“…have some limitations. − Many of them cannot be considered green because of the associated secondary pollution, high energy requirements, and high cost. , Sorption methods are widely used in many industrial applications, including wastewater treatment . The high cost and the poor biodegradability of some of the newly developed nanostructured sorbents can hinder commercialization. , Aiming for a sustainable solution, green and eco-friendly sorbents need to be developed. , The valorization of biowaste and applying the biorefinery approach are focus areas nowadays, while biopolymers are promising candidates for metal ion binding. ,− …”