Adsorption-desorption mechanism of phosphate by immobilized nano-sized magnetite layer: Interface and bulk interactions

► Phosphate was initially bonded onto the Fe3O4 surface via bidentate complexation then diffused into the interior layer. ► Phosphate desorption, by alkaline eluent, was predominantly a surface reaction. ► Five successive fix-bed adsorption/regeneration cycles were successfully applied. ► Innovative correlation of adsorption-desorption performance with diffusion mechanism is presented.