Resumo em Inglês:

Ozone (O3) is a secondary pollutant, and modeling studies used to assess its behavior play a role in facilitating regulatory and decision-making processes in public policies. Thus, the Community Multiscale Air Quality (CMAQ), a chemical transport model, was specifically designed to simulate and forecast O3 concentrations. This critical review includes publications between 2016 and 2023 showing the most used configurations. The research was carried out in the Scopus and Web of Science databases, and the articles were filtered using determined criteria. With this, it was observed that the most used model arrangements are Weather Research and Forecasting as a meteorological model, carbon bond 2005 as the chemical mechanism, 36 × 36 km with 35 vertical layers as grid resolution, CMAQ standard profiles as a boundary condition, Multi-resolution Emission Inventory for China, due to the high number of publications by Chinese researchers, and Model of Emissions of Gases and Aerosols from Nature as inventory and processor of biogenic emissions, respectively. It is concluded that this arrangement of configurations is the most widespread in the literature but shows that nowadays the publications predominantly lie over China and with greater prominence of this country in studies of influence on ozone simulation.

Resumo em Inglês:

This study aimed to establish the longitudinal gradient and historical trends of arsenic and metals in a tropical reservoir. Water and sediment samples were collected along the Rio Bonito reservoir (Espírito Santo, Brazil), and a sediment core was obtained from the lacustrine zone. Plasma spectrometric techniques were employed to determine concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, and Pb in water and sediment samples, and the sediment samples were dated using high-resolution gamma spectrometry. Higher concentrations of elements were observed in surface water samples from the riverine zone and bottom water samples from the transition zone. Concerning surface sediment samples, elevated concentrations were noted in the transition and lacustrine zones, where deposition is more intense. The sediment core was dated to 1940, before the reservoir dam construction, utilizing 210Pb dating. Certain elements exhibited progressively increasing concentrations over time. Enrichment factor, pollution load, and ecological risk indexes indicated the need for continuous monitoring of this reservoir.

Resumo em Inglês:

Nanocomposites of magnetite anchored on reduced graphene oxide with different magnetite:reduced graphene oxide mass ratios were synthesized and evaluated in indigo carmine photo Fenton discoloration. All nanocomposites are magnetic and showed comparable amounts of magnetite and hematite with a higher level of hematite for low iron contents. The highest value of 63.6 emu g−1 was obtained for the nanocomposite with the highest magnetite content. The nanocomposites presented high dispersion of iron oxide particles, at about 12 nm on reduced graphene oxide surface sheets. The samples also showed bandgap energies below that found for bulk magnetite, showing an important effect of reduced graphene oxide. The nanocomposite with an iron nitrate precursors mass ratio of 17:1 showed the best performance (99.7% of indigo carmine discoloration (2.1 × 10−5 mol L−1) at 30 min of reaction, hydrogen peroxide (2.3 × 10−1 mol L−1), and a catalyst dosage of 0.67 g L−1). Reusability tests were performed, and this nanocomposite was shown to be active for at least three recycles. X-ray photoelectron spectrum of Fe2p3/2 showed that the FeIII/FeII ratio was maintained even after three recycles (4 runs), meaning that reduced graphene oxide is responsible for stabilizing magnetite particles, thus maintaining its photocatalytic activity.

Resumo em Inglês:

Natural waters from the Paraná River hydrographic basin in the Brazil-Paraguay cross-border region were analyzed by liquid chromatography coupled to a fluorescence detector (LC-FLD) after extraction of the analytes in anion exchange resin IRA-900. The method allowed good recovery (91 to 113%) of the studied species (glyphosate, (aminomethyl)phosphonic acid (AMPA) and glufosinate) precision compatible with the requirements of the National Metrology Institute (relative standard deviation < 18%) and limit of quantification (LOQ) values between 0.2 and 0.8 μg L−1. In most of the samples collected between January and September 2022, it was impossible to detect the presence of herbicides, even in regions of intense agricultural activity, probably due to the high adsorption capacity of the soils of the region and due to the higher LOQ of the method. Under these conditions, the main transport route is estimated to be associated with surface runoff, which is only favored by heavy rainfall events.

Resumo em Inglês:

A new composite material with magnetic and pH-responsive properties, composed of chitosan/poly(2-diisopropylamino)ethyl methacrylate (Fe3O4/SiO2/CS/PDPA) was developed with the purpose of removing avermectins in aqueous media. The material was characterized by different techniques to evaluate its characteristics. The adsorption process was investigated through the optimization of some parameters, with the most favorable results at pH 8.0, using 20 mg of adsorbent and stirring for 5 min. Under such conditions, the material showed adsorption efficiency of around 80.5, 69.9, and 74.8% for eprinomectin, doramectin and ivermectin, respectively. The adsorption mechanism was investigated using the pseudo-second order kinetic model and the Langmuir-Freundlich dual site isotherm model. Thermodynamic analysis indicated that the adsorption process is exothermic and spontaneous. The material also showed good regenerative capacity, allowing several reuse cycles. The results obtained suggest that the synthesized material has potential application as an adsorbent in the removal of avermectins from aqueous samples.

Resumo em Inglês:

Hydrogel films based on gelatin, glutaraldehyde and glycerol are widely reported in many studies with applications focused on food packaging, microencapsulation and release of active drugs. Thus, this study used this composition to produce hydrogel films and brought as a novelty the incorporation of tannic acid (TA) as anti-aging active, due to its great antioxidant capacity. The presence of TA in the hydrogel films was verified by the C–O stretch absorption band at 1020 cm-1, as well as by its thermal degradation between 200 and 300 ºC. Furthermore, the presence of this active compound, which influenced the physical, morphological and mechanical properties of the film, was also confirmed by qualitative release tests. Additionally, the mechanical properties of the HT2 hydrogel film showed acceptable values of elongation at break (28.9 ± 3.1%) and Young modulus (6.4 ± 1.1 MPa), suggesting that this film has the potential to be applied in skin care routines.

Resumo em Inglês:

Thiophosphonates, a class of the organophosphate compounds, are of pharmaceutical and agricultural significance. Albeit their broad scope for peaceful uses, they may also be precursors and markers to toxic chemicals, such as the nerve agent VX and other V-series agents, leading to their inclusion into the Annex on Chemicals of the Chemical Weapons Convention (CWC). Considering that they are related to chemical warfare agents and the position of our laboratory as an Organization for the Prohibition of Chemical Weapons (OPCW) Designated Laboratory for analysis of authentic environmental samples, this study aims to contribute to the understanding of the synthesis of thiophosphonates through O,O ’-diethyl methylphosphonate conversion to O,O ’-diethyl methylphosphonothioate using Lawesson’s reagent, exploring different conditions previously reported by the literature, in order to further build a compound library for CWC verification purposes. Synthesis of the compounds has been carried out in sealed, pressure tubes, adding novelty to the present study. Reactions were followed by gas chromatography and 31P nuclear magnetic resonance, and principal component analysis was employed to understand the intricate factors influencing thiophosphonate synthesis yield as duration, temperature and solvent. The research aims to reinforce or challenge existing scientific knowledge, providing insights into parameters related to phosphonate thionation using Lawesson’s reagent, contributing to a deeper understanding of this chemical reaction.