Reviews and perspectives on the separation and characterization techniques of synthetic and natural microfibers

• Separation and characterization techniques of SF and NF. • Electrostatic separations could be promising for the separation of SF and NF. • Visual identification is quick, simple and low cost method for identification of fibers. • Spectral imaging could increase the efficiency of identification of fibers. • Machine learning could be the future of the characterization of SF and NF. Synthetic and natural microfibers, mainly derived from textile sources, are ubiquitous in the environment. Both persist in the environment for varying durations and pose diverse toxicological impacts on the organisms. However, most monitoring and toxicological studies focus only on synthetic microfibers. This is due to their known persistence and non-biodegradability. As a result, natural microfibers are often overlooked, despite their potential toxicological and environmental impacts. This oversight is also due to challenges associated with the separation, quantification, and characterization of both fibers types in environmental samples. Although various techniques have been employed in research, the available information remains fragmented, and, to the best of our knowledge, no comprehensive review currently exists on this topic. Therefore, this review aims to gather and disseminate information regarding separation, quantification and characterization techniques of both synthetic and natural microfibers to facilitate further research in this field.