Synthesis and characterization of iron-PVA hydrogel microspheres and their use in the arsenic (V) removal from aqueous solution

[Display omitted] ► Monodisperse iron microspheres were produced by the sol–gel process. ► Mössbauer spectroscopy was used to characterize the iron microspheres. ► Metallic iron microspheres could be produced with an average diameter ⩾80μm. ► Iron oxide microspheres with a mesoporous structure (105m...

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Bibliographic Details
Published in:Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2012-11, Vol.210, p.432-443
Main Authors: Santos, Armindo, de Oliveira, Felipe Wallysson Ferreira, Silva, Francisco Henrique Araujo, Maria, Daniel Andrada, Ardisson, José Domingos, Macêdo, Waldemar Augusto de Almeida, Palmieri, Helena Eugênia Leonhardt, Franco, Milton Batista
Format: Article
Language:English
Subjects:
Adsorption
Applied sciences
Arsenic
Chemical engineering
desorption
Exact sciences and technology
ferrihydrite
goethite
hydrocolloids
Hydrogel
Iron
iron oxides
Microspheres
nanoparticles
Sol–gel process
sorption isotherms
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Summary:[Display omitted] ► Monodisperse iron microspheres were produced by the sol–gel process. ► Mössbauer spectroscopy was used to characterize the iron microspheres. ► Metallic iron microspheres could be produced with an average diameter ⩾80μm. ► Iron oxide microspheres with a mesoporous structure (105m2/g) were obtained. ► Iron-PVA hydrogel microspheres showed high As(V) uptake (87.18mg/g). We adapt the sol–gel process to synthesize monodisperse metallic iron (80–155μm), iron oxide (117–200μm), xerogel (130–224μm), and -PVA hydrogel (300–600μm) microspheres. According to the Mössbauer analysis, iron xerogel and -PVA hydrogel microspheres have superparamagnetic nanoparticles of ferrihydrite (65%) and goethite (35%). Maximum arsenic (V) adsorption (87.18 mgAs/g, ⩾99.40% at t⩾4h) on the iron-PVA hydrogel microspheres takes place in the pH range 2–5, in accordance with the Langmuir model. In this adsorption, chemisorption mechanism is predominant, but the intra-particle diffusion model suggests that the adsorption mechanism is more complex. Desorption can be done with 0.011M NaOH solution, reaching an efficiency of 74.64%. Our sol–gel process is effective in maintaining the iron particles monodisperse and with nanometer dimensions (⩽20nm) inside the iron-PVA hydrogel microspheres.
ISSN:1385-8947
1873-3212
DOI:10.1016/j.cej.2012.08.078