Bottom-up and up-down strategy to obtain the highly porous polystyrene foam for oily water remediation

Bottom-up and up-down strategy were adopted simultaneously to fabricate the interconnected porous polystyrene monolith based on the high internal phase emulsions (HIPEs) technique. Interface-initiated polymerization strategy of the HIPEs combined with porogen toluene molecule offered an attractive route to fabricate the ultra-light polystyrene foam. High porosity and extra-light density endowed the polystyrene foam with outstanding oil adsorption performance towards a wide range of oil/organic solvents and diesel adsorption capacity exceeded 75.1 g/g. For recyclability, the oil adsorbed in the monolithic polystyrene foam was recovered just by means of centrifugation and the deoiling rate was over 90%. Even after ten cycles of adsorption-centrifugation, the material showed little decline in the adsorption capacity. Oleophilicity, hydrophobicity, permeable pore structure, ultra-low density, excellent oil adsorption performance and recyclability, all these features help the polystyrene foam find great application in the field of oil–water separation.