Abstract in English:

Given the extensive use of pesticides in modern times, residues are frequently detected in water samples. Therefore, this study developed and validated a method utilizing solid-phase extraction (SPE) with a polymeric sorbent for sample preparation in combination with ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The aim was to determine a variety of current-use pesticides (CUPs) in different types of water. The preconcentration step, employing the polymeric sorbent Oasis HLB (60 mg), combined with the high selectivity and sensitivity of the UHPLC-MS/MS analysis, enabled the multiclass determination of pesticide residues in water samples at very low concentrations. The proposed method underwent validation, demonstrating satisfactory linearity, precision, and accuracy. The accuracy results, determined through recovery assays at varying spike levels (0.04-0.4 μg L-1), ranged from 71 to 117%, with precision expressed as relative standard deviations consistently below 19%. The practical limits of detection and quantification for most compounds were 0.01 and 0.04 μg L-1, respectively. This method was effectively employed to analyze drinking water, artesian well water, dam water, and river water, leading to the detection of various pesticides at concentrations of up to 2.24 μg L-1.

Abstract in English:

Mixed oxides of pyrochlore structure of the type La2Zr2O7 and La2M0.3Zr1.7O7 (M = Fe or Ni) were synthesized through the modified proteic method and calcined at 900 °C for 2 h, this is a synthesis route not yet explored for materials with this structure and were characterized by X-ray diffraction, scanning electron microscopy images, point of zero charge (PZC) and specific surface area. Its abilities to remove pollutants from aqueous media by adsorption process were investigated using a model compound. Data analysis revealed that the synthesized materials correspond to the pyrochlore phase (La2Zr2O7). They present particulate morphology with grains of different sizes and pores in their structure. The results of the adsorption studies show that the materials are efficient adsorbents for the removal of model compound in aqueous media, with efficiency above 90%. The adsorption kinetics of the compound in the adsorbents was studied. The materials were applied in reuse studies five times and maintained high efficiencies, highlighting the better performance presented by the material without doping. The obtained adsorbents were also submitted to removal of contaminants of industrial effluent tests and compared with the silica gel and activated carbon materials and also proved to be promising materials.

Abstract in English:

Polybrominated diphenyl ethers (PBDEs) are persistent flame retardants widely used in everyday materials, with the potential to leach out and contaminate indoors and receiving waters. Despite their well-documented ecological risks, there has been limited reporting on PBDE levels in sediments from Brazilian freshwaters, motivating the monitoring of sediments from Paranoá Lake, in the Brazilian capital. After sampling, extraction, and analysis of congeners BDE-28, -47, -66, -85, -99, -100, -138, -153, and -154 by gas chromatography with electron capture detection, Σ9PBDE levels ranged from 3.9 ± 0.2 to 19 ± 1 ng g-1 dw, with higher concentrations attributed to effluent discharge from wastewater treatment plants (WWTPs), followed by the influence of storm drainage water contamination. The distribution of PBDE congeners suggested a predominant influence of the commercial pentaBDE formulation, likely DE-71. However, in points influenced by WWTPs, the prevalence of BDE-66 suggests biotic reductive debromination of high-brominated PBDE, possibly BDE-209, indicating the possible influence of the decabrominated formulation. The distribution of PBDEs in the environment, estimated using the EQC (equilibrium criterion) model, level I, indicated low concentrations in the water column, but also noteworthy levels in biota and sediment precursor materials. Finally, preliminary ecological risk assessment indicated the need for future further surveys.

Abstract in English:

In recent years, the Brazilian government has authorized several agricultural pesticides, increasing the possibility of pollution of different ecosystems and the food consumed by a large part of the population. The analytical determination of pesticides can be carried out using different techniques associated with various methods. Their development and validation have been based on obtaining better reliability, meeting the requirements of environmental legislation, and adapting to the principles of Green Chemistry. Thus, a chromatographic method was developed for the separation and determination of eight agricultural pesticides (aldicarb, ametrine, atrazine, bendiocarb, carbaryl, hexazinone, methiocarb, and methomyl) in compliance with Green Chemistry criteria, using ethanol as the mobile phase, which it is an ecologically less aggressive solvent. The developed method showed efficient separation and excellent results for green analysis metrics with high scores on the Eco-scale and good presentation in the National Environmental Methods Index (NEMI), Green Analytical Procedure Index (GAPI), and Analytical Greenness Calculator Metric (AGREE) pictograms. The validation parameters indicated the linearity of the method with good precision, selectivity, and sensitivity with detection and quantification limits in the ranges of 0.50 to 0.94 mg L–1 and 0.74 to 1.81 mg L–1, respectively.

Abstract in English:

It is essential to diversity energy sources for ensuring sustainability. While hydrogen is considered a promising energy storage medium, its potential hinges on the development of efficient photocatalysts for green production. In addressing this challenge, we evaluated the performance of a heterojunction system composed of non-stoichiometric molybdenum oxides (MoO3−x) and cadmium sulfide (CdS) quantum dots (QDs) for water splitting. MoO3−x were synthesized via gamma irradiation of the MoO3 in the presence of formic acid (FA), while CdS-MPA QDs were electrosynthesized. The heterojunction was formed through adsorption. The structural and electronic characterization revealed a progressive transformation from MoO3 to MoO3−x and MoO3−x/CdS-MPA QDs, demonstrating enhanced water-splitting performance. Upon evaluation, the study revealed a charge transfer mechanism, highlighting the significance of relative band positions between MoO3−x and CdS-MPA QDs in promoting eco-friendly hydrogen evolution and methanol processing. Thus, we suggest that the synergism between MoO3−x and CdS-MPA QDs semiconductors makes the heterojunction system a promising solution for photocatalytic production of hydrogen and oxygen.

Abstract in English:

Diffusive gradients in thin film (DGT) is an attractive method for dynamic studies of metal speciation. Conventional DGT devices consists of diffusion and binding layers that utilize a polyacrylamide hydrogel, a synthetic polymer considered toxic, for the determination of labile metals. In this work, a simple method for the preparation of DGT devices using environmentally friendly and sustainable materials was proposed. Consequently, the polyacrylamide hydrogel was replaced with agarose, a low-cost and non-toxic biopolymer. The modified DGT was employed to determine the labile concentrations of Cd, Cu and CrIII in natural waters. The diffusion coefficients (D) for agarose were determined with a diffusion cell. The obtained values of D ranged from 2.05 to 4.53 × 10−5 cm2 s−1. The relationships between diffusion mass and time were linear for all trace metals. The binding layer with Chelex-100® and agarose was evaluated in retention and extraction of metals. The elution factors were within the range of 0.775 and 0.86 for Cd, Cu and CrIII. The proposed device was evaluated through recovery tests. Recoveries were greater than 80%. DGT devices were deployed in the determination of labile metals in river water from Cará-Cará River (Paraná, Brazil). The concentration of labile species in Cará-Cará sample proceeded as follows: Cd > Cu ≥ CrIII. The results suggest that DGT devices with agarose can be effectively used for speciation analysis.

Abstract in English:

Marine pollution has become relevant for coastal conservation units and ecosystems of great ecological importance. This study validated analytical methods to investigate the occurrence of the emerging contaminants 17β-estradiol (E2), estrone (E1), estriol (E3), and 17α-ethinylestradiol (EE2) in surface waters and suspended particulate matter (SPM) from Guaratuba Bay, South Atlantic, Brazil. The analysis was performed by liquid chromatography coupled to a fluorescence detector (LC-FLD) after pre-concentration of surface water samples by solid phase extraction (SPE) or solid-liquid extraction for SPM samples. The recovery percentages were between 48 and 87%, and the coefficient of variation (CV) between 3 and 24% for SPM and from 64 to 107% (CV of 4 to 42%) for surface water. The method thus proved to be accurate and precise at the concentrations studied (ng g−1 and µg L−1). The concentration ranged from 10 to 177 ng L−1 in surface waters and from 392 to 4108 ng g−1 in SPM. E2, EE2, and E3 were found in SPM under different climatic conditions and population occupation. EE2 was determined in all sampling campaigns, especially in summer, when the number of tourists increases considerably. The presence of EE2 in the SPM of Guaratuba Bay warns for possible implications for the health of coastal environments.

Abstract in Portuguese:

The synthesis of Fe-MOFs (metal-organic frameworks) was conducted using a solution heat method, followed by characterization through XRD (X-ray diffraction), SEM (scanning electron microscopy), and TG (thermogravimetry) analysis techniques. Subsequently, the Fe-MOFs were employed for norfloxacin removal. The experimental findings demonstrate that theoretical simulations of norfloxacin adsorption by Fe-MOFs involved the application of pseudo-first kinetic model, pseudo-second kinetic model, and adsorption isotherm. Chemisorption was identified as the primary mechanism observed. Notably, a maximum adsorption capacity of 197.7 mg g-1 was achieved at pH 10. These results underscore the practical feasibility of utilizing Fe-MOFs in applications related to norfloxacin adsorption.

Abstract in Portuguese:

The use of agroindustry waste in the synthesis of bioadsorbents provides a solution to reduce the disposal of solid waste in the environment while increasing the added value of recovering locally sourced waste. However, technical and environmental issues must be considered when selecting the appropriate synthesis method to avoid creating a new environmental impact and evaluate the feasibility of applying the method. In this work, yellow mombin, guava and mango seeds were used to synthesize bioadsorbents capable of removing cadmium(II) in solution. The materials were characterized according to their chemical composition, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and evaluated by adsorption kinetics tests. Energy analysis of biomass processing was performed by life cycle analysis (LCA). The bioadsorbents presented typical characteristics of lignocellulosic biomass, with the presence of functional groups favorable to the adsorption of metals and were effective in removing cadmium(II), with efficiency of 95.7, 92.4 and 60.2%, for BSG (guava seed bioadsorbent), BSC (yellow mombin seed bioadsorbent) and BSM (mango seed bioadsorbent), respectively. The error functions provided a more appropriate criterion for analyzing the kinetic data. The methodology proposed in this work is simple to implement and has a low estimated energy demand, therefore being promising for application in small fruit processing industries in the semi-arid region of Bahia.

Abstract in Portuguese:

The aim of this study was to evaluate the ecotoxicity of desensitizing and whitening toothpastes against aquatic and terrestrial bioindicators. This is an in vivo ecotoxicity study. Ten different toothpastes were selected. Toothpaste without detergent and fluoride was negative control 1. Sea salt solution, mineral water and distilled-deionized water were second negative control. Toothpaste slurries were prepared at a ratio of 1:2, 1:3, 1:10 and 1:30 (w/w). The immobility/mortality test was carried out on Artemia salina L. The root growth test was carried out to obtain the percentage of relative growth and inhibition on Allium cepa L. pH of the slurries were determined. The ANOVA (analysis of variance) and Tukey’s test was performed (p < 0.05). There was mortality in all Artemia nauplii exposed to desensitizing and whitening toothpastes. A significant reduction in the length of the roots of the bulbs exposed to all the slurries was observed. The percentage of inhibition was greater than 50%. Desensitizing and whitening toothpastes showed significant ecotoxicity against A. salina and A. cepa, with potential negative environmental impact of toothpastes on aquatic and terrestrial ecosystems.

Abstract in English:

In the present work, we developed an experimental class for undergraduate students concerning the linear synthesis of 2-phenylimidazo[1,2-α]pyridine through mechanochemical techniques. This approach aims to conceptualize the green chemistry principles through a safe, robust, atom-economic, energy-efficient, and solvent-free method for preparing these classes of compounds by manual grinding and vortex mixing. The methodology was easily applied in experimental classes for chemistry students and could be easily expanded to other courses such as pharmacy and biotechnology.

Abstract in Portuguese:

The Sustainable Development Goals (SDGs) provide a comprehensive framework to guide actions towards a more sustainable future, emphasizing the need for sustainable production and consumption patterns (SDG 12), urgent measures to combat climate change and its impacts (SDG 13), and ensuring inclusive, equitable, and quality education (SDG 4). In this context, environmental education (EE) becomes crucial to empower present and future generations to address complex environmental challenges. Promoting EE can be enhanced through Chemistry education, encouraging the use of biomass as a primary energy source, a significant ally in addressing the SDGs. This study integrates experimental and educational chemical knowledge on the pyrolysis reaction of black pepper waste, aiming at higher education in Chemistry in an Environmental Chemistry class at Federal University of Espírito Santo. It aims to provide an in-depth understanding of chemical kinetics, connected to sustainable development through the theoretical-methodological strategy of problematized experimental activity (PEA). The developed PEA comprised five theoretical-experimental classes, including thermogravimetric analysis (TGA) simulation and pyrolysis furnace testing. The results indicate significant learning in Chemical Kinetics and themes related to the pyrolysis process associated with sustainable development, highlighting the contribution of the utilized PEA.

Abstract in English:

(S)-Pyroglutamic acid is a heterocyclic amino acid derivative which was easily synthesized in undergraduate laboratory through a solvent-free environmentally friendly method involving controlled heating and agitation. This preparation allowed teaching stereochemistry in undergraduate levels, which entails the synthesis of (S)-pyroglutamic acid and the assessment of its optical purity using the simple and rapid technique of melting point measurement, corroborated by polarimetry. The reasons why the solid-state properties of enantiomeric mixtures can differ from those of enantiopure compounds are also discussed, with optical rotation not being the sole distinguishing property.

Abstract in English:

Sustainability and Sustainable Development Goals (SDGs) have gained prominence in contemporary discourse, driven by the urgency of addressing climate change and demand for transformative actions for planet preservation. Recognized by global entities such as the United Nations and the Brazilian Chemical Society, Basic Education is crucial for instigating societal change. In the context of the diverse Brazilian classrooms, textbooks stand out as a common resource for educators and students, so how would the terms sustainability and SDGs be used in textbooks? Are these terms covered in the context of chemistry? This article utilizes Bardin’s content analysis to approach the terms sustainability and SDGs in National Textbook Program (PNLD) materials for Natural Sciences area, focusing on chemistry. The analysis of PNLD collections revealed that “sustainability” is broadly defined, but lacks specific contextualization within chemistry. SDGs, on the other hand, are mentioned cursorily, serving more as historical markers than engaging in meaningful discourse. Consequently, this article emphasizes the need for greater involvement of the chemistry community in shaping decisions related to textbooks. It calls for a concerted effort by chemistry Educators and Society to actively contribute to educational material discussions, fostering a more comprehensive integration of sustainability and SDGs within Chemistry Education.

Abstract in English:

The interconnectedness between sustainability, sustainable development, sustainable chemistry, and green chemistry is evident in the pursuit of innovative solutions that can balance economic, environmental, and social needs, thereby building a more sustainable future for present and future generations. Although these are topics that have been widely discussed in recent years, there are many controversies regarding the exact definition and scope of these terms. The term “Green Chemistry” was defined with the Twelve Principles of Green Chemistry, but in recent years, aspects of environmental and social costs need to be incorporated into the definition. Historically, green chemistry has tended to focus on the process, i.e., how a product is made, rather than the properties of the product. So, we generally talk about a process being green or not. This contribution aims to discuss the parallels, interconnections and differences that exist among the concepts within the realms of “Sustainability”, “Sustainable Development”, “Sustainable Chemistry”, and “Green Chemistry”. Additionally, it discusses how these topics play a crucial role in mitigating environmental impacts, conserving natural resources, generating employment, and promoting safer and more sustainable products and processes.