LEANDRO GOULART DE ARAUJO
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Resumo IPEN-doc 28390 Biossorção de urânio por meio de hidroxiapatita e farinha de osso2021 - WATANABE, TAMIRES; MARUMO, JULIO T.; ARAUJO, LEANDRO G. deArtigo IPEN-doc 27978 Uranium biosorption by hydroxyapatite and bone meal2021 - WATANABE, TAMIRES; GUILHEN, SABINE N.; MARUMO, JULIO T.; ARAUJO, LEANDRO G. deBiosorption has been widely examined for the treatment of aqueous solutions containing uranium, a radiotoxic pollutant. The use of hydroxyapatite and bone meal as potential biosorbents in the removal of uranium (U) from aqueous solutions has not yet been previously addressed. In this work, the efficiency of these biosorbents in the removal of U was investigated according to their adsorption removal capacities. Surface transformations in both materials were observed after U adsorption by scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM/EDS). The biomass/U solution ratio was kept at 0.1 g/5 mL. Contact times for the batch experiments were 15, 30, 60, 120, and 180 min, and the concentration of U tested was 680 mg L-1. The equilibrium was achieved in less than 15 min for both materials. The morphological characteristics of each biomass, before and after biosorption experiments were analyzed. Bone meal highlighted slightly superior adsorption results in terms of maximum capacity (qmax = 33.83 mg g-1), compared to hydroxyapatite (qmax = 33.36 mg g-1), with the removal percentages being also similar, 99.97 and 98.57 %, respectively. The results so far indicate that these materials are potential biosorbents for the treatment of uranium-contaminated solutions, especially liquid radioactive waste.Artigo IPEN-doc 27884 Preliminary studies on electron beam irradiation as a treatment method of radioactive oil sludge2021 - TESSARO, A.P.G.; VICENTE, R.; MARUMO, J.T.; TEIXEIRA, A.C.S.C.; ARAUJO, L.G.Radiation-induced advanced oxidation processes have been proposed for the treatment of various types of wastes. However, electron beam technologies for the removal of recalcitrant compounds in petroleum wastes are still poorly understood. This work aims at evaluating the effects on the degradation of organic matter from oil sludge by electron beam irradiation. Characterization methods were employed to identify the chemical elements present in the waste. Radiometric analysis was performed to identify radionuclides and measure dose rates. Preliminary immobilization of the untreated waste with cement indicated resistance values very close to the minimum established in national regulation. To treat the waste, an electron beam accelerator, model Dynamitron II, with variable current up to 25 mA was employed and the irradiation doses ranged from 20 to 200 kGy. Solutions were prepared with an initial H2O2 concentration of 1.34 mol·L-1. The effects on the removal of total organic carbon are discussed.Resumo IPEN-doc 27532 Biossorção de urânio por meio de hidroxiapatita e farinha de osso2020 - WATANABE, TAMIRES; MARUMO, JULIO T.; ARAUJO, LEANDRO G. de