Application of high gradient magnetic separation for oil remediation using polymer-coated magnetic nanoparticles

Abstract

Abstract Oil can be released into the environment from different sources such as runoff, accidental oil spills and oily wastewater discharges produced during industrial activities and can have dramatic impacts on the environment. The limitations of current clean-up techniques have inspired researchers to study the application of nanotechnology for oil remediation. Previously, we reported excellent oil-removal efficiency of a reference MC252 oil using polyvinylpyrrolidone (PVP)-coated magnetic nanoparticles (NPs) from an oil-water mixture under a wide range of environmentally relevant conditions. In the current report, the same type of NPs were used with a high gradient magnetic separation (HGMS) technique for the rapid removal of oil from oil-water mixtures in a continuous flow system. Using a high magnetic field (0.56 T) and 1 h mixing time, fluorescence and inductively coupled plasma-optical emission spectrometer (ICP-OES) data showed approximately 85–95% oil and NP removal under all conditions. Gas chromatography–mass spectrometry (GC–MS) results show 88 and near 100% removal of alkanes (C9-C22) for experiments in the presence or absence of stainless steel wool, respectively. Continuous use over 7 h of operation (17 L oil-water mixture was treated) showed no reduction in oil and NP removal capacity. Results showed that increasing the magnetic field and inserting stainless steel wool significantly increased oil and NP removal efficiencies. This study shows that using HGMS is a promising technique for oil remediation using PVP-coated magnetic NPs.