Ren Anhua, Rius-Ayra Oriol, Kang Min, Llorca-Isern Nuria
College of Engineering, Nanjing Agricultural University, No. 40 Dianjiangtai Road, Nanjing 210031, China.
CPCM Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1 - 11, 08028 Barcelona, Spain.
Langmuir. 2024 Oct 15;40(41):21533-21546. doi: 10.1021/acs.langmuir.4c02420. Epub 2024 Oct 6.
Microplastic pollution has become a primary global concern in the 21st century. Recyclable magnetic particles with micro-nanostructures are considered an efficient and economical way to remove microplastics from water. In this study, superhydrophobic magnetic cobalt ferrite particles were prepared by using a simple coprecipitation method combined with surface functionalization. The micromorphology, chemical composition, hysteresis loop, and surface contact angle of the functionalized cobalt ferrite were characterized. The separation efficiency and absorption capacity of cobalt ferrite particles in water-oil separation and microplastic removal were investigated. The results showed that the saturation magnetic field intensity of cobalt ferrite was 65.52 emu/g, the residual magnetization intensity (Mr) was 18.79 emu/g, and the low coercivity was 799.83 Oe. Cobalt ferrites had stable superhydrophobicity in the pH range of 1-13. The separation efficiency of cobalt ferrite powder for four oil-water mixture separations was higher than 94.2%. The separation efficiency was as high as 99.6% in the separation of the hexane and water mixtures. Due to the synergistic effect of the hydrophobic effect and van der Waals force, the functionalized magnetic cobalt ferrite had a high and stable microplastic removal efficiency and capture capacity. The removal efficiency of microplastics was close to 100%, and the capture capacity was 2.56 g/g. After ten microplastic removal cycles, the removal efficiency reached more than 98%, and the surface contact angle was still greater than 150°.
微塑料污染已成为21世纪全球主要关注的问题。具有微纳米结构的可回收磁性颗粒被认为是从水中去除微塑料的一种高效且经济的方法。在本研究中，通过简单的共沉淀法结合表面功能化制备了超疏水磁性钴铁氧体颗粒。对功能化钴铁氧体的微观形貌、化学成分、磁滞回线和表面接触角进行了表征。研究了钴铁氧体颗粒在油水分离和微塑料去除中的分离效率和吸附容量。结果表明，钴铁氧体的饱和磁场强度为65.52 emu/g，剩余磁化强度（Mr）为18.79 emu/g，矫顽力为799.83 Oe。钴铁氧体在pH值为1-13的范围内具有稳定的超疏水性。钴铁氧体粉末对四种油水混合物分离的分离效率高于94.2%。在己烷和水混合物的分离中，分离效率高达99.6%。由于疏水作用和范德华力的协同作用，功能化磁性钴铁氧体具有高且稳定的微塑料去除效率和捕获能力。微塑料去除率接近100%，捕获容量为2.56 g/g。经过十次微塑料去除循环后，去除效率达到98%以上，表面接触角仍大于150°。
