Iron Oxide Nanoparticles in a Dynamic Flux: Implications for Magnetic Hyperthermia-Controlled Fluid Viscosity

Magnetic hyperthermia (MH) is the phenomenon of increasing the temperature of a system with magnetic nanoparticles (NPs) subjected to an alternating magnetic field (AMF). This phenomenon occurs as the energy from the magnetic field is transformed into heat by mechanical (Brownian relaxation) and/or magnetic (Neel relaxation) magnetization reversal. In this work, we developed an experimental setup to test the use of MH for industrial applications. The liquid's viscosity decreases as the temperature increases, and liquids with high viscosity are present in several industries (e.g., O&G, pharmaceutical, chemical, and food), where a reduction in viscosity can translate into lower costs and greater profitability, for instance, in some industries, by decreasing the pressure drop and hence increasing the flow rate and in others by avoiding problems that occur at low temperature. Our pilot apparatus was built to investigate the hyperthermia effect when a mixture of viscous liquids and NPs, with an average size of 8 nm (transmission electron microscopy), flows through an AMF. In this study, three different configurations were tested, two static, with mixture samples of 1 and 100 mL, and one under dynamic flowing conditions. Two important results should be highlighted: (1) static experiments with 1 and 100 mL had similar SAR [W/g] values, demonstrating the viability of scaling up and (2) there was an increase in the temperature of the colloid flowing through the AMF. It was therefore possible to observe a clear increase in the liquid's temperature when subjected to an AMF, for all condition cases. The results suggest that this technology can be applied on an industrial scale by optimizing the coils and NP properties.