Navegando por Palavras-chave "Processos Oxidativos Avançados"

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    Aplicação do Percarbonato de Sódio no tratamento de efluente aquoso simulado contendo Amoxicilina utilizando processos oxidativos avançados
    (Universidade Federal de São Paulo (UNIFESP), 2020-10-29) Oliveira, Isaac Henrique Molina de [UNIFESP]; Moraes, José Ermirio Ferreira de [UNIFESP]; Universidade Federal de São Paulo
    The wastewater of the pharmaceutical industry, in many cases, contains residues of several medicines. Antibiotics, for example, are toxic substances that can trigger the growth of resistant microorganisms, leading to a serious public health problem. Advanced Oxidative Processes (AOP) have been widely studied for the treatment of this type of effluent, as they are methods based on the generation of hydroxyl radicals, a highly reactive species, able to destroy several toxic organicsseveral toxic organics. In the present work, the application of sodium percarbonate (SPC) was investigated, as a source of hydrogen peroxide, in the Fenton, photo-Fenton and UV/SPC processessource of hydrogen peroxide, in the Fenton, photo-Fenton and UV/SPC processes was investigated. Amoxicillin, which is one of the most consumed antibiotics in Brazil, was used as a model pollutant, simulating an effluent from the pharmaceutical industry, adopting an initial concentration of 100 mgC L-1. The tests were carried out in a batch system with recirculation, composed of a photochemical reactor coupled to a mixing tank. Experiments were carried out in order to evaluate the influence of the main parameters on the amoxicillin mineralization, such as pH (3 and 10), the type of iron ions source (Fe2+ and Fe3+), the initial concentration of iron ions (0.26; 1.0 and 2.0 mmol L-1) and UV radiation. According to the experimental data obtained, it was possible to observe that the application of SPC showed promising results in the oxidation of amoxicillin, showing mineralization percentages of 65.8% in just 30 minutes and 88.4% in 120 minutes of reaction, by conventional photo-Fenton process (using ions Fe2+). The use of the modified photo-Fenton process (using ions Fe3+) unfolded to be a viable alternative too, reaching a mineralization of 85.7% in 2 hours by the photo-Fenton process. The Doehlert experimental matrix was used to evaluate the modified Fenton and photo-Fenton processes (using ions Fe3+) systematically, evaluating the influence of the molar rate of the SPC solution in terms of the equivalent amount of H2O2 (0.730-2.205 mmolH2O2 min-1) and the initial concentration of ferric ions (0.26-1.56 mmol L-1) in the total organic carbon removal performance. According to the data obtained, for the Fenton process, the most favorable condition was with a high concentration of Fe3+ (1.560 mmol L-1) and a moderate SPC feed rate (1.470 mmolH2O2 min-1). In the case of the photo-Fenton process, for a better removal, low concentrations of Fe3+ (0.585 mmol L-1) and a moderate SPC feed rate (1.470 mmolH2O2 min-1) would be indicated.
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    Estudo da degradação do Bisfenol A em solução aquosa por processo foto-fenton irradiado artificialmente e baixo custo energético
    (Universidade Federal de São Paulo (UNIFESP), 2020-02-14) Fantinati, Leticia [UNIFESP]; Ribeiro, Katia [UNIFESP]; Universidade Federal de São Paulo
    Bisphenol A is a synthetic material used in the production of plastics and resins. And it is considered a chemical endocrine disruptor, known to be an emerging pollutant in several environmental compartments and can cause significant adverse effects on living beings such as cancer, diabetes and autism, among others. Human exposure to bisphenol A occurs mainly because it is commonly used as a raw material in a variety of industrial processes, such as the production of polycarbonate plastic containers and food cans coated with epoxy resins. In Brazil, the legislation does not regulate the maximum allowed concentration of bisphenol A in effluents or bodies of water. Effluent treatment stations equipped with traditional technologies such as activated sludge process, do not satisfactorily reduce chemical endocrine disrupters in effluents. Advanced oxidative processes have been used in the degradation of several emerging pollutants, such as bisphenol A. According to the literature, the rate of degradation increases with the number and potency of lamps, increasing the energy cost of treatment. In the present study, the conditions for degradation of 25 and 50 mg L-1 of bisphenol A were studied in aqueous medium (total volume = 1500 mL), applying the advanced oxidative processes, specifically fenton and photo-Fenton process, using low rated power lamps (6 W). The results showed rapid bisphenol A removal, which was analyzed by high-efficiency liquid chromatography using C18 kinetex reverse column, and mobile acetonitrile/water phase (30/70; v/v). In order to study the effect of Fe 2+ and H2O2 concentrations on bisphenol A degradation, a statistical analysis was performed using the technique of factorial experimental planning. With the results obtained, it was possible to evidence the importance of Fe2+ concentration at the beginning of the reaction. Total Organic Carbon analyses were performed and showed that for degradation of 60 % of total organic carbon, in 60 minutes of reaction, the photo-Fenton process is more efficient, when H2O2 concentrations equivalent to twice the stochiometric value with Fe2+ 10 mg L-1 and irradiation with two UV/Visible OSRAM 6 W lamps were used.