Navegando por Autor "Vianna, Marilda M. G. R."

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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 site
A comparative study of persulfate activation by iron-modified diatomite and traditional processes for the treatment of 17α-ethinylestradiol in water
(Environmental Technology, 2020-03-05) Chiavone Filho, Osvaldo; Silva, Celyna Káritas Oliveira da; Silva, Silvia S. O.; Souza, Alessandra R.; Aguiar, Leandro G.; Silva, Dannielle J.; Vianna, Marilda M. G. R.; Nascimento, Cláudio Augusto Oller do
Emerging pollutants have been the subject of worldwide study because their continuous entry into the environment presents a risk to ecosystems and human health. Advanced oxidation processes show promise for eliminating or reducing the concentrations of emerging pollutants in water. This study aimed to investigate the treatment of aqueous systems containing the synthetic hormone 17α-ethinylestradiol. An innovative method for persulfate activation catalysed by ironmodified diatomite (heterogeneous system) was compared to conventional homogeneous activation methods (iron activation, alkaline activation, and heat activation). Iron-modified diatomite was more efficient in activating persulfate than traditional processes, achieving 98% of pollutant removal. Experimental results indicated that the catalyst can be reused without loss of removal efficiency, with potential environmental and economic benefits
Remediation of phenanthrene-contaminated soil by persulfate activated with Fe-Modified diatomite: kinetic and statistical approaches
(Springer Nature, 2017-07-10) Chiavone Filho, Osvaldo; Rackov, Celyna Káritas Oliveira da; Aguiar, Leandro G.; Souza, Alessandra R.; Silva, Silvia S. O.; Câmara, Alan G.; Vianna, Marilda M. G. R.; Foletto, Edson Luiz; Nascimento, Cláudio Augusto Oller do
An innovative diatomite-supported iron catalyst has been developed by using an impregnation process with a mixture of ferrous (Fe2+) and ferric (Fe3+) ions in the form of precipitated iron hydroxides. Raw and modified diatomite samples have been characterized by X-ray fluorescence and scanning electron microscopy. The main characterization results have revealed that modified diatomites are amorphous and have higher iron concentrations than raw diatomite. The results also indicate that the modified materials provided significant catalytic activity on phenanthrene degradation by using sodium persulfate. Satisfactory results were obtained with 45 g/L of sodium persulfate and 1 g of modified diatomite, thus degrading 98% of phenanthrene during 168 h of treatment. Kinetic and statistical approaches were developed for the remediation process herein, which have been validated with experimental data, thence yielding suitable results
Remediation of solid matrix containing anthracene and phenanthrene by permanganate oxidant
(Global NEST, 2014-04-08) Silva, C. K. O.; Aguiar, L. G.; Ciriaco, M. F.; Vianna, Marilda M. G. R.; Nascimento, Cláudio Augusto Oller do; Chiavone Filho, Osvaldo; Courtial, Camila Gambini Pereira; Foletto, Edson Luiz
This paper reports on a systematic study of the degradation of anthracene and phenanthrene in sandy soil treated with an aqueous solution of KMnO4. A kinetic model was developed based on the soil/solution ratio to predict the degradation rates of anthracene and phenanthrene. The degradation profiles achieved with the best dosage were also determined. The proposed model provided a reasonable prediction of acceptable residual contaminant concentrations. The oxidation efficiency was found to be higher than the value provided by the treatment in which the reduction of KMnO4 to MnO2 is considered to be the only reduction mechanism

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Navegando por Autor "Vianna, Marilda M. G. R."