Halloysite Composites with Fe3O4Particles: The Effect of Impregnation on the Removal of Aqueous Cd(II) And Pb(II)

Paulina Maziarz,Jakub Matusik

doi:10.1515/mipo-2017-0014

Abstract

Abstract In this study, halloysite-Fe3O4composites were synthesized by a chemical-precipitation method to facilitate magnetic separation of the sorbents from aqueous solution. The research focused on the effect of Fe3O4phase on the halloysite sorption properties. The X-ray diffraction (XRD) results confirmed successful deposition of Fe3O4particles on a halloysite surface. They showed that the coating with Fe3O4particles enhanced the halloysite adsorption affinity toward Cd(II) and Pb(II). The highest adsorption capacity was determined for the composites having 10% of the surface deposited with Fe3O4. In this case, the adsorption capacity for Cd(II) and Pb(II) was 33 and 112 mmol·kg-1, respectively. The point of zero charge (pHPZC) and desorption results indicated that the removal mechanism of metals is mainly related to chemisorption involving reaction with hydroxyls of either halloysite or Fe3O4phase. The ion exchange is of limited importance due to the low cation exchange capacity (CEC) of halloysite - Fe3O4composites.

Highlights

The wide distribution and increased concentration levels of heavy metals in surface and ground water is mainly due to the discharge of industrial and agricultural wastes
The ion exchange is of limited importance due to the low cation exchange capacity (CEC) of halloysite - Fe3O4 composites
The halloysite peaks on all X-ray diffraction (XRD) patterns were unaltered, which confirms that iron particles

Summary

Introduction

The wide distribution and increased concentration levels of heavy metals in surface and ground water is mainly due to the discharge of industrial and agricultural wastes These contaminants are problematic and harmful due to their non-biodegradable character and tendency to accumulate in living organisms. Several methods are known for water treatment including ion exchange, adsorption, coagulation and filtration, chemical precipitation, membrane processes, and reverse osmosis (Matlock et al 2002; Ozaki et al 2002; Blöcher et al 2003; Dąbrowski et al 2004; Unuabonah et al 2008; Zhang and Hou 2008; Jiang et al 2010; Motsi et al 2011; Matusik, Wścisło 2014; Bajda et al 2015; Koteja, Matusik 2015; Maziarz, Matusik 2016). Since among the various technologies developed for the removal of contaminants, the adsorption processes are the most effective, economical and commonly used, methods for adsorbent separation from the working medium need to be constantly developed

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Conclusion