Horizontal low gradient magnetophoresis behaviour of iron oxide nanoclusters at the different steps of the synthesis route

In this study, the use of horizontal low gradient magnetic field (HLGMF) (<100 T/m) for filtration, control and separation of synthesized magnetic nanoparticles (NPs) is investigated. The characteristics of the suspension, size and type of the NPs are considered and discussed. For these purposes, Fe₂O₃ silica-coated nanoclusters of about 150 nm are synthesized by co-precipitation, monodispersion and silica coating. Superconducting quantum interference device, TEM, XRD and ζ potential techniques were used to characterize the synthesized nanoclusters. An extensive magnetophoresis study was performed at different magnetophoretical conditions. Different reversible aggregation times were observed at different HLGMF, at each step of the synthesis route. In particular, differences of several orders of magnitude were observed when comparing citric acid-modified NPs with silica-coated nanoclusters. Reversible aggregation times are correlated to the properties of the NPs at different steps of synthesis route.