Study of Micro-Plastics Separation From Sea Water With Electro-Magnetic Force

The method of removing micro-plastics from sea water has been developed using electro-magnetic force. Plastics are difficult to decompose and put a great load on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by ocean currents over long distances, causing global pollution. These are not easily decomposed in the natural environment. The Lorentz force was generated in simulated sea water and its reaction force was applied to the micro-plastic to control their motion. The basic principle of this separation method has already been confirmed by basic experiments. In this study, the magnetic field and current density required to treat seawater containing microplastics using a superconducting magnet with a bore diameter of 5 cm were investigated by simulation. Plastic particles with a diameter of more than 200 μm were targeted for separation, and various conditions for separation were investigated by simulation. As a result, it was shown that good separation efficiency was obtained under the following conditions: flow velocity of 0.2 m/s, electrode size of 150 mm, current density of 0.93 A/cm
²
, and applied magnetic field of 3 T.