Biogenic Nanomaterials as Adsorbents for Mercury Remediation

Mercury has been in the environment since the beginning of time. Natural and anthropogenic activities are the main sources of mercury. The latter is in the top list of most toxic contaminants worldwide. The elimination of mercury from environmental matrices remains a burning issue in research. The traditional physiochemical treatments are considered expensive, and biogenic nanomaterials have gained an increasing attention. Plant extracts have been widely used as reducing and capping agents for the green synthesis of magnetic and metal oxide nanoparticles for the adsorptive removal of mercury in aqueous matrices. The synthesized metal oxide nanoparticles can be reused for at least five consecutive cycles without significant loss of removal efficiency. Additionally, microorganisms such as bacterial biofilms are used for the synthesis of nanoparticles such as bio selenium nanoparticles (SeNPs) for the immobilization of mercury. The synthesized SeNPs significantly reduces Hg⁰ concentration in groundwater due to the reaction between S⁰ and Hg⁰ resulting in the formation of HgSe. Therefore, this book chapter will critically investigate the current and future developments of biologically synthesised nanoparticles for the remediation of mercury from environmental samples.