Author details

3.10 Advantages of using metal oxides and clays for remediation

Advanced Sorption Process Applications

purposes, however, this requires further investigation.

4. Conclusion

investigation.

140

The use of clay minerals and oxides is more effective than using other materials for remediation of heavy metals from the environment. From example, the use of sepioloite is better for remediation of Cd compared to Ca(OH)2 [119]. In addition, clay minerals and oxides can be recycled and regenerated for additional remediation use. For example, synthetic palygorskite-Fe oxide exhibited the capability of removing Pb and three cycles reusable potential and retains it magnetic properties for the removal of the heavy metals [85]. Recovery of metals from sorbents can increase the life cycle and long term remediation cost [120]. The estimated zinc that will accumulate in composite substrate in Force Crag Mine is will amount to €7600 in 10 years, however, removal of this substrate after its exhaustion will cost more than €0.8 M whereas recycling the substrate through acid washing is estimated to cost €155,000 [120]. Similarly, oxides and clay minerals can be recycled and reused for remediation of the contaminant. In addition, these sorbents can be used to remediate economic heavy/rare earth metals for commercial and industrial

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

Ifeoma Mary Ugwu1 \* and Onyedikachi Anthony Igbokwe2,3

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


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

© 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, provided the original work is properly cited.
