Laboratory investigation of a magnetic system used for enhancing the migration of nanoscale zero-valent iron (NZVI)

• The magnetic attraction was used to enhance the migration of NZVI in the underground.
• The NZVI and iron oxides were gathered by the magnet, and it is feasible to avoid the second pollution caused by the site remediation.
• The presence of magnetic field affect the distribution of NZVI in the underground.

In this study, a self-assembled magnetic system was applied for enhancing the migration of nanoscale zero-valent iron (NZVI). The distribution of NZVI in the presence of magnetic field and the gathering of iron by magnet were investigated. The magnetic system was mainly composed of a piece of permanent magnet and a cuboid sink. The strengths of the magnetic field (range from 50 mT to 5 mT) were measured by Gaussmeter instrument. Three groups and each group with nine monitoring wells with different depth were designed to investigate the distribution of NZVI. Compared with the conventional injection technologies, major of NZVI was existed in surficial aquifer in the presence of magnetic field. The magnetic system could prevent the Fe from leaching into the solution through magnetic attraction and the gather efficiency was found 60.1%. It is a good method to avoid the secondary pollution caused by iron.

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