Recent trends in biosorption: the removal of emerging dye pollutants from aqueous medium

Water has historically been one of the most valuable and important natural resources. However, due to fast population growth and industrial developments, the freshwater resources available are diminishing at an astonishing rate. Water contamination by dye pollutants and other contaminants has driven researchers to develop new, effective, eco-friendly, and low-cost approaches for water treatment. Adsorption is one of the more effective tools for the removal of dye pollutants, sometimes at very low concentrations. In the last 10 years, new adsorbent-based biomaterials have been used in wastewater treatment research, whose effectiveness can be enhanced when exposed to several factors such as adsorbent dose, temperature, contact time, agitation speed, initial concentration, particle size, and pH owing to their outstanding physicochemical characteristics, such as chemical stability, recyclability, high adsorption capacity, high surface area, and low cost. This article review summarizes the recent biosorbent preparation and characterization approaches, as well as their adsorption properties, depollution mechanisms, adsorption kinetics, and adsorption–desorption recycling processes. Significant examples are discussed in detail, highlighting the main challenges, cost-effective treatment methods, and prospects in this field.