Core-shell composite nanoparticles with magnetic and temperature dual stimuli-responsive properties for removing emulsified oil

Core-shell magnetic and thermosensitive composite nanoparticles, named as M-DMEA, were prepared by grafting polyoxyalkylated N , N -dimethylethanolamine onto magnetite (Fe 3 O 4 ) nanoparticles. A series of characterizations were performed to figure out the properties of the as-prepared M-DMEA. The results reveal that the M-DMEA is superparamagnetic and has irregular shape with a core-shell structure. The flocculation performance of M-DMEA in oily wastewater produced from flooding (OWPF) treatment was investigated for the first time. It was found that the M-DMEA could separate emulsified oil droplets from OWPF rapidly under an external magnetic field with high oil removal (92.3% at the dosage of 2.5   g/L) at 65   °C. Moreover, due to its excellent magnetic response, the M-DMEA can be collected and recycled for another 3 cycles. Factors affecting the flocculation performance were discussed in detail. It is anticipated that as-prepared M-DMEA might find its potential application in practical oily wastewater treatment.