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Superparamagnetic zinc ferrite spinel-graphene nanostructures for fast wastewater purification

Meidanchi, A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.carbon.2013.12.019
  3. Abstract:
  4. Superparamagnetic ZnFe2O4/reduced graphene oxide (rGO) composites containing ZnFe2O4 nanoparticles (with ∼5-20 nm sizes) attached onto rGO sheets (with ∼1 μm lateral dimensions) were synthesized by hydrothermal reaction method. By increasing the graphene content of the composite from 0 to 40 wt%, the size as well as the number of the ZnFe2O4 nanoparticles decreased and the saturated magnetization of the composites reduced from 10.2 to 1.8 emu/g, resulting in lower responses to external magnetic fields. Concerning this, the time needed for 90% separation of ZnFe2O4/rGO (40 wt%) composite from its solution (2 mg/mL in ethanol) was found 60 min in the presence of an external magnetic field (∼1 Tesla), while using ZnFe 2O4/rGO (15 wt%), only 2 min was required (comparable to the separation time of pure ZnFe2O4 nanoparticles). Correspondingly, the magnetic separation time of 10 μM methyl orange and rhodamine B from aqueous solutions containing 2 mg/mL ZnFe2O 4/rGO (15 wt%) was found <6 min, while using the ZnFe 2O4/rGO (40 wt%) only 15-20% of the dyes could be separated after 16 min. Although the pure ZnFe2O4 nanoparticles could magnetically separate nearly whole of the dyes from the solutions, the separation time was too longer (>16 min)
  5. Keywords:
  6. External magnetic field ; Graphene oxides ; Hydrothermal reaction ; Lateral dimension ; Saturated magnetization ; Separation time ; Superparamagnetics ; Wastewater purification ; Azo dyes ; Dyes ; Graphene ; Magnetic fields ; Magnetic separation ; Nanoparticles ; Separation ; Superparamagnetism ; Zinc compounds ; Synthesis (chemical)
  7. Source: Carbon ; Vol. 69 , April , 2014 , pp. 230-238 ; ISSN: 00086223
  8. URL: http://www.sciencedirect.com/science/article/pii/S0008622313011615