Speaker
Description
A method of removing microplastics from seawater using electromagnetic force was devised and its feasibility was demonstrated by calculation. Plastic is difficult to decompose and puts a heavy load on the marine environment. In particular, plastics smaller than 5 mm are defined as microplastics, which are carried over long distances by ocean currents and cause global pollution. The development of technology to remove microplastics from the ocean is an urgent issue.
The developed method is to induce Lorentz force in seawater and applying the reaction force to microplastic. The substances calculated was polyethylene as microplastic. A square pipe with a cross section of 35 mm x 35 mm is placed in a room temperature bore 50 mm of superconducting magnet, and seawater in which polyethylene is dispersed flows vertically upward. On the facing wall two electrodes were placed in the region where the external magnetic field is 3T and then the directions of the current and the magnetic field are vertical. When an electric current is passed, Lorentz force is induced in seawater and a reaction force in the opposite direction apply to the polyethylene. This reaction force can be used to accumulate the polyethylene particles.
The length of the electrode was 40 mm, and the microplastic was considered to be spherical, and the diameter was changed to 1, 3, and 5 mm. The current density was changed so as to JxB are from 2.8x103 to 2.8x104 (N / m2). The average flow velocity was set at 1 m / s, and a parabolic flow velocity distribution was assumed. The calculation results showed that 95% recovery is possible with polyethylene with a diameter of 1 mm. The results suggest that the possibility of separation of microplastics from seawater was shown.
