Fundamental Study of the Removal of Microplastic Fibers Using Swirling Flow and Magnetic Field

Abstract

Microplastic fibers (MPFs) derived from laundry wastewater and fishing nets, etc. have been found in the environment around the world, raising concerns about their ecological impact. Particularly for laundry wastewater, some of the MPFs are not removed by sewage plants, and are discharged into the environment. We have studied the removal method of MPFs by magnetic separation in sewage plants, but there were some problems for practical applications such as the desorption of magnetite from MPFs and blockage of magnetic filters. To solve the problems, we proposed a novel magnetic separation system combining swirling flow and opposing magnets. In this study, we investigated whether MPFs can be concentrated by particle trajectory simulations and lab-scale experiments. The simulations and experiments showed similar trends that MPFs can be concentrated by the proposed magnetic separation system. The magnetic separation performance will be improved by using a higher magnetic field of opposed superconducting bulk magnets.