磁性可回收氟化石墨烯破乳材料的制备及乳液分离性能

以氟化石墨烯(FG)为原料, 首先制备了水合肼还原的具有一定亲水性的氟化石墨烯(HFG), 然后采用溶剂热法制备了可磁性分离的四氧化三铁负载的氟化石墨烯复合破乳材料(HFG-Fe₃O₄). 分别利用透射电子显微镜(TEM)、 扫描电子显微镜(SEM)、 傅里叶变换红外光谱仪(FTIR)、 X射线粉末衍射仪(XRD)和X射线光电子能谱仪(XPS)对HFG-Fe₃O₄的形貌、 结构和化学性质进行了表征. 最后研究了HFG-Fe₃O₄对含油废水的破乳性能, 探讨了影响其破乳性能的主要因素, 并对其破乳机理进行了分析. 结果表明: HFG-Fe₃O₄是一种表面负载有Fe₃O₄纳米颗粒的二维片状材料, 在最佳剂量为600 mg/L时对酸性和中性含油废水具有良好的破乳效果. 在酸性和中性条件下, 主要是利用HFG-Fe₃O₄与含油废水之间的静电吸引力以及HFG-Fe₃O₄与沥青质之间的π-π相互作用实现油-水分离. 但是, 在碱性条件下, HFG-Fe₃O₄与油滴之间的静电斥力将急剧增大, 最终导致破乳效率降低. 此外, 将磁性回收的HFG-Fe₃O₄循环利用4次后其乳液分离效率并没有明显下降, 表现出优异的循环稳定性.

Preparation of Magnetically Recyclable Fluorinated Graphene and Its Demulsification Performance for Emulsified Oily Wastewater†

Fluorinated graphene(FG) was firstly reduced by hydrazine hydrate to form the hydrophilic FG(HFG), and then magnetic Fe₃O₄ nanoparticles were further grafted onto the surface of HFG to synthesize HFG-Fe₃O₄ composite. The morphology, structure and chemical property of the samples were characterized by TEM, SEM, FTIR, XRD and XPS. In addition, the demulsification performance of HFG-Fe₃O₄ for oily wastewater was investigated and some affecting factors were discussed in detail. Moreover, the demulsification mechanism of HFG-Fe₃O₄ was proposed as well. The results show that the HFG-Fe₃O₄ is one kind of two-dimensional sheet-like material with Fe₃O₄ nanoparticles being uniformly distributed on its surface. The HFG-Fe₃O₄ has good demulsification performance on acidic and neutral oily wastewater, and its optimum dosage is 600 mg/L. Under the acidic and neutral conditions, the electrostatic attraction between HFG-Fe₃O₄ and the oily wastewater, as well as the π-π interaction between HFG-Fe₃O₄ and asphaltenes are the main forces promoting the oil separation from oily wastewater. However, the electrostatic repulsion between HFG-Fe₃O₄ and oily wastewater increases drastically under the alkaline condition, and ultimately results in the reduction of demulsification efficiency. What’s more, HFG-Fe₃O₄ still has excellent demulsification performance after 4 cycles, suggesting it has superior recyclability.