RESUMO
CO2 capture and storage in geological reservoirs have the potential to significantly mitigate the effects of anthropogenic gas emissions on global climate. Here, we report the results of the first laboratory experiments of CO2 injection in continental flood basalts of South America. The results show that the analyzed basalts have a mineral assemblage, texture and composition that efficiently allows a fast carbonate precipitation that starts 72 h after injection. Based on the availability of calcium, chemical monitoring indicates an estimated CO2 storage of ~ 75%. The carbonate precipitation led to the precipitation of aragonite (75.9%), dolomite (19.6%), and calcite (4.6%).
RESUMO
In this work the urban area of Aracaju city, located in the State of Sergipe, Northeastern Brazil was the site for simultaneous collection of suspended particles (TSP) and inhalable particulate matter (PM10) aiming an evaluation of the air quality parameters. Concentrations of Cd, Co, Cu, Fe, Mn, Ni, Pb and V in TSP and PM10 were determined by inductively coupled plasma mass spectrometry (ICP-MS). Iron was the most abundant element found in both particulate samples. Through chemometric tools, it was possible to point out that the contributions to the TSP and PM10 formation are similar, and strong correlations were observed between Fe-Mn (0.83) and Cd-Pb (0.93) in TSP, and Fe-Mn (0.90), Fe-Cu (0.81) and Cd-Pb (0.97) in PM10, an evidence that these species are from sources related mainly to soil resuspension and vehicular traffic. Enrichment factor (EF) and geoaccumulation index (Igeo) showed an influence of fossil fuel burning in the composition of TSP and PM10. Through principal component analysis (PCA) and hierarchical cluster analysis (HCA) it was observed particle size distribution groupings according to its aerodynamic size. Evaluation of the concentrations obtained for the collected samples according to the seasons (dry and rainy), indicated the influence of both, biogenic (resuspension of soil and marine aerosols) and anthropic (vehicle traffic and biomass burning) sources.
Assuntos
Poluentes Atmosféricos , Oligoelementos , Brasil , Cidades , Monitoramento Ambiental , Tamanho da Partícula , Material ParticuladoRESUMO
In this work, fast sequential determination and chemical speciation analysis of inorganic arsenic and antimony in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by hydride generation atomic absorption spectrometry (HG-AAS) is proposed. A Doehlert design was applied to optimise the hydride generation conditions of As and Sb for fast sequential determination in the same aliquot of particulate matter samples after preparation of the slurry. The limits of quantification (LoQ) obtained for As and Sb were 0.3 and 0.9 ng m-3, respectively. The accuracy of the analytical method was confirmed by analysis of the certified reference material of urban particulate matter (SRM NIST 1648a), presenting concordance with certified values of 92.7±7.7% for As and 91.2±9.5% for Sb. Precision was expressed as relative standard deviation (% RSD, n=3), with our results presenting values better than 3.4% and 4.2% for total inorganic As and Sb, respectively. For all analysed samples, total As concentrations and its inorganic species were below the LoQ of the analytical method (<0.3 ng m-3). However, the averages of total inorganic Sb concentrations in airborne particulate matter, collected as total suspended outdoor particles (TSPoutdoor), inhalable particulate matter (PM10), and total suspended indoor particles (TSPindoor), were 3.1±0.5, 2.4±0.6, and 2.6±0.4 ng m-3, respectively. Trivalent Sb (Sb3+) was the predominant inorganic species in all samples investigated, with mean percentages of 76%, 72%, and 73% in TSPoutdoor, PM10, and TSPindoor, respectively. The presence of Sb and its predominant inorganic form (Sb3+) can be attributed to vehicular traffic close to the sampled urban areas. Therefore, fast sequential determination of As and Sb and their inorganic species in particulate matter samples prepared as slurry by FS-HG-AAS is an efficient, accurate, and precise method and can be successfully applied to routine analysis.