Non-clogging microfluidics-based filter for Microplastics removal

Amir Mohammadimehr, Joan Antoni-Lopez, Angeles Ivon Rodriguez, Ajeet Kaushik, Jasmina Casals-Terré

Universitat Politècnica de Catalunya-Barcelona Tech
Florida Polythecnic University

Particle separation using microfluidics systems has traditionally been applied in several advanced fields like biotechnology, mainly for diagnostics at point-of-care (POC) applications. Currently, the growing awareness of microplastic, a severe environmental pollutant of concern, presence in the water is tilting the focus towards drinking water testing treatment. In POC devices, the ability to separate different cells provides valuable information for diagnostic purposes. In the context of microplastics, the presented 3D printed microfluidic device could be a continuous non-clogging filter for microliter removal.

Microplastics, typically measuring below 5 mm in size, exhibit a variety of shapes and colors, while wastewater treatment plants remove most of particles bigger than 100 microns, smaller ones remain untreated. This study focuses on the isolation of particles particularly those smaller than 20 µm, from a given medium, utilizing a microfluidic device that combines hydrodynamics and density-based separation methods.

To achieve this, we developed an analytical model that analyzes the best performance given the flow rates and the characteristics of the microplastics. The model provides insights into the time spent during separation, separation purity, and throughput. The use of this density-based separation strategy yields a significant increase in purity reaching up to 99%, surpassing previously attained levels.  The 3D printed model has been manufactured and experimentally validated, with good agreement to the anaylical and computational models. The main goal of the present work is to use numerical and experimental methods to provide a deeper understanding of the behavior of suspension flows in the laminar regimes at moderately high solid volume fractions to achieve particle separation and to propose additive manufacturing techniques to validate the numerical models experimentally.