12. Recent Updates of Eco-Friendly Heavy Metal Reduction Methods

Rapid industrialization and globalization have become environmental concerns because of their detrimental impact on the ecosystem and humankind. Heavy metals (HMs) including arsenic (III and V), chromium (VI), lead (II), mercury (II), cadmium (II), nickel (II), zinc (II) copper (II), and iron (II) are associated with health issues such as liver failure, kidney damage, various cancers such as skin cancer and gastric cancer, mental health disorder and reproductive dysfunction. Therefore, it is imperative to estimate the heavy metal contamination and take necessary measures for its removal. However, existing techniques tend to be costly and produce substantial amounts of secondary pollutants. This has led to intensifying efforts to develop green eco-friendly HM reduction methods. Considering this, biosorption and bioaccumulation are emerging as greener cost-effective alternative methods for the remediation approach for heavy metal contaminants. Natural materials, including microbial biomass, agricultural waste and by-products, are utilized as biosorbents for heavy metals. Moreover, biomass can undergo physical treatment and chemical treatment before its utilization. Economic viability can be achieved by regeneration of the biosorbent after the adsorption of HM. Industrial-scale metal reduction aims to develop lean manufacturing processes innovative practices such as recyclable catalysts and improved process design to achieve sustainable bulk metal reduction processes. The recent developments and future direction of heavy metal reduction are discussed.