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- Plastic Food PackagePublication . Guiné, Raquel P. F.; Macena, Morgana; Cruz-Lopes, Luísa
- 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.
- 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.
- 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.
- Competitive Adsorption of Metal Ions by Lignocellulosic Materials: A Review of Applications, Mechanisms and Influencing FactorsPublication . Weber Macena, Morgana; Helena Pereira; Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula; Lucas Grosche; Esteves, BrunoThe rapid expansion of industrial and agricultural activities in recent years has significantly contributed to water pollution leading to a decline in water quality and the need for effective treatment and reuse strategies. Metal contamination in water bodies poses severe environmental and health risks, making the development of cost-effective and sustainable remediation methods essential. Among the various treatment approaches, biosorption using biological adsorbents has emerged as a promising alternative due to its low cost and high efficiency. However, while the adsorption mechanisms of single metals are well understood, the competitive interactions between multiple metal ions during the sorption process remain less explored. In this review, we analyze the competitive biosorption of metals in multi-metallic wastewater systems. Key factors influencing metal removal, such as pH, contact time, biosorbent dosage, and initial metal concentration, are discussed, along with the intrinsic properties of biosorbents and metal ions that affect sorption efficiency. Additionally, we highlight recent studies on agroforestry byproducts as effective biosorbents for metal removal, showcasing their potential for sustainable water treatment. Heavy metals pose significant risks even at low concentrations, necessitating robust regulations and advanced treatment technologies; biomass byproducts, as cost-effective biosorbents, can be optimized through pre-treatment, activation, pH and temperature control, and particle size reduction, while effectively manage