Recent insights into mechanism of modified bio-adsorbents for the remediation of environmental pollutants

Rapid industrialization has exacerbated the hazard to health and the environment. Wide spectrums of contaminants pose numerous risks, necessitating their disposal and treatment. There is a need for further remediation methods since pollutant residues cannot be entirely eradicated by traditional treatment techniques. Bio-adsorbents are gaining popularity due to their eco-friendly approach, broad applicability, and improved functional and surface characteristics. Adsorbents that have been modified have improved qualities that aid in their adsorptive nature. Adsorption, ion exchange, chelation, surface precipitation, microbial uptake, physical entrapment, biodegradation, redox reactions, and electrostatic interactions are some of the processes that participate in the removal mechanism of biosorbents. These processes can vary depending on the particular biosorbent and the type of pollutants being targeted. The systematic review focuses on the many modification approaches used to remove environmental contaminants. Different modification or activation strategies can be used depending on the type of bio-adsorbent and pollutant to be remediated. Physical activation procedures such as ultrasonication and pyrolysis are more commonly used to modify bio-adsorbents. Ultrasonication process improves the adsorption efficiency by 15–25%. Acid and alkali modified procedures are the most effective chemical activation strategies for adsorbent modification for pollution removal. Chemical modification increases the removal to around 95–99%. The biological technique involving microbial culture is an emerging field that needs to be investigated further for pollutant removal. A short evaluation of modified adsorbents with multi-pollutant adsorption capability that have been better eliminated throughout the adsorption process has been provided.