A Review on Removal of Heavy Metals by Biosorption: A Green Technology

Abstract

Heavy metals have been introduced into the environment because of industrialization. It is well known that heavy metals linger in the environment and endanger organisms. Industrial effluents include microorganisms. To counteract the negative impacts of these metals, they have implemented a variety of measures. These tactics can depend on or be independent of metabolism. One such tactic is biosorption, which involves the interaction of metal ions with cell wall-based metal binding proteins. Algae, fungi, yeasts, and bacteria all engage in biosorption. In addition to live things, leftovers of dead microorganisms also possess biosorbent qualities, such as agricultural wastes like husks, seeds, peels, and stalks from various plants. Temperature, pH, the nature of the biosorbents, the surface area to volume ratio, the quantity of biomass, the initial metal ion concentration, and the metal affinity to the biosorbent are some of the variables that influence the rate of biosorption. Biosorption can be explained using several models, including the Freundlich model and the Langmuir model. Utilizing substances such as thiosulfate, mineral acids, and organic acids, biosorbed metals can be recovered. To avoid changing a biosorbent's physical qualities, the desorption agent should be carefully chosen. It concludes that, biosorption is an effective green technology to remove heavy metals from various types of effluents. Keywords: Heavy metals, biosorption, bacteria, algae, fungi, yeasts.