Remoção de metais utilizando o hexadecanoato de sódio
Industrial activities like mining, electroplating and the oil extraction process, are increasing the levels of heavy metals such as Cu, Fe, Mg and Cd in aquatic ecosystems. This increase is related to the discharge of effluents containing trace of this elements above the maximum allowed by law. M...
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| Formato: | Dissertação |
| Idioma: | por |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/19938 |
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| Resumo: | Industrial activities like mining, electroplating and the oil extraction process, are
increasing the levels of heavy metals such as Cu, Fe, Mg and Cd in aquatic ecosystems. This
increase is related to the discharge of effluents containing trace of this elements above the
maximum allowed by law. Methods such as ion exchange, membrane filtration and chemical
precipitation have been studied as a means of treatment of these metals contamination. The
precipitation of metals using anionic surfactants derived from carboxylic acids emerged as an
alternative for the removal of metals from industrial effluents. The reaction between bivalent
ions and these types of surfactants in aqueous solution leads to the formation of metal
carboxylates, which can precipitate in the form of flakes and are subsequently removed by a
process of decantation or simple filtration. In this work the metals extraction is performed by
using the surfactant sodium hexadecanoate as extracting agent. The main purpose was to
study the effect of temperature, solution pH, and concentration of surfactant in the metal
removal process. The statistical design of the process showed that the process is directly
dependent to changes in pH and concentration of surfactant, but inversely proportional and
somewhat dependent to temperature variation, with the latter effect being considered
negligible in most cases. The individual study of the effect of temperature showed a strong
dependence of the process with the Kraft point, both for the surfactant used as extracting
agent, as for the surfactant obtained after the reaction of this surfactant with the metal. From
data of temperatures and concentrations of the surfactant was possible to calculate the
equilibrium constant for the reaction between sodium hexadecanoate and copper ions. Later,
thermodynamic parameters were determined, showing that the process is exothermic and
spontaneous. |
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