A Critical Review of Clay Minerals for Groundwater Protection and Treatment

Beneath the Earth’s surface lies a hidden realm of immense environmental and ecological significance—groundwater. This vital resource is faced with increasing threats from a myriad of contaminants, both natural and anthropogenic. Clay minerals, often overlooked components of geological formations, serve as nature’s heroes in protecting and remediating groundwater. This chapter highlights the remarkable role of clay minerals, particularly montmorillonite, in safeguarding groundwater. Their unique physico-chemical properties enable them to function as natural filters, adsorbents, and barriers against pollutants, with exceptional efficiency in ammonium removal through interlayer sites and cation exchange mechanisms. The chapter details how clay minerals manage harmful substances, preventing their spread into aquifers, and examines engineered clay solutions in groundwater remediation, emphasizing advancements in nanotechnology and material science. The chapter also addresses the challenges and limitations of clay minerals in different geological contexts and contamination scenarios, providing a balanced perspective on their role in groundwater protection. By shedding light on these ‘unsung heroes’, we aim to foster a deeper appreciation for the intricate natural systems that help maintain groundwater quality and inspire innovative approaches to water resource management and environmental remediation.