Efficient Cr(VI) removal from wastewater by activated carbon superparamagnetic composites

Author(s)

Nogueira, Helton P. ^[1] ; Toma, Sergio H. ^[1] ; Silveira, Alceu T. ^[1] ; Carvalho, Alexandrina A. C. ^[1] ; Fioroto, Alexandre M. ^[1] ; Araki, Koiti ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Quim, BR-05508000 Sao Paulo - Brazil

• Document type: Journal article
• Source: Microchemical Journal; v. 149, SEP 2019.
• Web of Science Citations: 0

Abstract

Activated carbon decorated with superparamagnetic iron oxide nanoparticles, AC/SPION, with high efficiency for removal of Cr(VI) from aqueous media in pH 3 to 8 range was realized, by exploiting the adsorption and reducing capability of AC and magnetite nanoparticles, allied to magnetic separation. However, iron(II) species was demonstrated to be very interesting as co-adsorbent since broaden the optimal pH range (pH 4 to 10) and enhance the removal capacity more than four times, by reducing hexavalent chromium to Cr(III) at the same time that produce iron(III) hydroxide, a colloidal material that tend to precipitate on the nanocomposite increasing its adsorption properties. Finally, AC/SPION can be dispersed in water maximizing the efficiency, and the chromium species loaded material can be easily separated with a magnet providing an alternative for the treatment of large volumes of contaminated wastewater. In fact, final effluents with Cr concentrations in the low mu g/L range, suitable for direct disposal according to EPA recommendations, can be produced by the iron(II) assisted process demonstrating its potentiality in real applications. (AU)

• FAPESP's process: 13/24725-4 - Supramolecular chemistry and nanotechnology
• Grantee: Henrique Eisi Toma
• Support Opportunities: Research Projects - Thematic Grants