Читать книгу Application of Nanotechnology in Mining Processes - Группа авторов - Страница 12

Anyik John Leo1,2*, Innocentia Gugulethu Erdogan1,3, Frans B. Waanders1, Martin Mkandawire1,2, Thabo T.I Nkambule4, Bhekie B. Mamba4 and Elvis Fosso-Kankeu4,5

¹ Water Pollution Monitoring and Remediation Initiatives Research Group, School of Chemical and Minerals Engineering, North-West University, Potchefstroom, South Africa

² Solid-State Research Group, Department of Chemistry, School of Science and Technology, Cape Breton University, Sydney, Canada

³ Faculty of Engineering and the Built Environment, Chemical Engineering Department, Cape Peninsula University of Technology, Cape Town, South Africa

⁴ Institute for Nanotechnology and Water Sustainability (iNanoWS), College of Science Engineering and Technology (CSET), University of South Africa, Florida Science Campus, Johannesburg, South Africa

⁵ Department of Electrical and Mining Engineering, College of Science Engineering and Technology (CSET), University of South Africa, Florida Science Campus, Johannesburg, South Africa

Abstract

Mining supplies key resources necessary for technological advancement to ameliorate challenges imposed by the increase in the human population worldwide. One of the legacies of mining resources is the formation and discharge of acid mine drainage (AMD) during and even after active mining. It is a major environmental concern because it enhances the dissolution and increases the dispersion of contaminants, mostly toxic metals, in the environment. Many countries have now adopted or promulgated legislation that requires mining operators to treat and manage the formation of AMD, costing them a fortune from their profits. AMD can be an alternative source of valuable rare earth elements (REE), but the currently available extraction methods of REE from AMD are inefficient and costly, exceeding by many folds their conventional extraction from ores. Thus, there has been a growing effort to develop a novel and cost-effective method to recover REEs from AMD, in which extraction using polymeric nanomaterials, like Poly(amidoamine) (PAMAM) dendrimers, are growing in prominence. PAMAM dendrimers nanoparticles have high adsorption capacity, contributing highly to metal recovery from most wastewater. However, their application in the recovery of REEs from AMD is hampered by the low pH of the AMD, which protonates the amine functional groups forming cationic charges on the surfaces of the dendrimer nanoparticles. Therefore, designing these materials to adsorb metal ions in an acidic solution is paramount for treating AMD. This chapter discusses designing a cost-effective method for the recovery of REEs from AMD after alkaline treatment, using surface-functionalized magnetic PAMAM dendrimer nanoparticles. The environmental effect and shortcomings of AMD remediation methods will be highlighted as a background motivation in developing this procedure.

Keywords: Acid rock drainage, dendrimers, magnetic iron oxides nanoparticle, potentially toxic elements, rare earth element