Exploring mechanisms, efficiency, and emerging technologies for zero-valent metals in water treatment: A review

Domestic, industrial and agricultural activities require large amounts of water. This necessitates the need for an effective solution to meet the increasing water demand worldwide. A Huge amount of wastewater is generated daily and when this is left untreated, the contaminants present in these effluents may be harmful to the environment. There are various treatment techniques for the abatement of the contaminants present in these wastewaters. Conventional approaches often employed are the biological, physical and chemical methods. Zero-valent metals (ZVMs) such as zero-valent iron, zero-valent zinc, zero-valent aluminium to mention a few have emerged as promising candidates for wastewater treatment applications due to their unique reactivity and ability to facilitate the removal of various contaminants. In this report, a comprehensive review of the mechanisms, efficiency, and emerging technologies associated with ZVM-based water treatment is provided. The underlying objectives for which the review aimed to address include (i) providing an understanding of the ZVMs used in water treatment applications and their properties, (ii) reviewing the mechanisms employed by ZVMs to sequestrate contaminants, (iii) evaluating the efficiency of ZVMs in the removal of contaminants and (iv) exploring the various emerging technologies used in ZVM-based water treatment and to provide some recommendations for future research.It was concluded from the work that ZVMs abate contaminants found in wastewater through an interplay and synergy of physical, chemical and catalytic mechanisms. ZVMs, when used with other treatment techniques, provide better benefits in the treatment of diverse contaminants. To help achieve the full scale utilization of ZVMs potential, sustained research efforts combined with innovative approaches are needed for sustainable and efficient water treatment solutions. The review offers insights into technologies needed to eliminate diverse contaminants from wastewater, addressing important considerations regarding sustainability and future directions of ZVM-based water treatment technologies.