Preparation of CCO@M-PP MB for Oil–Water Separation

Polypropylene melt-blown nonwoven material (PP MB) was first modified by polydopamine to improve the surface hydrophilicity. Then cobalt hydroxycarbonate Co(CO₃)_0.5(OH)∙0.11H₂O(CCO) was synthesized on the surface of the modified PP MB(M-PP MB) via a simple in suit hydrothermal method, and CCO@M-PP MB was obtained. The results showed that when the ratio of Co(NO₃)₂·6H₂O to CO(NH₂)₂ was 1:5 and the Co(NO₃)₂·6H₂O concentration was 0.03 mol/L, CCO with a sea urchin-like morphology appeared on the surface of M-PP MB. Compared with PP MB, the water contact angle (WCA) of CCO@M-PP MB reduced to 0°. When n-hexane was used as the oil phase, the underwater oil contact angle (UWOCA) of CCO@M-PP MB could be over 140.63°. CCO@M-PP MB could efficiently separate various oil–water mixtures, the oil included n-hexane, petroleum ether, carbon tetrachloride, dichloromethane, peanut oil, and olive oil. When n-hexane was used as the oil phase, the oil–water separation efficiency of CCO@M-PP MB was over 98.76%. Throughout 50 cycles, the oil–water separation efficiency of CCO@M-PP MB was never lower than 97.02%.