Biosorption of heavy metal ions from contaminated wastewater: an eco-friendly approach

Several industries such as leather tanning, coal mining, steel and metal processing are responsible for heavy metals contamination in water. Heavy metals contamination in water can have harmful effects on both aquatic and terrestrial animals by entering the food chain. Due to the higher toxicity of heavy metals, it is necessary to remove heavy metal ions from water. There are several physio-chemical methods available, including ion exchange, membrane filtration, chemical oxidation, and electrochemical methods. However, these methods have some disadvantages like expensive and generating harmful byproducts. Biosorption is a cost-effective and eco-friendly method for the removal of heavy metals from contaminated water. Biosorbents are derived from biomasses of plant, bacterial, algal, fungal, agro-waste, etc. The biosorbents have several functional groups on their surface providing them a high binding capacity for heavy metal ions. Mathematical models such as isotherms, thermodynamics, and kinetic studies help explain how heavy metals adsorb on biosorbents. This review provides comprehensive details on the heavy metals heavy metal contaminated in water including the source, toxicity and biosorption of heavy metal ions. This review also provides the mechanism of heavy metal biosorption including mathematical models.