Transferência do radônio em soluções portadoras de derivados de petróleo
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Data
2024-03-21
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Universidade Estadual Paulista (Unesp)
Resumo
Experimentos conduzidos em laboratório na escala de tempo de cerca de 25 a 210 dias foram realizados para avaliar a transferência de radônio de diferentes minerais (tantalita, cassiterita e columbita) para soluções consistindo de água destilada e os seguintes derivados de petróleo: gasolina misturada com álcool anidro (27%), gasolina utilizada na aviação, óleo diesel e querosene. A concentração de urânio nos minerais variou de 421 a 1700 ppm, tendo sido também realizados ensaios empregando soluções contendo nitrato de uranila dissolvido e padrão de rádio-226 com valor conhecido de atividade (2 nCi = 74 Bq). Foi realizado um total de 61 leituras da concentração de atividade do radônio dissolvido por intermédio do equipamento PQ2000PRO da Genitron, que emprega uma câmara de ionização para as medidas das partículas alfa de 5,48 MeV de energia associadas ao 222Rn, isótopo de radônio que possui uma meia-vida de cerca de 3,8 dias. O dispositivo é equipado com uma interface especializada (AquaKIT) e uma bomba de ar (AlphaPUMP) que permitiram efetuar a extração e análise do radônio nas diferentes fases presentes em cada ensaio realizado. A transferência de 222Rn para os derivados de petróleo foi mais acentuada do que para a água destilada, comprovando os resultados de estudos prévios descritos na literatura. Os dados obtidos neste estudo são relevantes para abordagens com foco na presença de contaminantes orgânicos originados em áreas onde ocorreram vazamentos de combustíveis, podendo também ser de futura utilidade no enfoque de questões relacionadas com a qualidade radiológica das águas devido a presença de radônio dissolvido.
Laboratory experiments carried out in the laboratory on the time scale of about 25 to 210 days were performed to evaluate the transfer of radon from different minerals (tantalite, cassiterite and columbite) to solutions consisting of distilled water and the following petroleum by products: gasoline mixed with anhydrous alcohol (27%), gasoline used in aviation, diesel oil and kerosene. The concentration of uranium in the minerals varied from 421 to 1700 ppm, and other tests were also carried out using solutions containing dissolved uranyl nitrate and radium-226 standard solution with a known activity value (2 nCi = 74 Bq). A total of 61 readings of the activity concentration of dissolved radon were carried out using Genitron's PQ2000PRO equipment, which uses an ionization chamber to measure alpha particles of 5.48 MeV energy associated with 222Rn, an isotope of radon that has a half-life of about 3.8 days. The device is equipped with a specialized interface (AquaKIT) and an air pump (AlphaPUMP) that allowed the extraction and analysis of radon in the different phases present in each test carried out. The transfer of 222Rn to petroleum by products was more pronounced than to distilled water, confirming the results of previous studies described in the literature. The data obtained in this study are relevant for approaches focusing on the presence of organic contaminants originating in areas where fuel leaks occurred, and may also be of future use in addressing issues related to the radiological quality of water due to the presence of dissolved radon.
Laboratory experiments carried out in the laboratory on the time scale of about 25 to 210 days were performed to evaluate the transfer of radon from different minerals (tantalite, cassiterite and columbite) to solutions consisting of distilled water and the following petroleum by products: gasoline mixed with anhydrous alcohol (27%), gasoline used in aviation, diesel oil and kerosene. The concentration of uranium in the minerals varied from 421 to 1700 ppm, and other tests were also carried out using solutions containing dissolved uranyl nitrate and radium-226 standard solution with a known activity value (2 nCi = 74 Bq). A total of 61 readings of the activity concentration of dissolved radon were carried out using Genitron's PQ2000PRO equipment, which uses an ionization chamber to measure alpha particles of 5.48 MeV energy associated with 222Rn, an isotope of radon that has a half-life of about 3.8 days. The device is equipped with a specialized interface (AquaKIT) and an air pump (AlphaPUMP) that allowed the extraction and analysis of radon in the different phases present in each test carried out. The transfer of 222Rn to petroleum by products was more pronounced than to distilled water, confirming the results of previous studies described in the literature. The data obtained in this study are relevant for approaches focusing on the presence of organic contaminants originating in areas where fuel leaks occurred, and may also be of future use in addressing issues related to the radiological quality of water due to the presence of dissolved radon.
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Radônio, Derivados de petróleo, Minerais radioativos, Contaminação, Radon, Radioactive minerals, Petroleum by products, Contamination