Removal of micro- and nano-plastics from aqueous matrices using modified biochar – A review of synthesis, applications, interaction, and regeneration

• Modified biochars are used for efficient removal of micro- and nano-plastics from water matrices. • Synthesis techniques for biochar consist chemical functionalization and nanoparticle integration. • The interaction mechanisms between modified biochar and microplastics are critical water treatment. • Critical evaluation of challenges in biochar regeneration is also crucial for sustainable reuse. The widespread contamination of aquatic environments by micro- and nano-plastics has become a global environmental concern that is demanding effective remediation strategies. The main objective of this paper is to find the application of modified biochar in micro- and nano-plastic removal from aqueous environments. In this paper, the synthesis of modified biochar, encompassing various modification techniques such as chemical functionalization, physical activation, and nanoparticle incorporation, is systematically explored. The intricate interaction mechanisms between modified biochar and microplastics are dissected by considering physical adsorption, chemical interactions, electrostatic forces, and hydrophobic interactions. The regeneration of biochar for repeated use is critically evaluated by emphasizing the challenges associated with structural changes and the loss of functional groups during regeneration processes. This review paper integrates findings from recent studies and identifies research gaps by offering insights into the optimization of biochar-based materials for sustainable and efficient removal of microplastics from aqueous matrices. It also guides future research endeavors and technological advancements in plastic pollution mitigation using sustainable materials.