CoFe2O4 functionalized PVDF membrane for synchronous oil/water separation and peroxomonosulfate activation toward aromatic pollutants degradation

Abstract

Effective synchronous removal of water-immiscible oils and water-miscible refractory aromatic pollutants from wastewater is of great significance for water remediation. In this work, a low-cost and easy-prepared composite membrane was fabricated by vacuum assisted assembling of CoFe2O4 and tannic acid on polyvinylidene fluoride (PVDF) substrate. The CoFe2O4 functionalized PVDF membrane (CoFe2O4@PVDF) exhibited in-air superamphiphilic and underwater superoleophobic surface wettability. The resultant membrane displayed relatively favorable permeation flux (811.5 to 1837.5 Lm−2h−1) and high separation efficiency (above 99 %) in the separation of a series of emulsified oils ranged from nanoscale to microscale from water. Meanwhile, the as-fabricated CoFe2O4@PVDF membrane coupled with peroxymonosulfate (PMS) exhibited an extensive oxidizing capacity and high degradation efficiency towards aromatic contaminants with desired mineralization ability. More importantly, considering that the fabricated CoFe2O4@PVDF membrane possessed special super-wettability as well as PMS activation-based catalytic ability, it also applied in the treatment of simulated complex wastewater. The process achieved effectively synchronous oil/water separation and PMS activation toward pollutants degradation. Besides, in five cyclic continuous “degradation-separation” tests, the recovered CoFe2O4@PVDF membrane after PMS-based degradation in each cycle could separate oil/water emulsions as usual. It exhibited almost complete oil rejection and flux recovery property under multicycle filtration, demonstrating its excellent durability and stability. This flexible integration of PMS-based AOP catalytic capability and super-wettability into a composite membrane can provide inspiration for effective complicated wastewater rehabilitation.