Navegando por Palavras-chave "Photo-Fenton"
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- ItemAcesso aberto (Open Access)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 PauloBisphenol 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.
- ItemSomente MetadadadosPhoto-Fenton oxidation of phenol and organochlorides (2,4-DCP and 2,4-D) in aqueous alkaline medium with high chloride concentration(Elsevier B.V., 2012-11-30) Luna, Airton J.; Chiavone-Filho, Osvaldo; Machulek, Amilcar; Moraes, Jose Ermirio F. de [UNIFESP]; Nascimento, Claudio A. O.; Natl Inst Ind Property; Univ Fed Rio Grande do Norte; Universidade Federal de Mato Grosso do Sul (UFMS); Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)A highly concentrated aqueous saline-containing solution of phenol, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2.4-DCP) was treated by the photo-Fenton process in a system composed of an annular reactor with a quartz immersion well and a medium-pressure mercury lamp (450 W). the study was conducted under special conditions to minimize the costs of acidification and neutralization, which are usual steps in this type of process. Photochemical reactions were carried out to investigate the influence of some process variables such as the initial concentration of Fe2+ ([Fe2+](0)) from 1.0 up to 2.5 mM, the rate in mmol of H2O2 fed into the system (F-H2O2,F-in) from 3.67 up to 7.33 mmol of H2O2/min during 120 min of reaction time, and the initial pH (pH(0)) from 3.0 up to 9.0 in the presence and absence of NaCl (60.0 g/L). Although the optimum pH for the photo-Fenton process is about 3.0, this particular system performed well in experimental conditions starting at alkaline and neutral pH. the results obtained here are promising for industrial applications, particularly in view of the high concentration of chloride, a known hydroxyl radical scavenger and the main oxidant present in photo-Fenton processes. (C) 2012 Elsevier B.V. All rights reserved.