Fabrication of recyclable multi-responsive magnetic nanoparticles for emulsified oil-water separation. (10th May 2020)

• Record Type: Journal Article
• Authors: Lü, Ting; Qi, Dongming; Zhang, Dong; Fu, Kejing; Li, Yi; Zhao, Hongting
• Is Part Of: Journal of cleaner production. Volume 255(2020)
• Publication Date: 2020-05-10
• Subjects: Magnetic nanoparticles -- Multi-responsive -- Oil-water separation -- Recyclability; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2020.120293
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: In order to promote the convenience and environmental friendliness of recycling process for the magnetic nanoparticles (MNPs) used in emulsified oil-water separation, a series of recyclable multi-responsive MNPs were successfully fabricated via grafting triple sensitive copolymers onto the silica coated ferroferric oxide (Fe3 O4 @SiO2 ) nanoparticles. It was found that the performance of fabricated MNPs was significantly influenced by three environmental parameters, namely pH value, temperature and ionic strength (IS) of water. The synthesized MNPs tended to assemble at oil droplet surface at a temperature less than lower critical solution temperature (LCST), lower pH level or higher IS, thereby facilitating removal of emulsified oil from water phase under external magnetic field. On the contrary, these MNPs could also reversibly desorb form oil droplet surface at a temperature higher than LCST, higher pH level or lower IS. Accordingly, the spent MNPs could be easily regenerated by just regulating solution temperature, pH or IS, rather than by washing with organic solvent, thereby minimizing the risks of secondary pollution. Recycling experiment showed that the well-designed MNPs could be reused up to five cycles without showing remarkable decline in separation efficiency. It's noteworthy that the MNPs exhibited superior separation efficiency at high IS, which is typically encountered for real saline oily water system, thereby spent MNPs could be easily recycled by merely using deionized water due to the dramatical decrease of IS during their rinsing process, suggesting its applicability for practical use. It is expected that the development of this multi-responsive and recyclable MNPs can potentially offer a promising, facile, cost-efficient and eco-friendly route for the emulsified oily wastewater treatment. Graphical abstract: Image 1 Highlights: Temperature, pH and IS-responsive MNPs were fabricated for oil-water separation. The MNPs exhibited superior performance at lower pH, lower temperature or higher IS. Spent MNPs could be regenerated by raising pH, raising temperature or decreasing IS. The MNPs could be recycled at least five times with negligible reduction in efficiency. The MNPs were particularly applicable to treat practical saline oily wastewater.