Navegando por Autor "Soares, Lélia C. R."
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Artigo Characterization and partitioning behavior of creosote in different matrices: soil, water, and air(Water, Air, and Soil Pollution, 2020-07-24) Chiavone Filho, Osvaldo; Aranha, Rayanne Macêdo; Magalhães, Vivian Maria de Arruda; Mendes, Gabriela Paupitz; Soares, Lélia C. R.; Barbosa, Alexandre Muselli; Nascimento, Cláudio Augusto Oller do; Vianna, Marilda M. G. R.Creosote is a multicomponent oil classified as a dense non-aqueous phase liquid (DNAPL) produced from coal tar distillation. The concept of phase distribution is critical in decision-making to remediate contaminated sites. The creosote mass transfer between sorbed, aqueous, vapor, and DNAPL phases is controlled by physicochemical characteristics, geology of the site, and environment conditions. This study evaluated phase distribution of the main polycyclic aromatic hydrocarbons (PAHs) of creosote in a sandy soil with low organic matter content. The creosote was collected from a contaminated site in São Paulo, Brazil, and was characterized by gas chromatography–mass spectrometry (GC-MS). Clean soil was collected upgradient from the same area. Initially, the soil was artificially contaminated with creosote. After, the contaminated soil was put in contact with clean water in sealed vials for 72 h. Samples of the soil, vapor, and liquid phases were collected and analyzed by GC-MS. In total, 50 compounds were identified in the creosote, and 9 PAHs were selected to be studied, which represented around 30% of total creosote mass. The major contaminant concentration was detected in the sorbed phase. For instance, naphthalene mass was distributed in sorbed (33.0%), DNAPL (1.5%), aqueous (3.4%), and vapor (0.2%) phases. The results provided an understanding of the contaminant species partitioning that occurs in a real contaminated siteArtigo Treatability studies of naphthalene in soil, water and air with persulfate activated by iron(II)(Elsevier, 2020-04) Chiavone Filho, Osvaldo; Mendes, Gabriela Paupitz; Magalhães, Vivian M. A.; Soares, Lélia C. R.; Aranha, Rayanne Macêdo; Nascimento, Cláudio Augusto Oller do; Vianna, Marilda M. G. RamosChemical oxidation was applied to an artificially contaminated soil with naphthalene (NAP). Evaluation of NAP distribution and mass reduction in soil, water and air phases was carried out through mass balance. Evaluation of NAP distribution and mass reduction in soil, water and air phases was carried out through mass balance. The importance of the air phase analysis was emphasized by demonstrating how NAP behaves in a sealed system over a 4 hr reaction period. Design of Experiments method was applied to the following variables: sodium persulfate concentration [SP], ferrous sulfate concentration [FeSO4], and pH. The system operated with a prefixed solid to liquid ratio of 1:2. The following conditions resulted in optimum NAP removal [SP] 1⁄4 18.37 g/L, [FeSO4] 1⁄4 4.25 g/L and pH 1⁄4 3.00. At the end of the 4 hr reaction, 62% of NAP was degraded. In the soil phase, the chemical oxidation reduced the NAP concentration thus achieving levels which comply with Brazilian and USA environmental legislations. Besides the NAP partitioning view, the monitoring of each phase allowed the variabilities assessment over the process, refining the knowledge of mass reduction. Based on NAP distribution in the system, this study demonstrates the importance of evaluating the presence of semi-volatile and volatile organic compounds in the air phase during remediation, so that there is greater control of the system as to the distribution and presence of the contaminant in the environment. The results highlight the importance of treating the contaminant in all its phases at the contaminated site