Advances in chitin and chitosan-based materials for microplastics treatment

Microplastics (MPs) have emerged as widespread environmental pollutants in aquatic ecosystems, primarily due to the extensive use of plastic products, their persistent nature, and improper disposal methods. It is essential to develop effective purification methods to treat the hazardous MPs in water. Chitin and chitosan (CS) have gained attention as promising adsorbents for MPs because of their low cost, abundance, biodegradability, and the presence of functional groups such as amino and hydroxyl groups, which facilitate the removal of various toxins from wastewater. However, challenges such as low selectivity, limited mechanical strength, and solubility in acidic environments have constrained their practical applications. Numerous modifications to the physicochemical properties of chitin and CS have been investigated to overcome these challenges. In this review, we summarized the sources, extraction techniques, and properties of chitin and CS. What's more, we focused on the application of chitin and CS-based materials for the removal of MPs from wastewater, including adsorption, coagulation-flocculation, membrane technology, and air flotation technology.