Diesel removal in non-aqueous phase by fibres from Calotropis procera: kinetic, isothermal and sorption potential evaluation.

Calotropis procera fibres have been proposed for free-phase diesel removal in case of spillage into groundwater. For this, characterizations were carried out using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FEG-SEM), wettability and contact angle measurements. Sorption oil capacity, kinetic, isothermal and recycling behaviour were evaluated. For initial optimization of the oil sorption capacity, an experimental design (DOE) was applied, with the optimized condition being 60 g L-1 of diesel in water and 0.01 g of fibre. Then, the results clearly indicated that the fibres have a hydrophobic and oleophilic character, quickly reaching more than 71.43 g g-1 of diesel sorption, according to the adjustment (R² > 0.99) of the pseudo-second order and Langmuir models, governed by absorption mechanisms. It should also be noted that at the end of 8 reuse cycles, the fibre presented a total accumulated sorption capacity of about 252.6 g g-1 of diesel. Furthermore, a laboratory-scale experiment was carried out to remove diesel from groundwater in gas station areas, the fibre removed 98.55% to 99.97% of removal efficiencies were achieved of the free phase over time. Therefore, the material demonstrates excellent characteristics for removing diesel spills in groundwater due to its fast, high and stable removal capacity.

Marine Submicron Aerosols from the Gulf of Mexico: Polluted and Acidic with Rapid Production of Sulfate and Organosulfates.

We measured submicron aerosols (PM1) at a beachfront site in Texas in Spring 2021 to characterize the "background" aerosol chemical composition advecting into Texas and the factors controlling this composition. Observations show that marine "background" aerosols from the Gulf of Mexico were highly processed and acidic; sulfate was the most abundant component (on average 57% of total PM1 mass), followed by organic material (26%). These chemical characteristics are similar to those observed at other marine locations globally. However, Gulf "background" aerosols were much more polluted; the average non-refractory (NR-) PM1 mass concentration was 3-70 times higher than that observed in other clean marine atmospheres. Anthropogenic shipping emissions over the Gulf of Mexico explain 78.3% of the total measured "background" sulfate in the Gulf air. We frequently observed haze pollution in the air mass from the Gulf, with significantly elevated concentrations of sulfate, organosulfates, and secondary organic aerosol associated with sulfuric acid. Analysis suggests that aqueous oxidation of shipping emissions over the Gulf of Mexico by peroxides in the particles might potentially be an important pathway for the rapid production of acidic sulfate and organosulfates during the haze episodes under acidic conditions.

Comprehensive two-dimensional liquid chromatography-based quali-quantitative screening of aqueous phases from pyrolysis bio-oils.

Pyrolysis processes are an alternative to minimize the environmental problem associated to agrifood industrial wastes. The main product resulting from these processes is a high-value liquid product, called bio-oil. Recently, the use of comprehensive two-dimensional liquid chromatography (LC × LC) has been demonstrated as a useful tool to improve the characterization of the water-soluble phases of bio-oils, considering their complexity and high water content. However, the precise composition of bio-oils from different agrifood byproducts is still unknown. In the present study, the qualitative and quantitative screening of eight aqueous phases from different biomasses, not yet reported in the literature, using LC × LC is presented. The two-dimensional approach was based on the use of two reverse phase separations. An amide column in the first dimension together with a C18 column in the second dimension were employed. Thanks to the use of diode array and mass spectrometry detection, 28 compounds were identified and quantified in the aqueous phase samples with good figures of merit. Samples showed a distinct quali-quantitative composition and a great predominance of compounds belonging to aldehydes, ketones and phenols, most of them with high polarity.

Aplicação de métodos geofísicos no monitoramento de área contaminada sob atenuação natural / Applications of geophysical methods in monitoring contaminated area under natural attenuation

Estudos geofísicos em áreas impactadas por derivados de petróleo descrevem anomalias tanto de baixa quanto de elevada resistividade, confirmada como fase contaminante por meio de análises químicas. Esta aparente contradição pode refletir processos de degradação, associada ao tempo de residência de contaminantes no meio, por meio da geração de subprodutos que alteram as propriedades físicas do meio, principalmente pela dissolução mineral por ação de ácidos orgânicos e pela neoformação de minerais de óxidos e hidróxidos de ferro. Este trabalho apresenta resultados da aplicação do método de eletrorresistividade e polarização induzida em uma área industrial contaminada por benzeno, tolueno, xileno, 1,2 dicloroetano e sais inorgânicos, em processo de atenuação natural. Os resultados indicam a neoformação mineral no centro e nas adjacências da área contaminada, conforme sugerem as alterações apontadas nos parâmetros físicos medidos.

Geophysical studies in impacted areas by petroleum products may be described by anomalies of both low and high resistivity, confirmed as contaminant by chemical analyses. This apparent contradiction can reflect processes of contaminants degradation, directly associated with its residence time in the soil, through the generation of by-products that change the physical properties of the soil and groundwater, principally for the mineral dissolution by action of organic acids and by neoformation minerals of oxides and hydroxides minerals. This paper presents the application of electrical resistivity and induced polarization methods in a contaminated industrial area for benzene, toluene, xylene, 1,2 dichloroethene and inorganic salts, in natural attenuation process. The results indicated the mineral neoformation in the center and adjacencies of contaminated area, as it suggested the alterations in physical parameters measured.

Película lagrimal: estructura y funciones / Tear film, structure and function

Un vestigio de la evolución de las formas de vida acuática a la vida terrestre es el sistema lagrimal y su función principal es prevenir la sequedad del segmento anterior del ojo para permitir su funcionamientoen el medio ambiente terrestre. El producto de este sistema es la lágrima y ya en el siglo V a.C., Hipócrates reconocía su importancia. Esta fina películaes muy versátil y tiene gran capacidad de adaptacióna los cambios del entorno; sin embargo, cuandolas condiciones son muy adversas, puede tornarse frágil y reducir su funcionalidad exponiendo al ojo a daños potenciales. La comprensión de la estructura de la película lagrimal es necesaria para diferenciar su funcionamiento normal del anómalo, lo que conllevaríaa un diagnóstico más acertado de las alteracioneslagrimales. Se detallarán las partes correspondientesa los meniscos marginales de los párpados y la película lagrimal propiamente dicha, dada su importanciaen la integridad corneal y ocular. El objetivode esta revisión temática es describir diferentes teorías propuestas sobre la estructura y funciones de la película lagrimal, como base fundamental para el entendimiento de su desempeño clínico.

A vestige of the evolving forms of aquatic life to terrestrial life is the lacrimal system and its main function is to prevent dryness of the anterior segment of the eye to allow their operation in the Earth’s environment. The product of this system is already in tears and the 5th century BC, Hippocrates recognized its importance. This thin film is very versatile and has great ability to adapt to the changing environment, but when conditions are adverse, it may become fragile and reduce its functionality exposing the eye to potential damage. Understanding the structure of the tear film is necessary to differentiate its normal operation of the anomalous, which would lead to a more accurate diagnosis of the lacrimal alterations. It detailed the parties for the meniscus fringe of the eyelids and tear film itself, given its importance in the integrity and corneal eye. The objective of this thematic review is to describe different theories proposals on the structure and functions of the tear film, as the foundation for the understanding of their clinical performance.

Calculation of fermentation parameters from the results of a fed-batch test taking account of the volume of biomass in the fermenting medium

The volume of biomass in the fermenting medium may significantly affect the values of fermentation parameters calculated from the measured concentrations of the substrates and/or products. The corrections proposed in this paper should be evaluated and, depending on their magnitude, considered in order to obtain more representative results. A numerical example is presented.

O volume da biomassa no meio em fermentação pode afetar significativamente os parâmetros do processo calculados a partir das medidas das concentrações de substratos e/ou produtos. Correções propostas neste trabalho deveriam ser avaliadas e, dependendo de seus valores, consideradas a fim de obter resultados mais representativos. Apresenta-se um exemplo numérico.