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Biochar has been intensively researched worldwide. In Brazil, there is a variety of feedstock production that can be turned into soil amendments of high performance through biochar conversion, especially solid wastes. However, advances in biochar research in Brazil have not been systematically evaluated to indicate possible gaps and suggest future research for eco‐friendly applications. Thus, in this work we evaluated biochar properties and effects on air, water, and soil quality based on data gathered from researches performed in Brazil. Biochar has been mainly evaluated as soil conditioner (37%), material characterization (17%), water treatment (12%), and greenhouse gases emissions (9%). Based on the data synthesis of 68 feedstocks used for biochar production, we observed that the pyrolysis temperature profoundly affects biochar properties. Meta‐analysis indicated benefits of biochar addition to soils for chemical, physical, microbiological and biochemical attributes that have resulted in increases in root growth (+30%), and plant shoots (+45%). Pyrolysis temperature and feedstock are key choices to design biochar properties aiming to retain dyes, aromatic hydrocarbon, pesticides, and metals in water and wastewater treatment. It was also observed an increase in CO2 and a decrease in N2O emissions after biochar application to soils in short‐term experiments. Although there is a growing interest in the development of electrochemical sensors and biochar‐based fertilizers, technological applications of biochar are still incipient in Brazil. Future research should prioritize long‐term and mechanistically evaluations of biochar under field conditions and the development of eco‐friendly technological applications. [ABSTRACT FROM AUTHOR]

Cashew gum (CG) biopolymer is from natural source, biocompatible, non-toxic, inexpensive, and easily extracted from the exudate of the Anacardium occidentale L. tree, which is abundant in the north and northeast of Brazil. Prussian blue nanoparticles (PBNPs) can be embedded in the natural materials and have been used in several (bio)technological applications. This work presents a new cashew gum-based bionanocomposite containing PBNPs prepared in situ (PBNPs@GC), where the CG biopolymer was used as a matrix to prevent nanoparticles aggregation. Herein, investigate the effect of different CG concentrations about the bionanocomposite properties, and demonstrated it use as potential electrochemical sensor for drugs trials. The PBNPs@CG were characterized using UV–Vis, FTIR, XRD, DLS, zeta potential, TEM and cyclic voltammetry. The CG proved to be a suitable host for the PBNPs synthetized. These PBNPs were spherical, crystalline, stable, with a size of 5.0–15.0 nm, and without agglomeration. The bionanocomposite electrochemical behavior shown their ability to the oxidize some drugs, such as metamizole (MTM), acetaminophen (ACT) and methotrexate (MTX). These results demonstrated the innovative character of these bionanocomposite and encourage their further exploration for applications in nanobiomedicine like electrochemical (bio)sensors. Unlabelled Image • Cashew gum coated PBNPs were prepared in situ and characterized. • CG coating decreased the size of the spherical PBNPs from 50 to 5 nm. • CG addition increased the crystallinity of the PBNPs core. • PBNPs@CG showed electroactivity towards dipyrone, acetaminophen and methotrexate. • PBNPs@CG are a potential candidate for applications as electrochemical sensors. [ABSTRACT FROM AUTHOR]

Abstract: The search for bioactive molecules to be employed as recognition elements in biosensors has stimulated researchers to pore over the rich Brazilian biodiversity. In this sense, we introduce the use of natural cashew gum (Anacardium occidentale L.) as an active biomaterial to be used in the form of layer-by-layer films, in conjunction with phthalocyanines, which were tested as electrochemical sensors for dopamine detection. We investigated the effects of chemical composition of cashew gum from two different regions of Brazil (Piauí and Ceará states) on the physico-chemical characteristics of these nanostructures. The morphology of the nanostructures containing cashew gum was studied by atomic force microscopy which indicates that smooth films punctuated by globular features were formed that showed low roughness values. The results indicate that, independent of the origin, cashew gum stands out as an excellent film forming material with potential application in nanobiomedical devices as electrochemical sensors. [Copyright &y& Elsevier]

Abstract: Nowadays, air pollution is a major environmental concern. Phenomena such as global warming, acid rain, depletion of the ozone layer and photochemical smog are directly related to increased anthropic air pollution. At present, the vehicular emission is one of the most important sources of air pollution. The increasing use of automobiles by modern society is leading to an increase of pollutant emissions, thus creating serious problems for the public health in the urban centers. In Brazil, there is a program that encourages large-scale use of Vehicular Natural Gas (VNG). Due to this program, there are over than 1.5 million VNG-powered vehicles in Brazil. This fuel is composed mainly by methane (about 90%) and it is considered to be the fuel that causes less environmental damage, especially if compared with gasoline or diesel oil. However, due to the remarkable increase in the use of VNG powered vehicles in Brazil, it has been necessary to better understand the environmental impacts caused by the burning of this fuel. In this work, electrochemical detectors were used to measure emissions of CO, NOx and SO2, whereas CO2 Laser-based Photo acoustic Spectroscopy was employed to the study of ethylene (C2H4) emitted by VNG-powered vehicles. Measurements were performed in the exhaust of VNG-powered taxis in the state of Rio de Janeiro. We could notice that most of the VNG vehicles emit CO, NOx, SO2 and C2H4 in the ppmV range. This issue varied with the vehicle conditions of maintenance, as well as with its age, engine rotation speed and the origin of the Natural Gas. [Copyright &y& Elsevier]

Hydroxychloroquine (HCQ), a derivative of 4-aminoquinolone, is prescribed as an antimalarial prevention drug and to treat diseases such as rheumatoid arthritis, and systemic lupus erythematosus. Recently, Coronavirus (COVID-19) treatment was authorized by national and international medical organizations by chloroquine and hydroxychloroquine in certain hospitalized patients. However, it is considered as an unproven hypothesis for treating COVID-19 which even itself must be investigated. Consequently, the high risk of natural water contamination due to the large production and utilization of HCQ is a key issue to overcome urgently. In fact, in Brazil, the COVID-19 kit (hydroxychloroquine and/or ivermectin) has been indicated as pre-treatment, and consequently, several people have used these drugs, for longer periods, converting them in emerging water pollutants when these are excreted and released to aquatic environments. For this reason, the development of tools for monitoring HCQ concentration in water and the treatment of polluted effluents is needed to minimize its hazardous effects. Then, in this study, an electrochemical measuring device for its environmental application on HCQ control was developed. A raw cork–graphite electrochemical sensor was prepared and a simple differential pulse voltammetric (DPV) method was used for the quantitative determination of HCQ. Results indicated that the electrochemical device exhibited a clear current response, allowing one to quantify the analyte in the 5–65 µM range. The effectiveness of the electrochemical sensor was tested in different water matrices (in synthetic and real) and lower HCQ concentrations were detected. When comparing electrochemical determinations and spectrophotometric measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of this sensor in different environmental applications. [ABSTRACT FROM AUTHOR]