Effect of synergistic sorption of Cr(VI) and Mn(II) in aqueous solution using magnetic nanoparticles

ABSTRACT

In this study, the effect of synergistic sorption of Cr(VI) and Mn(II) in aqueous solution removal by synthetic magnetic nanoparticles (Fe₃O₄) was investigated. The results showed that individual removal of Cr(VI) and Mn(II) by Fe₃O₄ nanoparticles was evidently dependent on pH, and the optimum removal condition for Cr(VI) and Mn(II) was at pH 4 and pH 8, respectively. The removal of Cr(VI) with the pre-treated method was slightly higher than simultaneous method at pH 4. However, the removal of Cr(VI) with simultaneous method was significantly higher than pre-treated method at pH 8 of which the removal percentages were 84.9 and 21.5, respectively. At the same time, for the pre-treated and simultaneous method at pH 8, the equilibrium capacity of Mn(II) on Fe₃O₄ nanoparticles was changed from 36.8 to 49.7 mg g⁻¹Fe₃O₄. The XRD patterns after sorption indicated that there is some hematite formation on the Fe₃O₄ surfaces. Therefore, a redox process could happen in the Cr(VI) sorption on the Fe₃O₄ nanoparticles.

Keywords:

• Cr(VI)
• Mn(II)
• Fe₃O₄
• Synergistic sorption

Acknowledgments

This work is supported by the National Natural Science Foundation of China (No. 41003040 and No. 41201487) and the Natural Science Foundation of Tianjin (No. 10JCYBJC06000).