Embodiments of the present disclosure include separating devices and systems and methods of use. Embodiments of the present disclosure include separation devices including magnetic arrays and sheet-flow separation chambers. In an embodiment, the separating device enables the generation of multiple, and in some configurations, intersecting, high gradient magnetic field lines, resulting in strong separation forces, which permit for scale up to large areas and/or volumes (e.g., extracorporeal blood filtration system).