Sustainable Bio-Nanocomposites from Biomass Waste for the Efficient Removal of Heavy Metal Ions

Abstract:

Achieving universal access to safe drinking water by 2030 is a sixth sustainable development goal, underlining the fundamental human right to clean water. Heavy metal pollution associated with industrialisation poses a major threat to the environment. Although nanomaterials have high adsorption potential, their effectiveness is limited by problems such as agglomeration. Bionanocomposites combine nanomaterials with biological materials, using their functional groups to improve adsorption and promote waste reuse to promote sustainability. This review thoroughly covers the synthesis and use of bio-nanocomposites from waste from plant and animal biomass for the removal of heavy metal ions from water. The composites developed under this heading include cellulose nanocrystals, cellulose nanofibers, carbon-based composites, lignin-based composites, biochar derivatives, chitosan-based composites and cross-linked hydrogel beads. The review focuses on batch adsorption studies with emphasis on variables that influence adsorption performance, such as pH, contact time, adsorption concentration, initial concentration of metal ions and temperature. In addition, it explores the potential of bio-nanocomposites from plant materials (e.g. cellulose, lignin, biochar and starch) and animal materials (e.g. fish scales, chitons, shellfish, feathers, fur and bones of animals) to remove heavy metal ions. Recent bio-nanocomposites and their adsorption efficiency are summarised and highlighted with a focus on their applicability to environmentally friendly water treatment processes.