RESUMO

In the last few years, the presence of geosmin (GEO) in water bodies has caused serious problems related to water consumption by the population. Many studies focus on its occurrence and detection, but little is discussed about the technologies for treatment and removal of this contaminant. In this way, the present work aims to present a bibliographic search and a bibliometric analysis carried out in the Web of Science database and in VOSviewer software about geosmin remediation, in the last 10 years. 100 articles were found, of which only one, from 2021, was a review. It was possible to assess that the subject has gained greater notoriety in the last 7 years, since the year 2016 marked the increase of publications on the subject, as well as an increasing number of citations. Among the most published countries is the People's Republic of China, with 53% of publications. Bibliometric analysis showed that GEO is directly related to 2-methylisoborneol (2-MIB), since both occur simultaneously in water bodies. In addition, it was possible to identify that adsorptive processes are the most used in the removal of these contaminants, followed by advanced oxidative processes and biological processes, in that order.

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RESUMO

The incorporation of drugs in nanocomposites can be considered a potential strategy for controlled drug release. In this study, a nanocomposite based on bacterial cellulose and the palygorskite clay (BC/PLG) was produced and loaded with metronidazole (MTZ). The samples were characterized using X-ray diffraction (XRD) Spectroscopy, thermal analysis (TG/DTG) and Scanning Electron Microscopy (SEM). The barrier properties were determined to water vapor permeability (WVP). Adsorption tests with PLG were performed using MTZ and drug release profile of the membranes was investigated. The results indicated that PLG increased the crystallinity of the nanocomposites, and greater thermal stability when PLG concentration was 15.0% (BC/PLG15) was observed. WVP of the samples also varied, according to the clay content. Adsorption equilibrium was achieved from 400 mg/L of the PLG and a plateau in the MTZ release rates from BC/PLG was observed after 30 min. Therefore, the results of this study show the potential of these nanocomposite membranes as a platform for controlled drug release.

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RESUMO

RESUMO Áreas contaminadas por metais podem configurar sério risco à saúde pública e ao meio ambiente. Na década de 1980 foi instalado um pátio de estocagem provisória de resíduos industriais perigosos (CENTRES), no município de Queimados, Rio de Janeiro, o que causou um grande impacto ambiental ao solo da região. A legislação brasileira para o diagnóstico de áreas contaminadas limita a extração de metais em solos aos métodos recomendados pela United States Environmental Protection Agency (USEPA) 3050 e 3051A. Entretanto, muitos pesquisadores utilizam o método com água-régia para a extração de metais em solo, mas são escassos estudos que comparem as concentrações de metais extraídos por água-régia e USEPA 3051A. Logo, o objetivo deste trabalho foi avaliar se o método de extração de metais em solos por água-régia é estatisticamente diferente do método USEPA 3051A. Os resultados obtidos revelaram que as concentrações de Cd, Cr, Cu, Ni, Pb e Zn utilizando ambas as extrações (água-régia e USEPA 3051A) foram estatisticamente semelhantes. Também foi possível identificar que as concentrações de Cu, Ni, Pb e Zn foram superiores ao valor de investigação industrial, o que caracteriza essa área como altamente contaminada e solo classe 4.

ABSTRACT Metal contaminated areas lead to environmental and public health risks. In the 1980s, dangerous industrial waste storage was initiated in the CENTRES area in the municipality of Queimados, Rio de Janeiro, Brazil. The inadequate management of these wastes has promoted a large environmental impact to this region's soils. The Brazilian legislation for diagnostics of contaminated areas limits the extraction of metals on soils to USEPA 3050-B and USEPA 3051-A methods. However, many researchers use the aqua regia method for extracting metals in soil, but there are few studies comparing concentrations of metals extracted by aqua regia and USEPA 3051A. Therefore, the objective of this work was to evaluate if the method of extracting metals in soils by aqua regia is statistically different from US EPA 3051A. The results showed that the Cd, Cr, Cu, Ni, Pb and Zn concentrations using both extractions were statistically similar. It was also observed that Cu, Ni, Pb and Zn concentrations were higher than the industrial investigation value which characterizes this area as highly contaminated and soil class 4.