Advanced oxidation processes are widely applied to removal of persistent toxic substances from wastewater by hydroxyl radicals(·OH),which is generated from hydrogen peroxide(H2O2)decomposition.However,their pract...Advanced oxidation processes are widely applied to removal of persistent toxic substances from wastewater by hydroxyl radicals(·OH),which is generated from hydrogen peroxide(H2O2)decomposition.However,their practical applications have been hampered by many strict conditions,such as iron sludge,rigid pH condition,large doses of hydrogen peroxide and Fe^2+,etc.Herein,a magnetically recyclable Fe3O4@polydopamine(Fe3O4@PDA)coreshell nanocomposite was fabricated.As an excellent reducing agent,it can convert Fe^3+to Fe^2+.Combined with the coordination of polydopamine and ferric ions,the production of iron sludge is inhibited.The minimum concentration of hydrogen peroxide(0.2 mmol/L and Fe^2+(0.18 mmol/L))is 150-fold and 100-fold lower than that of previous reports,respectively.It also exhibits excellent degradation performance over a wide pH range from 3.0 to 9.0.Even after the tenth recycling,it still achieves over 99%degradation efficiency with the total organic carbon degradation rate of 80%,which is environmentally benign and has a large economic advantage.This discovery paves a way for extensive practical application of advanced oxidation processes,especially in environmental remediation.展开更多
Magnetic Fe^0/Fe3O4/graphene has been successfully synthesized by a one-step reduction method and investigated in rapid degradation of dyes in this work. The material was characterized by N2 sorption–desorption, scan...Magnetic Fe^0/Fe3O4/graphene has been successfully synthesized by a one-step reduction method and investigated in rapid degradation of dyes in this work. The material was characterized by N2 sorption–desorption, scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FT-IR）, vibrating-sample magnetometer（VSM） measurements and X-ray photoelectron spectroscopy（XPS）. The results indicated that Fe^0/Fe3O4/graphene had a layered structure with Fe crystals highly dispersed in the interlayers of graphene, which could enhance the mass transfer process between Fe^0/Fe3O4/graphene and pollutants. Fe^0/Fe3O4/graphene exhibited ferromagnetism and could be easily separated and re-dispersed for reuse in water. Typical dyes, such as Methyl Orange, Methylene Blue and Crystal Violet, could be decolorized by Fe^0/Fe3O4/graphene rapidly. After 20 min, the decolorization efficiencies of methyl orange, methylene blue and crystal violet were 94.78%, 91.60% and 89.07%, respectively. The reaction mechanism of Fe^0/Fe3O4/graphene with dyes mainly included adsorption and enhanced reduction by the composite. Thus, Fe^0/Fe3O4/graphene prepared by the one-step reduction method has excellent performance in removal of dyes in water.展开更多
基金financial supports from the National Natural Science Foundation of China(No.51373137)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2017JQ2002)+3 种基金the International Cooperation Project of Shaanxi Province(No.2016KW-053)the Fundamental Research Funds for the Central Universities(No.3102018zy047)the Graduate Starting Seed Fund of Northwestern Polytechnical University(No.ZZ2018195)Shanghai space science and technology innovation fund。
文摘Advanced oxidation processes are widely applied to removal of persistent toxic substances from wastewater by hydroxyl radicals(·OH),which is generated from hydrogen peroxide(H2O2)decomposition.However,their practical applications have been hampered by many strict conditions,such as iron sludge,rigid pH condition,large doses of hydrogen peroxide and Fe^2+,etc.Herein,a magnetically recyclable Fe3O4@polydopamine(Fe3O4@PDA)coreshell nanocomposite was fabricated.As an excellent reducing agent,it can convert Fe^3+to Fe^2+.Combined with the coordination of polydopamine and ferric ions,the production of iron sludge is inhibited.The minimum concentration of hydrogen peroxide(0.2 mmol/L and Fe^2+(0.18 mmol/L))is 150-fold and 100-fold lower than that of previous reports,respectively.It also exhibits excellent degradation performance over a wide pH range from 3.0 to 9.0.Even after the tenth recycling,it still achieves over 99%degradation efficiency with the total organic carbon degradation rate of 80%,which is environmentally benign and has a large economic advantage.This discovery paves a way for extensive practical application of advanced oxidation processes,especially in environmental remediation.
基金supported by the Fundamental Research Funds for Central Universities and Research Funds of Renmin University of China(Nos.14XLNQ02,15XNLD04)
文摘Magnetic Fe^0/Fe3O4/graphene has been successfully synthesized by a one-step reduction method and investigated in rapid degradation of dyes in this work. The material was characterized by N2 sorption–desorption, scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FT-IR）, vibrating-sample magnetometer（VSM） measurements and X-ray photoelectron spectroscopy（XPS）. The results indicated that Fe^0/Fe3O4/graphene had a layered structure with Fe crystals highly dispersed in the interlayers of graphene, which could enhance the mass transfer process between Fe^0/Fe3O4/graphene and pollutants. Fe^0/Fe3O4/graphene exhibited ferromagnetism and could be easily separated and re-dispersed for reuse in water. Typical dyes, such as Methyl Orange, Methylene Blue and Crystal Violet, could be decolorized by Fe^0/Fe3O4/graphene rapidly. After 20 min, the decolorization efficiencies of methyl orange, methylene blue and crystal violet were 94.78%, 91.60% and 89.07%, respectively. The reaction mechanism of Fe^0/Fe3O4/graphene with dyes mainly included adsorption and enhanced reduction by the composite. Thus, Fe^0/Fe3O4/graphene prepared by the one-step reduction method has excellent performance in removal of dyes in water.
