Resumo em Inglês:

The simultaneous diffusion of inorganic components in the olive pulp in wet brine was modeled based on Fick’s generalized 2nd Law and simulated using the finite element method. The main and crossed diffusion coefficients, the film coefficient and the Biot number were determined, with the application of the simplex optimization method, through the minimization of the percentage errors. The errors between the simulated and experimental data were 5.35% for NaCl and 4.77% for KCl and the adjusted main diffusion coefficients were 0.4358 × 10-12 m2 s-1 for NaCl and 0.5408 × 10-12 m2 s-1 for KCl. The system developed to simulate diffusion allows the control and modulation of the salts content that diffuses through the olive pulp.

Resumo em Inglês:

Tetracyclines comprise a large group of broad-spectrum antibiotics used in human and veterinary medicine. Its mechanism of action, via oral ingestion, is to inhibit bacterial protein synthesis, but a large amount (70%) is eliminated without being metabolized, which presents a risk for the arising of antibiotic-resistant species. In this study, the degradation of Tetracycline TC by non-thermal plasma NTP and the antimicrobial sensitivity of the treated solution are investigated. The degradation was followed by chromatographic analysis while the efficiency of NTP in inhibiting the action of TC on bacteria was evaluated by antimicrobial sensitivity test by disk diffusion method. The results showed a high rate of TC degradation, over 90%, in 10 min of NTP treatment for a 60 mL (107 mg L-1) sample and very slow increase up to 94% in 30 min. The antimicrobial sensitivity test of TC after degradation by NTP showed no antibiotic activity. Therefore, our findings are encouraging, since the removal efficiency is below the minimum threshold require, to prevent with high probability, outgrowth of antibiotic-resistant bacteria. In addition, the results confirm that the NTP treated solution is safe to the environment.

Resumo em Português:

Metallurgical waste and vermiculite are solid residues that have potential of utilization as filtering material. Nevertheless, they are commonly discarded. These materials have chemical sites like Si-O, Si-O-Si in vermiculite or have good ionic exchange properties like iron oxide compounds that can be used in adsorption processes. When these materials are combined with a synthetic blanket (OH, C=C, CO and C-H groups), it composes a filter layer with potential to be used in wastewater treatment. In this article, these materials were chemically treated and characterized by Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and coupled TG-FTIR. The results suggest that organic compound contamination was not found after chemical treatment, which could have remained over the unity operations in the Metallurgical processes. The thermal and acid treatments influenced a major formation of iron oxide formation, but its oxidation degree (FeO, Fe2O3, or Fe2O3.FeO) were dependent on the sample granulometry. The Vermiculite shows an irreversible chemical modification after thermal treatment. The characterization of these residues shows its potential use as material in filter construction. Hence, it is fundamental to minimize the environmental impacts as well as to diminish the production costs in wastewater treatment.

Resumo em Inglês:

Curcumin, a phytochemical, exhibits several biological properties and has been studied for the treatment of psoriasis. To facilitate its transdermal permeation, permeation enhancers such as choline and geranic acid ionic liquid (CAGE-IL) have been studied. From this perspective, the research effort entertained herein aimed at developing and evaluating the stability of an emulsion prepared with curcumin (phytochemical from Curcuma longa L.) and locust bean gum (extracted from the seeds of the carob tree, Ceratonia siliqua), with CAGE-IL as a facilitator of transdermal permeation. Stability studies were carried out for six months, with analyses being performed at time intervals of 0 (24 h), 30, 60, 90, and 180 days. The samples were kept at 40 ± 2 °C, with 75 ± 5% relative humidity (RH). The parameters analyzed were morphological characteristics, pH (5.8-6.0), and spreadability. The samples were shown to be stable during the timeframe studied, maintaining adequate physicochemical characteristics and meeting quality specifications for cutaneous applications. CAGE-IL, in addition to facilitating permeation of the active substance, also favored the formation of a stable emulsion encompassing nanosized particles (134.3 ± 2.6 nm) in a simple fashion and with only a few components.

Resumo em Inglês:

This work presented a new PEG modified calix[4]arene stationary phase (C4A-PEG-2PTSC) for gas chromatographic (GC) separations. The statically coated C4A-PEG-2PTSC column exhibited moderate polarity and column efficiency of 2224 plates m-1 determined by 1-octanol at 120 oC. The results showed that the C4A-PEG-2PTSC column exhibited the good separation performance for various types of analytes containing halogenated benzenes, benzaldehydes, phenols, alcohols, anilines isomers and showed the different retention behavior with the comparative columns. Importantly, it showed the better separation capacity of toluidine and xylidine isomers than commercial HP-35 column. Moreover, it was applied in practical sample analysis to detect the content of isomer impurities. This work exhibited the good application potential of C4A-PEG-2PTSC stationary phase in GC analyses.

Resumo em Inglês:

In recent years, the safety of sunscreens to coral reefs and the role these products would play in the process of coral bleaching has been a concern. However, the discussion centers almost exclusively on the organic components used as UV filters, with little attention given to inorganic UV filters, such as zinc oxide. Zinc oxide nanoparticles (ZnO-NPs) have been a common ingredient of sunscreen formulations for decades and are being discharged in coral reef environments. Even though there are data supporting that ZnO is toxic to certain species of fish and algae, regulatory agencies do not appear concerned with the possible outcome of the exposure of corals and their algal symbionts to this metal oxide. This review compiles the published work on the toxicity of ZnO and ZnO-NPs to corals and zooxanthellae, which strongly supports the notion that zinc oxide is toxic to both corals and microalgae. In view of this, concern has been raised by the use of the “reef safe” label to promote sunscreens that lack specific organic components, however containing ZnO as the major UV filter.

Resumo em Inglês:

In this work, the effects of electric pulse treatment on the discharge and electrochemical properties of rolled and extruded AZ61 as anode of Mg-air battery were studied. The microstructure, electrochemical behavior and surface morphology after discharge were discussed to relate the discharge performance. The experimental results show that compared with the original magnesium anode (rolled and extruded), the magnesium anode treated by electric pulse has more negative corrosion potential, lower impedance value, higher discharge voltage and better specific energy. This is because electric pulse treatment can cause the coarse second phase in magnesium anode to dissolve and the grains to become more uniform. In particular, in the discharge process, the surface of magnesium anode after electric pulse treatment will form micro cracks, which is beneficial to promote the self-stripping of discharge products. It is worth noting that the effect of electric pulse treatment on rolled anode is better than that of extruded anode. It may be due to the different dislocation density in the two anodes. During the electric pulse treatment, the dislocation density in the alloy is highly correlated with the dissolution rate of β-Mg17Al12, which ultimately affects the volume fraction of the second phase in the alloy.

Resumo em Português:

Medicinal products based on the Cannabis sativa plant are available in Brazil, among them, drug, cannabis products, individual import products, and those provided by patient associations. Despite this, there is no monograph for the evaluation of cannabinoids in Brazilian Pharmacopoeia (BP) or other compendia accepted. Therefore, this work aimed to develop a quick and easy method to quantify cannabinoids in authorized products for medicinal purposes. The method was developed by HPLC-UV, gradient elution composed of formic acid in acetonitrile and water, the flow rate of 0.6 mL min-1 and 220 nm detection. It was possible to resolve the peaks of cannabidiol (CBD), tetrahydrocannabinol (THC), cannabidiolic acid and cannabinol and to quantify CBD (105.35%; 104.07%) and THC (106.62%). The developed method was applied to two products and met the established requirements of precision, accuracy, linearity, and selectivity. This procedure has been tested on four cannabis-based products to attest to its effectiveness. Considering the importance of establishing minimum quality requirements for medicinal products and considering the available products in Brazil, it was found that it is important to evaluate the implementation of other products in the method developed for future validation and later inclusion in the BP.

Resumo em Português:

This work investigated Brazilian academic production about reading in chemistry classes published in journals of research in science education. To this end, a literature review was conducted from sixteen journals between 2010 and 2021. Two main aspects were analyzed: indicators of production (papers per year and per journals, education level, geographic region and institutions of the study) and the purposes of the activities of reading. In terms of the indicators of production, the results pointed out a consistent interest on this issue in the last decade with papers published in diverse journals, regional predominance from the Southeast and concentration of publications in high school or university levels. Regarding the purposes of reading, three main categories were identified: reading for information, reading for the development of skills and reading for scientific communication. Besides, different genre of texts has been employed in reading practices. Among the challenges are the reduction of regional asymmetries, the addressing of studies for other levels of education, as well as the increasing of research and systematic practices of reading based on a critical point of view.

Resumo em Português:

The Italian chemist Primo Levi (1919-1987) published a testimonial literature about the period he was captive in Auschwitz, later exploring other literary genres. In his work as a whole, the science-art relationship takes place both in terms of content (when chemistry and scientific knowledge are themes) and form (when the author appropriates the language and logic of science to communicate his experiences, especially those lived in the concentration camp). Three themes related to the chemical universe are present in Levi’s writings: experiments, man’s relationship with matter and chemistry as a work. In this article, we bring these topics closer to current discussions in the field of philosophy of chemistry. The philosophical discussion and Primo Levi’s literature converge on the understanding that experiments assumes a particular role in chemistry, that matter is a central category for this science and that the chemical profession raises ethical questions, such as those related to impacts of the incessant production of new substances.