Síntese de nanopartículas de óxido de ferro funcionalizadas para remoção de Pb2+
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Data
2016-05-30
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Universidade Federal de Goiás
Resumo
Lead is a heavy metal that can be found in wastewaters of acid battery production, pigment and dye factories, petrochemical and automobile industries. It can cause serious damages to environment and human health even at trace level due to its bioaccumulation capacity. Numerous techniques are used for removal of heavy metals in wastewaters, the adsorption has been a technique of high efficiency and low cost with the use of alternative adsorbents, like nanoparticles. Iron oxide nanoparticles have low toxicity, they are biocompatible, and due to their small size, they have a huge surface area and high reactivity.
In this study, colloidal suspensions of functionalized iron oxide nanoparticles with citrate were prepared using a modified coprecipitation methodology of Fe3+ and Fe2+ ions in basic medium. With the purpose of simplifying the synthesis to possible uses of nanoparticles in large scale, the colloidal suspension was obtained in one step and subsequent steps in the synthesis, such as washing and drying, were dismissed. Moreover, this synthesis does not generate waste, it has low cost, and simple application.
The nanoparticles were characterized by X-ray diffraction, infrared spectroscopy, transmission electron microscopy, point of zero charge, and molar ratio [Fe3+]/[Fe2+]. Colloidal suspensions were used for removal of Pb2+ in synthetic solutions. For this, studies were conducted to evaluate the influence of synthesis modifications in removal of metal ions, the pH and metal concentration effect, as well as the mechanisms of adsorption, kinetic and thermodynamics parameters.
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It was observed that besides the adsorption process, nanoparticles were coagulated and precipitated, up tp 97% of Pb2+ removal in was obtained in high metal concentration. Thus, due to coagulation another step of separation was not necessary, which could be costly in wastewater treatment.
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Nanopartículas , Magnetica , Maghemita , Adsorção , Coagulação , Nanoparticles , Magnetite , Maghemite , Adsorption , Coagulation
Citação
MATOS, H. L. S. Síntese de nanopartículas de óxido de ferro funcionalizadas para remoção de Pb2+. 2016. 90 f. Dissertação (Mestrado em Engenharia Química) - Universidade Federal de Goiás, Goiânia, 2016.