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Heitmann A.P.,CEFET MG DEMAT | Silva G.C.,Instituto Nacional Of Ciencia E Tecnologia Em Recursos Minerais | Paiva P.R.P.,Instituto Nacional Of Ciencia E Tecnologia Em Recursos Minerais | Ferreira A.M.,CEFET MG DEMAT | Ferreira A.M.,Instituto Nacional Of Ciencia E Tecnologia Em Recursos Minerais
Ceramica | Year: 2014

The treatment of wastewater containing cadmium is of great interest because of its persistence in the environment and the serious diseases that it can cause to humans. In the present work, the magnetic composite Mn3O4/Fe3O4was used as adsorbent of cadmium ion in aqueous medium. The adsorbent material was synthesized and characterized according to the XRD, Raman, TEM and N2 adsorption (BET) techniques. Emphasis was given to the quantification of the phases of the composite by XRD analysis combined with the Rietveld method. The adsorption study was carried out varying the aqueous medium pH and the concentration of cadmium ions in solution. The results show that the cadmium removal by the Mn3O4/Fe3O4 magnetic composite in aqueous medium is pH-dependent duplicating as the pH varies from 3 to 7. The study of immobilization of the contaminant in solution showed significant amounts of adsorption, 12.3 mgCd/g at pH 6 and 13.6 mgCd/g at pH 7 indicating a removal of up to 98% for low ion concentrations, suggesting that the adsorbent has a high potential for removing Cd(II) in aqueous medium.

Silva G.C.,Federal University of Minas Gerais | Silva G.C.,Instituto Nacional Of Ciencia E Tecnologia Em Recursos Minerais | Almeida F.S.,Federal University of Minas Gerais | Almeida F.S.,Instituto Nacional Of Ciencia E Tecnologia Em Recursos Minerais | And 4 more authors.
Materials Research | Year: 2012

The introduction of magnetic properties in adsorbent materials has the aim of improving solid-liquid separation processes. In this work, a magnetic composite was synthesized through the precipitation of manganese oxide in the presence of magnetite particles using O2 as an oxidant. The composite proved to be chemically and physically stable within a wide range of pH values. The composite characterization indicated that hausmannite (Mn3O4) represents the precipitated manganese phase and that magnetite undergoes no phase transformation during the synthesis. The composite and Mn3O4 particles were used to remove As(III) from aqueous solutions. The magnetic composite and Mn3O4 sample presented high and similar affinity for As(III), with maximum sorptive capacities of 14 mgAs gsolid-1 (0.0048 mmolAs m-2solid) and 20 mgAs gsolid-1 (0.0049 mmolAs m-2solid), respectively, at pH 5.0. The combination of an active high surface area sorbent (Mn3O4) with a magnetic phase (Fe3O4) allows for efficient As(III) removal and solid/liquid separation.

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