Browsing by Author "Macena, Morgana"
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- 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.
- Consumer perspective about plastic food packagingPublication . Macena, Morgana; Cruz-Lopes, Luísa; Guiné, RaquelPlastic materials have been increasingly used for food in the latest decades, due to the many advantages associated with these materials: they offer considerable design flexibility; they are cheap and lightweight; and they have a wide range of physical and optical properties important to preserve the foods. Plastics made from petroleum are not degradable and are discarded in the environment, originating huge environmental problems, threatening all forms of life by entering the food chains. This work focused on the perspectives of Portuguese consumers concerning plastic food packaging and its consequences for the environment and the ecosystems. The research included a questionnaire survey applied to a sample of 385 adult citizens. The results showed that the participants are inclined to reflect about the negative impact of plastic packaging on the ecosystems and about 40% admit that they sometimes do not buy plastic while 30% try to use alternative materials. An important percentage, over 80%, are in favour of prohibition to use plastic utensils of single usage and the limitation in the use of plastic bags to carry goods and foods in particular. Most participants revealed a good knowledge about recycling and are favourable to the use of recycled materials. Nearly 90% of the participants separate the different types of waste aimed at recycling. Although shifting the usage of plastic towards more sustainable options has been facing some difficulties, it is also verified that consumers are becoming more worried about the impact of their choices on the sustainability of ecosystems and the whole planet Earth.
- Ideal pH for the adsorption of metal ions Cr 6 + , Ni 2 + , Pb 2 + in aqueous solution with di ff erent adsorbent materialsPublication . Cruz-Lopes, Luísa; Macena, Morgana; Esteves, Bruno; Guiné, RaquelIndustrialization increases the number of heavy metals released into the environment. Lead ( Pb 2 + ) , nickel ( Ni 2 + ) and chromium ( Cr 6 + ) are among these toxic metals and cause irreversible e ff ects on ecosystems and human health due to their bio - accumulative potential. The decontamination through adsorption processes using lignocellulosic wastes from agricultural and/or forestry processes is a viable solution. Hence, this work aimed at studying the e ff ect of pH on the biosorption of the metal ions using four di ff erent by - product materials: walnut shell, chestnut shell, pinewood and burnt pine - wood. These experiments were conducted with solutions of the three heavy metals in which the adsorbents were immersed to measure the rate of adsorption. A range of pH values from 3.0 to 7.5 was used in the experiments, and the concentrations were determined by atomic absorption. The results showed di ff erent behaviour of the biosorbent materials when applied to the di ff erent metals. The lead adsorption had an ideal pH in the range of 5.5 – 7.5 when the walnut shell was used as an adsor - bent, corresponding to values of adsorption greater than 90%, but for the other materials, maximum adsorption occurred for a pH of 7.5. For the adsorption of chromium, the pH was very heterogeneous with all adsorbents, with optimal values of pH varying from 3.0 ( for chestnut shell ) to 6.5 ( for walnut shell and wood ) . For nickel, the best pH range was around pH 5, with di ff erent values according to the lignocellulosic material used. These results indicate that the tested biosorbents have the potential to decon - taminate wastewater in variable extensions and that by controlling the pH of the solution; a more e ffi cient removal of the heavy metals can be achieved.
- Lignocellulosic Byproducts as Bio-Adsorbents for Lead RemovalPublication . Macena, Morgana; Pereira Helena; Grosche, Lucas; Esteves, Bruno; Santos-Vieira, Isabel; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa PaulaWater pollution by toxic metals, especially by lead ions, is a serious environmental concern due to these metals’ persistence, bioaccumulation, and toxicity. Aiming to reduce metal concentrations to non-toxic levels, this study analyzed the removal of lead from water through adsorption with bio-adsorbents. The adsorbent potential of the following four lignocellulosic byproducts were tested: walnut and chestnut shells, pine wood, and burnt pine wood. Removal rates of 97–99% were achieved at optimized conditions, i.e., at a pH of approximately 7, adsorbent dose of 4 g L−1, and 12 h of reaction. The BET specific surface area was between 1.74 and 4.85 m2 g−1. The pore size of the wood bio-adsorbent was 26.54 nm, and those of the remaining materials were between 5.40 and 7.33 nm. With R2 = 0.998–1.000, the kinetics fit the pseudo-second-order model better, suggesting that chemisorption is the dominant mechanism. Both Langmuir and Freundlich isothermal models fit the data well, with R2 = 0.946–0.999. It can be concluded that all the bio-adsorbents tested have the potential to efficiently remove lead ions from water.
- Lignocellulosic Materials Used as Biosorbents for the Capture of Nickel (II) in Aqueous SolutionPublication . Cruz-Lopes, Luísa; Macena, Morgana; Esteves, Bruno; Santos-Vieira, IsabelFour lignocellulosic materials (walnut shell, chestnut shell, pine wood and burnt pine wood) were analyzed as biosorbents to remove nickel ions in aqueous solution. The optimal pH condition was determined. Due to this, a range of different pHs (3.0 to 7.5) was tested. The adsorption isotherms and kinetics were established. To plot Langmuir and Freundlich isotherms, batch adsorption tests were made with variable nickel concentrations (5 to 200 mg L−1). The pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models were used to describe the kinetics, batch adsorption tests were carried out with 25 mg L−1 of nickel solution and agitation time varied from 10 to 1440 min. The specific surface area of the different materials was between 3.97 and 4.85 m2g−1 with the exception for wood with 1.74 m2g−1. The pore size was 26.54 nm for wood and varied between 5.40 and 7.33 nm for the remaining materials. The diffractograms analysis showed that all the lignocellulosic materials presented some crystalline domains with the exception of burnt pine wood which was completely amorphous. The best pH was found to be around 5.0. At this pH the adsorption was higher for chestnut shells, walnut shells, burnt pine wood and wood, respectively. All samples fitted the Langmuir model well, with R2 of 0.994 to 0.998. The sorption kinetics was well described by the pseudo-second order equation with R2 between 0.996 and 1.00. No significative differences on the surface of the materials before and after adsorption could be observed by SEM. Finally, all materials tested were able to remove nickel ions in aqueous solution.
- Perceptions and knowledge regarding quality and safety of plastic materials used for food packagingPublication . Macena, Morgana; Carvalho, Rita; Cruz-Lopes, Luísa; Guiné, Raquel P. F.The objective of this study is to investigate the consumer perceptions about quality and safety of foods packed in plastic, as well as the impact of plastic materials on human health. To carry out the study, a questionnaire survey about the consumption habits and knowledge about plastic packaging was conducted to a sample of 487 Portuguese adult citizens. The results revealed that most respondents (81%) think about food safety and quality when purchasing foods. Additionally, it was found that the consumer’s knowledge about the toxicity of components possibly migrating from the plastic packaging to the food is still limited (only 46% of participants). However, other negative effects of plastics well known to consumers include environmental pollution and marine fauna degradation (67 and 82% of participants, respectively). Thus, it was concluded that the Portuguese population need to be further educated about the toxicity of some chemical compounds present in plastic packaging, which can be ingested by migrating to the food or which can be absorbed from the environmental microplastics resulting from incorrect disposal.
- Plastic Food PackagePublication . Guiné, Raquel P. F.; Macena, Morgana; Cruz-Lopes, Luísa
- Plastic Food Packaging: Perceptions and Attitudes of Portuguese Consumers about Environmental Impact and RecyclingPublication . Macena, Morgana; Carvalho, Rita; Cruz-Lopes, Luísa; Guiné, RaquelThe use of plastics for packaging has some advantages, since they are flexible and inexpensive. However, most plastics are of single use, which, combined with low recycling or reuse ratios, contributes substantially to environmental pollution. This work is part of a project studying the habits of Portuguese citizens concerning plastic food packaging and focuses on aspects related to sustainability. The survey was carried out via an online questionnaire about sustainability, recycling, and knowledge of the effects of plastic materials or their residues on the environment. The results were obtained based on a statistical analysis of the data. The participants tend to think about the negative impact of plastic packages on the environment; 39% sometimes do not buy plastic; and 30% try to look for alternatives. A substantial fraction, 81%, support the avoidance of plastic utensils and reduction in the use of plastic bags. Most participants have a good knowledge of recycling and strongly agree with the use of recycled materials, and 87% of respondents practice separation of different types of waste for recycling. Changing plastic consumption habits has not been an easy task. Nevertheless, it is expected that society will increasingly move toward sustainable habits, questioning its actions and considering their impact on the environment.
- 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.