4. Conclusion

Oxides and clay minerals have large surface areas and can sorb heavy metals via adsorption and ion exchange, respectively. Sorption of these toxic metals on oxides and clay minerals reduce their concentration and mobility in aqueous solution and natural environment. This review confirms that sorption is highly dependent on pH, equilibration time, initial concentration of adsorbate, type of adsorbent, temperature, type of adsorbent modification and surface area. In addition, most of the adsorption of ions on clays and oxides are best described by Langmuir models and Pseudo-second-order model. Most remediation techniques employ the use of permeable reactive barriers (PBRs) to react the contaminant from groundwater. These barriers can be Fe-oxides, montmorillonite, Mn oxide-coated montmorillonite, Fe-oxide-coated montmorillonite [121]. The review confirmed that both metal oxides and clay have capability of sequestering heavy metals, however, combination of both metal oxides and modified clay have enhanced capability of removing heavy metals from aqueous solution. These inorganic adsorbents has the regeneration and recycling potentials and can be used to remediate and sequester economic metals for commercial purposes, however, this needs future investigation.

Author details

141

Ifeoma Mary Ugwu1

2 Ruhr University Bochum, Germany

provided the original work is properly cited.

\* and Onyedikachi Anthony Igbokwe2,3

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

1 Enugu State University of Science and Technology, Enugu State, Nigeria

3 Federal University Ndufe-Alike Ikwo, Ebonyi State, Nigeria

\*Address all correspondence to: iu1591@my.bristol.ac.uk

Sorption of Heavy Metals on Clay Minerals and Oxides: A Review

DOI: http://dx.doi.org/10.5772/intechopen.80989

Sorption of Heavy Metals on Clay Minerals and Oxides: A Review DOI: http://dx.doi.org/10.5772/intechopen.80989
