Resumo em Inglês:

Porphyrinoid compounds such as chlorins and bacteriochlorin have currently been widely studied to remedy health problems, develop new technologies, apply in solar cells, and decontaminate food, aiming for sustainability. Its wide applicability demonstrates the potential of these derivatives to solve society’s problems. Thus, this work seeks to understand more about the reactivity and properties of these derivatives. In this way, structural changes were made to chlorophyll, giving rise to three chlorin compounds (1-3), and also to bacteriochlorophyll, giving rise to three bacteriochlorins (4-6). The experimentally obtained results were analyzed by infrared and UV-Vis spectroscopy and the experimental spectroscopic data were compared with data obtained theoretically with Gaussian 09 software, using density functional theory (DFT), such as B3LYP and CAM-B3LYP. After the analyses, it was observed that the data obtained experimentally are quite similar to those obtained theoretically. Thus, it is possible to demonstrate that theoretical calculations are useful tools and can help predict molecules, often avoiding the synthesis of a given molecules in the laboratory, minimizing the use of reagents and solvents and thus contributing to sustainability.

Resumo em Inglês:

A method was developed and validated for the simultaneous quantification of pesticides carbendazim (CBZ), diuron (DI) and carbofuran (CF) in surface water using a sustainable, handmade, and low-cost composite electrode (CE) based on graphite and polycaprolactone (PCL). The cyclic voltammetric (CV) results showed a quasi-reversible oxidation peak for CBZ around +0.76 V, and an irreversible oxidation peak for DI and CF at +0.88 and +1.32 V, respectively. Under optimized conditions, the anodic peak currents were proportional over ranges of 5.0-1059.0 µg L−1 for the binary analysis of CBZ and DI, with detection limits of 4.0 and 18.0 µg L−1, and limits of quantitation of 13.0 and 55.0 µg L−1, respectively. The proposed electrochemical method also exhibited good repeatability (n = 10) and intermediate precision (n = 3), with a relative standard deviation of 5%. In addition, the method successfully determined CBZ and DI in surface water samples without any sample pretreatment. Comparison with the reference chromatographic method ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) showed no significant differences at a 95% confidence level, demonstrating the applicability of the method. Additionally, the composite electrode offers advantages such as low cost, easy manufacturing, and simple operation.

Resumo em Inglês:

The 2019 oil spill in Brazil caused widespread contamination in the Brazilian coast, posing risks to both animal and human health through seafood consumption. Therefore, this study aimed to evaluate seafood samples from different locations impacted by the oil spill. For this purpose, 44 samples underwent extraction processes for the determination of polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylene (BTEX). The BTEX compounds were undetected above the limit of detection (LOD) of 0.02 µg g−1 of wet mass. The LOD and limit of quantification (LOQ) for the PAH were 2 and 5 ng g−1, respectively. The range of recovery of PAH obtained from spiking was 39 ± 15.8 to 84 ± 5%. The concentration of PAH in the samples ranged from < LOQ to 17.5 ng g−1. Results suggested higher contamination levels in samples collected in Rio de Janeiro, with quantifications for 11 of the evaluated PAH. Benzo[a]pyrene and dibenzo[a,h]anthracene, both potentially carcinogenic, were found in 32 and 14% of samples, respectively. Therefore, additional coastal monitoring is advised to ensure seafood safety, given the potential PAH carcinogenicity, which could strain the Brazilian public health system.

Resumo em Português:

Hospital laundry is an important source of environmental pollution because its effluent contains high loads of organic matter and microorganisms. Conventionally, the treatment is carried out using aluminum sulfate, a low-cost and highly efficient coagulant that is related to secondary contamination due to the generation of non-biodegradable sludge, its ability to accumulate metals and toxicity. Aiming for sustainable alternatives, the efficiency of tannin from the natural coagulant and Moringa oleifera seed was evaluated in relation to aluminum sulfate, seeking to adapt the color and turbidity parameters and determine the antimicrobial activity of the seed. Using a concentration of 100 mg L-1 of aluminum sulfate, 97.4 and 93.95% of color and turbidity removals in the effluent were obtained, respectively. With 50 mg L-1 tannin showed an efficiency of 84.96% for color removal and 89.75% for turbidity. Tests were also carried out with Moringa oleifera seeds using saline seed extract, crushed seeds and aqueous seed extract, with a reduction in conductivity by more than 99%, removing pollutant ions for the saline extract. Of the methodologies used, the best result was obtained with the aqueous extract, achieving removals of 89.63% of color, 78.33% of turbidity, and inhibition of more than 98.1% of microorganism growth.

Resumo em Português:

The continuous global production of polyurethane (PU) and its environmental persistence generate negative impacts on ecosystems, driving the search for sustainable handling solutions, specifically the use of enzymes. Therefore, this study seeks to elucidate the understanding of the enzymatic degradation mechanism of polyurethanase esterases A and B (PueA and PueB) applied to PU-MDI (methylene diphenyl diisocyanate). In this sense, previously built structures were used and dockings were carried out for the PueA and PueB complexes. The results indicate binding scores of -10.743 and -9.587 kcal mol-1 for PueA and PueB, respectively. Furthermore, the complexes were then subjected to molecular dynamics simulations (MD) for 500 ns in triplicate, showing a good interaction between the enzymes and the PU-MDI. Finally, a QM/MM (quantum mechanics/molecular mechanics) simulation, starting with an adequate snapshot from classical MD was carried out, and a relaxed scan was performed to obtain the occurrence coordinates, followed by umbrella sampling to obtain the free energy profile of the systems. The results indicate that the PueA and PueB reaction mechanisms occur in two steps, with determining energy barriers of 11.95 and 15.10 kcal mol-1, respectively, indicating that these enzymes may be used to degrade PU.

Resumo em Inglês:

At sewage treatment plants, sludge management remains a bottleneck, requiring efficient and cost-effective solutions for treating this solid byproduct. It is known that the presence of plants can accelerate the sludge drying process, as a result, vertically flowed constructed wetlands (VFCWs) have been evaluated as alternatives to traditional drying beds. Though, for better applicability of this technology, this study premised on evaluating greenhouse gas (GHG) emissions in VFCWs constructed for anaerobic sludge treatment. To compare GHG emissions across different seasonal conditions, three configurations were tested: four units planted with Tifton-85 grass (Cynodon spp.), four units planted with elephant grass (Cenchrus purpureus), four control units without vegetation presence, with four sludge loading rates in each configuration: 75, 100, 150, and 200 kg TS (total solids) m-2 year-1. Higher sludge loading rates led to increased methane emissions, with emissions escalating during the rainy season. Methane emissions decreased towards the end of the resting period. The presence of vegetation reduced methane emissions mainly during the resting period due to increased aeration of the units. The conditions that would provide lower GHG emissions would be with loads of up to 100 kg m-2 year-1, in units planted with Tifton grass.

Resumo em Português:

The extraction and processing of ornamental rocks generate a very significant amount of waste, representing an environmental and public health problem. The residue is a fine-grained compound by rock powder and inputs used in the processing process have a potential economic value. The present study was carried out to evaluate the efficiency of the waste generated in the discoloration of an aqueous solution containing methylene blue dye, such as alternative for treating textile effluents. The samples were characterized by X-ray diffraction, inductively coupled plasma optical emission spectroscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The catalytic properties of the samples were evaluated in the Fenton and photo Fenton reactions at pH 3 and natural pH. The best decolorization efficiency (≈ 95%) was achieved using the GRM catalyst at pH 3, after 5 min of photo Fenton reaction. Importantly, owing to its excellent structural and chemical stability, the samples showed a decolorization efficiency above 95% after 5 consecutive cycles of 30 min of reaction. This innovative strategy not only offers a new prospect for the rational disposal of abrasive mud waste, but also contributes to minimizing environmental impacts, promoting sustainable development in the stone industry.

Resumo em Inglês:

The discharge of dye contaminant malachite green (MG) into the water environment will seriously affect human health. In this paper, Fe3O4@SiO2 magnetic nanoparticles were prepared as catalysts using co-precipitation and sol-gel methods, which accelerated the removal of MG by H2O2 over a wide pH range with remarkable results. The degradation mechanism is consistent with the Fe2+-H2O2 Fenton system and the pseudo-first-order kinetic model, and the degradation rate can be increased by 179 times compared with not using this catalyst. When pH ≥ 5, Fe3O4@SiO2 catalyzes H2O2 oxidation of MG for only 10 min to achieve a high degradation rate of 99%, and less than 3 min to achieve a 95% degradation rate. The catalyst can be quickly separated and easily regenerated under an external magnetic field, and a degradation rate of 82% can still be reached after 5 uses. In a word, this work has successfully developed an efficient, green and economic MG wastewater treatment technology.

Resumo em Português:

Personal hygiene products, such as UV filters, are consumed daily and released at sewage treatment plants. The presence of these compounds in aquatic environments may cause concern, as their impacts are not yet fully known. Biofilms can be an innovative and simple tool for monitoring the bioaccumulation of contaminants such as UV filters in aquatic environments. The present work aimed to determine and evaluate the potential of bioaccumulation of these compounds in biofilm and in the surface waters of the Barigui River. The determination of contaminants in environmental matrices was performed by liquid chromatography coupled to triple-quadrupole mass spectrometry (LC-MS/MS). The validation of the methodology used was based on the acceptance criteria of the National Institute of Metrology, Quality and Technology (Inmetro). The results obtained in the samples ranged from the maximums of 5.85 μg L-1 of benzophenone-1 for water samples to 1907.40 μg kg-1 of benzophenone-3 for biofilm. The study showed that biofilm is a very useful new tool in environmental monitoring, mainly due to the bioaccumulation capacity of UV filters.

Resumo em Português:

This study investigated the preparation of a thermoplastic starch-based (ATP) biocomposite reinforced with eucalyptus fibers (FE), focusing on how fiber size affects the properties. The natural fibers were chemically processed using alkaline and bleaching treatments of eucalyptus bark. Subsequently, they were characterized by infrared spectroscopy (FTIR) and X-ray diffraction (XRD) to evaluate alterations in fiber composition and crystalline structure. Samples of biocomposites were prepared with a fixed fiber content (20 wt.%) and variations in particle size (dp): ATP/FE600 (600 μm ≤ dp < 1180 μm), ATP/FE250 (250 μm ≤ dp < 600 μm), and ATP/FE75 (75 μm ≤ dp < 250 μm). The samples were characterized by optical and scanning electron microscopy, mechanical tests, moisture absorption, and swelling analysis. Results indicated significant effects of fiber size on the biocomposite properties. Notably, the larger fibers present in ATP/FE600 exhibited superior tensile strength and elastic modulus, while this sample demonstrated reduced moisture absorption and swelling tendencies. Microscopic images revealed enhanced matrix-fiber adhesion in ATP/FE600, highlighting the importance of proper fiber size. The optimization of fiber size emerges as a relevant strategy for improving the mechanical attributes and mitigating moisture/water absorption tendencies in starch-based thermoplastic biocomposites, contributing to sustainable and high-performance materials.

Resumo em Inglês:

Green Chemistry aims to prevent pollution resulting from activities in the chemical sector. Generally, laboratory activities generate pollution because toxic substances are used to perform analyses, which produce waste once the analyses are completed. This study aimed to monitor the quality of the Uberaba River using more sustainable and non-destructive techniques through orbital remote sensing and to develop methods for estimating water quality at reduced costs using orbital sensors and machine learning. The values of water quality parameters, such as iron, nitrate, chloride, total phosphorus, and total nitrogen, were studied between 2018 and 2023. Orbital sensing data (spectral bands and vegetation indices) were taken from the exact geographic coordinates of the collection points. Data were analyzed using Pearson’s correlation coefficient and random forest regression analysis. The study concludes that it is possible to perform orbital remote sensing by estimating water quality through random forest regression, correlating the information obtained from Sentinel-2 images with the values of these parameters. This approach is a sustainable technique that does not generate waste and represents a 100% saving compared to conventional chemical analyses.

Resumo em Inglês:

The growing awareness of health and well-being has led to increased consumption of healthy foods, such as exotic fruits, owing to their high nutritional value and global availability. However, the production and trade of exotic fruit presents significant challenges, particularly with regard to increasing supply and ensuring food safety concerning pesticide residues. This review examines modern analytical strategies employed to determine pesticide residues in exotic fruits. It is evident from the literature that ultra-high performance liquid chromatography and gas chromatography techniques, coupled with tandem mass spectrometry, remain the methods of choice for determining pesticide residues. For sample preparation, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method, renowned for its simplicity and efficiency, is extensively utilized in its original form as well as in acetate, citrate, and other modified versions to enhance its effectiveness. Developing these analytical methods is crucial for ensuring the safety of exotic fruits, protecting consumer health, and facilitating exports to global markets. Further advancements in this field are essential to overcome the challenges posed by producing and trading exotic fruits, thereby promoting food safety and public health. This review also discusses the occurrence of pesticides in exotic fruits.

Resumo em Inglês:

Metals, pharmaceuticals, personal care products, pesticides, and dyes constitute contaminants widely detected in aquatic ecosystems. Adsorption is an important technology for addressing these noxious contaminants in water systems. Its widespread employment stems from its uncomplicated design, environmentally benign nature, heightened sensitivity to contaminants, and mechanical robustness. These inherent advantages render it a highly promising solution for such challenges. Within this framework, biochar embodies key physicochemical properties akin to activated carbon, the foremost adsorbent globally recognized for its efficacy in water contaminant removal. Moreover, biochar derives from the repurposing of biomass waste, thereby presenting an opportunity to enhance the value chain of numerous agricultural byproducts across Brazil. Therefore, this review article aims to present the most commonly studied lignocellulosic residues from Brazil as adsorbents, the methods used to convert them into biochar, the factors influencing the adsorption of contaminants on biochar, and their environmental applications. The main results related to lignocellulosic biomass were presented, including sugarcane, soybean, corn, rice, cotton, coffee, açaí, tucumã, coconut, Brazil nut, cupuaçu, nuts, murumuru, orange, cassava, banana, malt, macaúba, and guava. It was concluded that chemical activation is more common than physical activation, especially using ZnCl2. Finally, the materials have been employed for the removal of metals and a few organic contaminants, mainly dyes, from synthetic solutions.

Resumo em Inglês:

The objective of this work is to add the serious inconveniences that the pandemic brought with the social difficulties in education and health. Important institutions generated the 2030 Agenda that contains Sustainable Development Goals to be implemented in the period 2016-2030. These 17 objectives have been outlined to encompass the wide range of societal challenges, such as economic and environmental, that influence social communities (family, school). This work will focus on Sustainable Development Goals 3 and 4, respectively, which can only be met if citizens take into their hands the education that plays an important role in having a healthy life. This will consider the teaching and learning of sustainable chemistry in social contexts such as the classroom, the family, the links between students and teachers that cause diseases. The regrouping of students according to the work levels achieved during the crisis or the development of personalized proposals to intensify work processes is valid. This leads to living with decisions that will have good or bad results, which is why each region has different responses to the crisis experienced.

Resumo em Português:

The knowledge of chemistry connected to environmental problems and sustainable development can provide an opportunity for dynamic, investigative, and directed teaching towards the recognition of chemistry itself as a science and social practice. From this perspective, this work aimed to investigate how discussions involving topics related to environmental education are conducted by researchers and/or professionals in chemical education, based on articles published in the journal Química Nova na Escola (QNEsc). The selection of articles was made considering publications from QNEsc between the years 1995 and 2022, focusing on terms such as environmental education, environment, pollution, environmental aspects, sustainability, and sustainable development present in the title, abstract, and/or keywords of the published articles. The selected texts were analyzed using Iramuteq software, applying correspondence factorial analysis (CFA), hierarchical descendant classification (HDC), similarity analysis, and word cloud using their respective abstracts. The data show that topics such as water, pesticides, waste, and plastic materials (polymers) were the most addressed by the publications, indicating a path that seeks to present and discuss proposals that value the need for sustainable actions, addressing environmental issues that directly impact the way humans use natural resources in the present and future.