“…In order to solve eqn (1)-( 3), the rate of NP trapping by the wires (K) is required, as well as its dependence on the operating conditions, such as the magnetic field strength used, flow rate and particle concentration; the retention of NPs by a magnetic wire results from the competition of three mechanisms: magnetic interactions, diffusion and convection. 20,33,39,40 Magnetic interactions are responsible for the accumulation of NPs around a wire, creating strong concentration gradients of NPs, thus leading to high diffusion fluxes that tend to counterbalance magnetic interactions. In the absence of convection, at steady state, diffusion and magnetic interaction counterbalance each other.…”