Enhanced removal of microplastics using microflotation

Microplastics (MPs) pose a significant and growing threat to aquatic ecosystems and human health, yet conventional removal technologies such as sedimentation and filtration often exhibit limited efficiency, particularly for particles smaller than 50 μm, or require chemical additives to enhance performance. In this study, it is demonstrated that microflotation, a process leveraging optimized bubble-particle interactions based on small bubble sizes, can achieve high removal efficiencies (84-98 %) for MPs without the need for flocculants, coagulants, or other chemical additives. Using a pilot-scale system, the removal of 30 μm and 100 μm polystyrene particles across a range of environmentally relevant concentrations (2.5-180 mg/L) is tested. By precisely controlling operational parameters, microbubbles were generated with a narrow size distribution (13-75 μm) and a mean diameter of 36-40 μm, ensuring consistent and reproducible performance. Furthermore, the introduction of a novel bubble measurement technique to enhance process monitoring and optimization is presented. Our findings establish microflotation as a robust, scalable, and sustainable solution for MP removal, offering a viable alternative to conventional treatment methods while aligning with global efforts to reduce chemical usage in water treatment.