Recent advances made in the synthesis of nanomaterials/nanoparticles combined with AMD treatment/resource recycling - A review

Acid mine drainage (AMD) causes serious ecological and environmental pollution problems, which is now a worldwide concern due to the large amounts of toxic metallic elements/metalloids components. How to treat AMD and recover/reuse its valuable resources has become one of the most significant research topics in what is known as the resource-based circular economy. In this review, recent advances in research are discussed regarding AMD in terms of formation, hazards, treatment technologies, as well as synthesis of nanomaterials combined with high value utilization or recycling of resources. Firstly, the process of forming AMD and its hazards to the mine location environment, including soil and water, were described. Secondly, the recovery of valuable resources such as Cu, Fe, Al and rare earth elements from AMD and their several kinds of applications (catalysts, synthesis of nanomaterials, semiconductors, etc.) are summarized. Thirdly, the advantages and disadvantages of the various technologies currently available for treating AMD and their present status of research are analyzed, which indicates that adsorption is one of the major contentious topics of research and is described in detail. Then, various methods and mechanisms for the synthesis of adsorbent nanomaterials such as common chemical and biological methods and their applications in AMD treatment/resource recovery were introduced. Finally, recent achievements and fresh insights into the integration of AMD treatment with the synthesis of nanomaterials were comprehensively presented, which include the synthesis of nanomaterials in AMD and the simultaneous recovery of valuable metals based on a variety of methods such as chemical, biological, and industrial waste. We aim to contribute some new light to future research by presenting these advances and challenges regarding nanomaterials synthesis and AMD treatment/resource reuse.