Preparation of P507-containing monodisperse magneto-permeable polystyrene swelling microspheres for extraction of low-concentration scandium from simulated red mud liquor

Preparation process of monodisperse magnetically permeable polystyrene microspheres. • Magnetically permeable swollen polystyrene microspheres containing P507 can serve as a microextraction material. • The microspheres rapidly extract Sc 3+ from simulated red mud liquor, reaching equilibrium in 8 min at O;A phase ratios of 1:40–1:80. • The organic liquid content and polystyrene content in the microspheres are 21% and 27%, respectively. In this study, monodisperse polystyrene microspheres with an average particle size of 3.81 μm were first synthesized via dispersion polymerization combined with seed swelling polymerization. The resulting microspheres exhibited a uniform particle size and intact morphology. Subsequently, monodisperse magnetically permeable polystyrene microspheres were fabricated using a swelling–permeation method, which preserved the structural integrity of the microspheres while imparting high saturation magnetization, enabling rapid magnetic separation under an external magnetic field. The extractant P507 and the diluent 1, 2-dichloroethane were then loaded into the microspheres via an emulsion swelling process. The resulting functionalized microspheres featured uniform particle size, strong magnetic responsiveness, superparamagnetism, and favorable stability. Extraction experiments were conducted using a simulated red mud leachate solution containing 20 ppm Sc 3+ . Under conditions of pH 0.5 and an organic-to-aqueous phase ratio (O/A) ranging from 1:40 to 1:100, the extraction equilibrium was achieved within only 2–8 min, with a maximum extraction efficiency exceeding 95%. These results demonstrate excellent rapid mass transfer performance and efficient adsorption.