Desenvolvimento de uma metodologia para determinação de Pb2+ em matrizes aquosas utilizando nanopartículas magnéticas
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Data
2018-04-20
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Editor
Universidade Federal de Goiás
Resumo
The iron oxide (Fe3O4) nanoparticles are promising adsorbents and, in this work,
they were synthesized, characterized and applied as adsorbents in the
adsorption of lead ions (Pb2+) using solid phase magnetic extraction (MSPE). The
iron oxide was synthesized by the coprecipitation method and the obtained
nanoparticles presented the crystalline phase of the oxide, being proved by the
characterization by X-Ray Diffraction, X-ray Dispersive Energy and Absorption
Spectroscopy in the Infrared region. In order to obtain information on the surface
charge of the synthesized material, the pH at the zero loading point (pHPCZ) was
determined indicating that the oxide surface is negatively charged at pH values
above 9.4. Once the best pH (9.0) for adsorption was defined, the influence of
the variables agitation time and mass of the adsorbent were evaluated, fixing
them in 4 min and 3.0 mg respectively, in order to obtain the best conditions of
the adsorption. adsorption process. The maximum adsorption capacity was
obtained by the construction of adsorption isotherms, and a value of 31.60 mg.g1
was found. Through the kinetic study, it was observed that the adsorption obeys
a pseudo-first-order kinetics. After the adsorption was optimized, the best
desorption parameters were evaluated, aiming the development of an
extraction/preconcentration method. Thus, 500μL of 0.5 mol.L-1 nitric acid was
used as the eluent. The analytical performance was evaluated by means of the
parameters, limit of detection (L.D.), limit of quantification (L.Q.), precision
(D.P.R) and values found were 5.44 μg.L-1
; 16.48 μg.L-1 and 0.25%, respectively,
with the linear range of the method being 16.48 -500 μg.L-1
. Finally, the accuracy
of the method was evaluated from recovery tests on samples of mineral water,
micellar water and facial makeup with recovery values in the range of 95.94 -
118%. In addition, analyzes of certified water reference material (APS-1071)
were also made to verify the accuracy of the proposed method.
Descrição
Palavras-chave
Óxidos de ferro, Extração magnética em fase sólida, Chumbo, Adsorção, Iron oxides, Solid phase magnetic extraction, Lead, Adsorption
Citação
SILVA, C. A. S. Desenvolvimento de uma metodologia para determinação de Pb2+ em matrizes aquosas utilizando nanopartículas magnéticas. 2018. 83 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Catalão, 2018.