particle sizes and higher solvent ratios improved liquefaction efficiency, with optimal conditions identified between 1:7 and 1:10 material-to-solvent ratios. The hydroxyl number decreases with increasing liquefaction temperature due to dehydration and condensation reactions. Thermal and rheological analyses indicated improved thermal stability and increased viscosity at higher liquefaction temperatures. These results highlight the potential of Ruscus aculeatus branches as a promising renewable feedstock for bio-polyol production and polyurethane applications.
- DETERMINANTSOF E-WALLETS CONTINUED USAGE INTENTIONPublication . Fragata, Anabela; Pinto, Diana; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula; Oliveira, Carla; Cunha, Madalena; Abrantes, José Luís; Magalhães, Cátia; Correia, Paula; Lousado, José Paulo; Almeida, Ricardo; Mota, MauroRESUMO Introdução: As carteiras eletrónicas agilizam as transações para os consumidores, consolidando cartões de crédito, dinheiro e várias plataformas de pagamento num único dispositivo conveniente, pelo que estas transações de pagamento sem contacto registaram um aumento notável em Portugal nos últimos anos. Objectivo: O objectivo deste artigo é examinar empiricamente os determinantes que influenciam a intenção de uso continuado de um consumidor que utilize carteiras digitais em Portugal. Métodos: Os dados foram analisados através de análises exploratórias e confirmatórias e foi obtido um Modelo de Equações Estruturais, depois de obtidas respostas de 185 inquiridos portugueses. Resultados: Os dados revelaram que a expectativa de desempenho, a expectativa de esforço, as condições facilitadoras e a confiança percebida são determinantes importantes da intenção comportamental das carteiras digitais e terão um impacto positivo na intenção de uso continuado das mesmas. A reputação percebida e a segurança percebida também são determinantes da confiança percebida. Conclusão: A melhoria contínua nestas áreas é imperativa, para melhorar o desempenho da carteira digital e torná-la competitiva em relação às transações alternativas eletrónicas.
- Estudos preliminares de Adsorventes Lenhocelulósicos para a Remoção de CefalosporinasPublication . Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula; Araújo, R.; Lopes, Ana Rita Valente da Cruz; Weber Macena, Morgana; Esteves, BrunoIntrodução: A Acacia dealbata foi explorada como biosorvente para remover cefalosporina de soluções aquosas. Este estudo procura demonstrar a viabilidade de utilizar materiais lenhocelulósicos de baixo custona remoção de poluentes, valorizando resíduos de outras indústrias e reduzindo o impacto ambiental associado. Objetivo: O objetivo pretendeu avaliar a capacidade dos resíduos de acácia em adsorver a cefalosporina, analisando o seu potencial de adsorção e os modelos cinéticos envolvidos, de forma a explorar o seu uso no tratamento de águas. Métodos: Esta revisão foi conduzida utilizando uma abordagem sistemática para identificar, analisar e sintetizar a literatura relevante sobre a presença e o impacto dos antibióticos cefalosporínicos em ambientes aquáticos. Paralelamente, foram realizados testes de adsorção utilizando soluções de cefalosporina com concentração de 15 mg L⁻¹, variando o tempo de agitação entre 10 e 120 minutos. A cinética de adsorção foi avaliada com base nos modelos de pseudo-primeira ordem, pseudo-segunda ordem, Elovich e difusão intrapartícula. A adsorção foi analisada através de espectrometria UV-Vis, onde se identificou um pico de absorção característico a 240 nm. Resultados: Os resultados indicaram que o modelo de pseudo-primeira ordem apresentou o coeficiente de determinação mais elevado (R² = 0,991), sugerindo que o mecanismo predominante é a adsorção física. Esta análise confirmou a capacidade da acácia em adsorver cefalosporinas, evidenciando o seu potencial como biosorvente. Conclusão: Este estudo sublinha a relevância dos biosorventes, como a Acacia dealbata, no tratamento de poluentes da indústria farmacêutica. A utilização de materiais sustentáveis oferece uma solução promissora para o tratamento de águas, abrindo caminho para futuras aplicações no campo da biossorção.
- Characterization of Lignocellulosic Byproducts from the Portuguese Forest: Valorization and Sustainable UsePublication . Macena, Morgana; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula; Grosche, Lucas; Santos-Vieira, Isabel; Esteves, Bruno; Pereira, HelenaThe increasing emphasis on environmental sustainability has placed biomass as a versatile and renewable resource, while the management and disposal of forest byproducts remain a significant challenge. This study explores the valorization of forest biomass residues derived from Pinus pinaster, Pinus pinea, and the invasive species Acacia dealbata, with a focus on their potential application as bioadsorbents. A comprehensive physicochemical characterization was conducted for different biomass fractions (leaves, needles, and branches of varying diameters). Leaves and needles contained higher amounts of extractives (from 7.7% in acacia leaves to 18.8% in maritime pine needles) and ash (3.4 and 4.2% in acacia leaves and stone pine needles, respectively), whereas branches contained more holocellulose (from 59.6% in P. pinea small branches to 79.2% in P. pinaster large branches). ATR-FTIR and pHpzc analyses indicated compositional and surface charge differences, with higher pHpzc values in A. dealbata relative to Pinus. TG analysis showed that acacia large branches degraded at a lower temperature (320 °C) compared to Pinus species (440–450 °C). Overall, the findings highlight the suitability of these underutilized forest byproducts as bioadsorbents, contributing to the advancement of circular economy practices.
- Kinetics and Isotherm Study of Ceftriaxone Removal Using Functionalized Biochar Combined with PhotocatalysisPublication . Cruz-Lopes, Luísa ; Araújo, Rodrigo ; Lopes, Ana Rita ; Moles, Samuel ; Romero-Sarria, Francisca ; Esteves, BrunoThe increasing presence of antibiotics such as cephalosporins in wastewater represents a significant environmental risk. These compounds are excreted in large quantities, and conventional wastewater treatment plants are often ineffective at their removal. Consequently, the development of more sustainable and efficient treatment technologies is essential. In this study, the removal of cephalosporins from aqueous solutions was evaluated through adsorption using pine bark biochar, photocatalysis with TiO2, and a combination of both processes. Kinetic experiments were conducted with cephalosporin solutions (15 mg/L), employing 150 mg/L of biochar, 100 mg/L TiO2, or their combination, under continuous stirring and/or UV-vis irradiation. Samples were collected at 0 and 120 min and analyzed via UV-vis spectrophotometry. Adsorption isotherms were established for initial cephalosporin concentrations ranging from 5 to 50 mg/L. The biochar alone achieved a removal efficiency of 94.2% after 120 min. Photocatalysis with TiO2 alone resulted in 75% removal, while the combined approach reached 95.9%, indicating a synergistic effect between adsorption and photodegradation mechanisms. Kinetic data fitted the pseudosecond-order model, and the Langmuir isotherm provided the best correlation, suggesting monolayer adsorption. These findings demonstrate that pine bark biochar, whether used independently or in combination with TiO2, constitutes an eco-friendly, effective, and low-cost alternative for the removal of antibiotics from wastewater, while simultaneously contributing to the valorization of forestry residues
- Valorization of Pinecones as Biosorbents for Environmental Remediation of Zn-Contaminated WastewatersPublication . Macena, Morgana; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula; Grosche, Lucas; Esteves, Bruno; Santos-Vieira, Isabel; Pereira, HelenaEmpty pinecones are a largely available byproduct of Pinus pinea L. nut production, mostly concentrated in the Mediterranean area; e.g., in Portugal, around 70,000 tons of pinecones are produced annually. One valorization line for residual biomass is its use as biosorbents for the removal of contaminants in effluents and water courses which are an increasing environmental problem. This study explores the biosorbent potential of pinecones to remove zinc ions from aqueous solutions. We analyzed the morphology and chemical composition of pinecones (9.4% extractives, 37.0% lignin, 68.6% holocellulose, 1.4% ash). The effect of pH and adsorbent dose on the adsorption process was studied, as were the sorption kinetics and isotherms. The pinecones showed good potential to remove Zn ions, with 96% removal at pH 7 and a maximum adsorption capacity of 7.92 mg g−1 . The process followed the Freundlich isotherm model, indicating a heterogeneous surface and multilayer adsorption, and the pseudo-second-order kinetic model, suggesting chemisorption as the dominant mechanism. The use of pinecones as bio-adsorbent is therefore a green and low-cost alternative for environmental remediation and biomass waste management.
- Enhancing Pinus pinaster Wood Durability Through Citric Acid ImpregnationPublication . Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula; Mariana Sell; A. Lopes, Rogério; Esteves, BrunoCitric acid (CA), a naturally occurring compound in fruits, mainly citrus, has gained attention for its eco-friendly potential in wood modification. Through esterification, citric acid reacts with wood polymers to form bonds that improve adhesion, dimensional stability, and durability while reducing moisture absorption and susceptibility to decay. This study evaluated the efficacy of CA as an eco-friendly wood treatment. Wood samples were treated with solutions at varying concentrations (5%, 10%, and 15%) and assessed for dimensional stability, mechanical properties, biological resistance, and ecotoxicity. CA treatments significantly improved dimensional stability, with higher concentrations yielding greater weight percent gain (WPG) and anti-swelling efficiency (ASE). Biological tests demonstrated exceptional termite resistance, with no survival and minimal mass loss in treated samples at higher concentrations. Similarly, fungal resistance improved, as citric acid inhibited fungal growth. Ecotoxicity tests showed relatively low phytotoxicity, with some decrease in germination indices (GI) at higher CA concentrations. These findings highlight CA as a sustainable wood treatment for enhanced durability and biodegradation resistance in construction and outdoor applications.
- Enhanced Properties of Cryptomeria japonica (Thunb ex L.f.) D.Don from the Azores Through Heat-TreatmentPublication . Esteves, Bruno; Nunes, Lina; A. Lopes, Rogério; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa PaulaThis study evaluates the chemical, physical, mechanical, and biological properties of untreated and heat-treated Cryptomeria japonica (Thunb ex L.f.) D.Don wood from the Azores, Portugal. Heat treatment was performed at 212 ◦C for 2 h following the Thermo-D class protocol. Chemical analysis revealed an increase in ethanol soluble extractives and lignin content after heat treatment, attributed to hemicellulose degradation and condensation reactions. Dimensional stability improved significantly, as indicated by reduced swelling coefficients and higher anti-swelling efficiency (ASE), particularly in the tangential direction. Heat-treated wood demonstrated reduced water absorption and swelling, enhancing its suitability for applications requiring dimensional stability. Mechanical tests showed a decrease in bending strength by 19.6% but an increase in the modulus of elasticity (MOE) by 49%, reflecting changes in the wood’s structural integrity. Surface analysis revealed significant color changes, with darkening, reddening, and yellowing, aligning with trends observed in other heat-treated woods. Biological durability tests indicated that both untreated and treated samples were susceptible to subterranean termite attack, although heat-treated wood exhibited a higher termite mortality rate, suggesting potential long-term advantages. This study highlights the impact of heat treatment on Cryptomeria japonica wood, emphasizing its potential for enhanced stability and durability in various applications.