Emerging technologies for microplastic removal from water systems performance environmental and economic evaluation

Microplastic pollution in aquatic systems requires treatment technologies that remove particles while minimizing secondary pollution, toxic transformation products, and operational burdens. This review critically evaluates emerging technologies for microplastic removal and degradation in water and wastewater systems, focusing mainly on studies published between 2021 and 2025. The technologies assessed include adsorption, electrocoagulation, advanced oxidation processes, microbial and enzymatic degradation, ferrate(VI)-based treatments, membrane filtration, flotation-based separation, and thermal or chemical post-treatment strategies. Reported removal efficiencies are often high, particularly for adsorption, electrocoagulation, ferrate-assisted separation, and membrane filtration, with many studies achieving 80–99% particle removal. However, most approaches primarily transfer microplastics from water to sludge, membranes, adsorbents, or concentrated residues rather than achieving complete polymer mineralization. True degradation remains limited and is mainly associated with selected photocatalytic, Fenton-like, ferrate-based, and enzyme-mediated systems, especially for polymers containing hydrolysable bonds such as PET. Key implementation barriers include catalyst recovery, membrane fouling, energy demand, electrode consumption, incomplete degradation, nanoplastic formation, transformation-product toxicity, and limited pilot-scale validation. Economic evidence remains fragmented, with most studies reporting only operational costs and rarely including capital investment, maintenance, regeneration, or life-cycle-related information. Overall, effective microplastic mitigation will require integrated treatment trains that combine separation, degradation, toxicity assessment, and techno-economic evaluation under real-water conditions.