Removal of microplastics from wastewater: various methods and functional coating materials

Abstract Microplastics in wastewater pose significant environmental hazards owing to their toxic and bioaccumulative characteristics, rendering them resistant to degradation. Annually, over 1.5 million tons of microplastics infiltrate global waterways. While traditional wastewater treatment methods, including sedimentation and filtration, attain about 60–70 % removal effectiveness and inadequately collect microplastics, advanced techniques utilizing adsorption, electrostatic attraction, and degradation have efficiencies of 95 %, 99 %, and 95 %, respectively. Functionalized coatings, such as hydrophilic and hydrophobic surfaces, magnetic composites, and bio-based polymers like chitosan, can improve the mitigation of microplastic issues, such as membrane fouling. New technologies include photocatalytic TiO 2 -polymer membranes and 3D-printed porous scaffolds that can achieve approximately 90 % effectiveness in hybrid models. Various comparative studies have shown that the efficiencies of conventional sand filters (45–55 %) and basic membranes (65–75 %) can be increased to 82–88 % and 92–96 %, respectively, with coatings such as polydopamine. Despite these promising results, issues such as scalability, coating durability, and cost persist. Future directions include AI-driven material design, circular economy solutions such as enzyme-embedded coatings (with approximately 95 % efficiency), and robust policy frameworks. Incorporating sophisticated, environmentally friendly coatings into wastewater infrastructure offers a sustainable approach to reducing microplastic contamination and promoting global environmental conservation.