Improving urban run-off quality using iron oxide nanoparticles with magnetic field

Abstract

Runoff from roads surface is a major source of pollution in the environment. The aim of this study was to investigate the efficiency of nano iron oxide under a magnetic field to improve urban runoff quality.Experiments were conducted in 50 mm diameter column made of plexiglass in which 20 cm deep stainless steel wool was used as medium bed. A pair of magnets, each with 0.7 T magnetic charge density was installed around the column. The particle size of the iron oxide was determined by X-ray diffraction (XRD) analysis. Atomic absorption spectroscopy, spectrophotometer, turbidimeter and pH meter were used to measure heavy metals, nitrate and phosphate, turbidity and pH, respectively.Results from XRD analysis revealed that the average nanoparticles size was 32 nm. The average removal efficiency for turbidity, Pb, Zn, Cd and phosphate were 41.5%, 93.9%, 96.2%, 88.4% and 87.4%, respectively. However, nitrate was not removed from the column tests.The results of this study showed that nano iron oxide in presence of magnetic field has potential to improve urban runoff quality. However, for further reduction of turbidity and nitrate removal other options should be considered.