Could microwave induced catalytic oxidation (MICO) process over CoFe2O4 effectively eliminate brilliant green in aqueous solution?
In this study, we adopted the chemical co-precipitation (CP) method and sol-gel method followed by calcination at temperatures of 100-900°C for 12h to synthesize CoFe2O4 materials, which were further characterized by TEM, XRD and XPS techniques. The properties of CoFe2O4 materials were evaluated in a microwave (MW) induced catalytic oxidation (MICO) process for the elimination of brilliant green (BG). The results showed that: (1) the removal rates of BG gradually decreased over a series of CoFe2O4 materials prepared by CP method and calcinated with 100-700°C (except 900°C) for 12h within three reuse cycles; for comparison, no removal of BG was obtained over CoFe2O4 synthesized by sol-gel method and CoFe2O4-900 (CP); (2) no hydroxyl radicals were captured with salicylic acid used as molecular probe in the MICO process; (3) MW irradiation enhanced the release of residual NaOH within the microstructure of CoFe2O4 and further discolored BG, because BG is sensitive to pH; (4) granular activated carbon (GAC), an excellent MW-absorbing material possessing higher dielectric loss tangent compared to that of a series of CoFe2O4 materials, could not remove BG in suspensions at a higher efficiency, even if the loading amount was 20 g L(-1). Accordingly, MICO process over CoFe2O4 materials and GAC could not effectively eliminate BG in suspensions.
South China Institute of Environmental Science, Ministry of Environmental Protection (MEP), Guangzhou 510655, PR China. Electronic address: juyongming@scies.org.
Yongming
Y
Ju
Xiaoyan
X
Wang
Junqin
J
Qiao
Guohua
G
Li
You
Y
Wu
Yuan
Y
Li
Xiuyu
X
Zhang
Zhencheng
Z
Xu
Jianying
J
Qi
Jiande
J
Fang
Dionysios D
DD
Dionysiou
D000327:Adsorption; D002384:Catalysis; D002606:Charcoal / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D046529:Microscopy, Electron, Transmission; D008872:Microwaves; D010100:Oxygen / Q000737:chemistry; D044367:Phase Transition; D000644:Quaternary Ammonium Compounds / Q000032:analysis*; D020156:Salicylic Acid / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
D005290:Ferric Compounds; D000644:Quaternary Ammonium Compounds; D012997:Solvents; D014874:Water Pollutants, Chemical; C001215:ferrite; D002606:Charcoal; D017665:Hydroxyl Radical; D003035:Cobalt; D012972:Sodium Hydroxide; C006798:brilliant green; D020156:Salicylic Acid; D010100:Oxygen
Brilliant green; CoFe(2)O(4); Dielectric loss tangent; Microwave induced catalytic oxidation (MICO); Wastewater treatment