This study demonstrated interesting ultrafast activation of molecular O_(2) by copper oxide(CuO)particles and very rapid elimination of aqueous 2,4-dichlo rophenol(2,4-DCP)within reaction time of 30 s.Electron paramag...This study demonstrated interesting ultrafast activation of molecular O_(2) by copper oxide(CuO)particles and very rapid elimination of aqueous 2,4-dichlo rophenol(2,4-DCP)within reaction time of 30 s.Electron paramagnetic resonance(EPR)characterization indicated that·OH,Cu^(3+),^1 O_(2) and O_(2)^·-were generated in the CuO/O_(2) systems,wherein O_(2)^·-would be the main reactive species responsible for 2,4-DCP degradation.It was further found that the catalytic ability of CuO for O_(2) activation was highly size dependent and nano-CuO was far reactive than micro-CuO.H2 temperature-programmed reduction(H2-TPR),X-ray photoelectron spectroscopy(XPS)and vibrating sample magnetometer(VSM)analyses revealed that both the quantity and the reactivity of the surface reaction sites(surface Cu+and O_(2))could determine the catalytic ability of CuO affecting efficient Cu^(+)-based molecular oxygen activation.Moreover,the O_(2) activation ability of CuO would depend on not only the dimension,but also crystalline factors,for example,the exposed facets.展开更多
This study has demonstrated an interesting amplification effect of magnetic field (MF) on the hydroxylamine (HA)-promoted zero valent iron (ZVI)/H_(2)O_(2) Fenton-like system. Sulfamethoxazole (SMX) could be efficient...This study has demonstrated an interesting amplification effect of magnetic field (MF) on the hydroxylamine (HA)-promoted zero valent iron (ZVI)/H_(2)O_(2) Fenton-like system. Sulfamethoxazole (SMX) could be efficiently degraded at near neutral pH. Conditional parameters affecting the SMX degradation in the ZVI/H_(2)O_(2)/HA/MF system, e.g., pH and the dosages of ZVI, HA and H_(2)O_(2), were investigated. Unlike the acid-favorable ZVI/H_(2)O_(2) and ZVI/H_(2)O_(2)/HA systems, the MF-assisted system exhibited good performances even at pH up to 6.0 and highest degradation rate at pH of 5.0. ^(·)OH was still identified as the responsible oxidant. A mechanism involving the MF-enhanced heterogeneous-homogeneous iron cycle was proposed in the near-neutral ZVI/H_(2)O_(2)/HA system. Without MF, HA-induced reductive dissolution of the surface iron oxides occurred and thus leaded to homogeneous Fenton reactions. After the introduction of MF, the gradient magnetic field formed on the ZVI particles would induce the generation of concentration cells of Fe(II) and local corrosion of iron. Large amounts of aqueous and bounded Fe(II) catalyzed H_(2)O_(2) to efficiently produce ^(·)OH, while HA maintained the surface and bulk cycles of Fe(II)/Fe(III). The result of study is expected to provide a green, energy-free method in improving the effectiveness of ZVI-based Fenton-like technologies at weak-acidic circumstances.展开更多
This study demonstrated that as-synthesized nano Fe/Cu bimetals could achieve significant enhancement in the degradation of diclofenac(DCF),as compared to much slow removal of DCF by Cu(Ⅱ) or zero valent iron nanopar...This study demonstrated that as-synthesized nano Fe/Cu bimetals could achieve significant enhancement in the degradation of diclofenac(DCF),as compared to much slow removal of DCF by Cu(Ⅱ) or zero valent iron nanoparticles(nZVI),respectively.Further observations on the evolution of O_(2) activation process by nano Fe/Cu bimetals was conducted stretching to the preparation phase(started by nZVI/Cu2+).Interesting breakpoints we re observed with obvious sudden increase in the DCF degradation efficiency and decrease in solution pH,as the original nZVI just consumed up to Fe(Ⅱ) and Cu(II) appeared again.It suggested that the four-electrons reaction of O_(2) and Cu-deposited nZVI would occur to generate water prior to the breakpoints,while Cu(0) and Fe(Ⅱ) would play most important role in activation of O_(2) afterwards.Through the electron spin resonance(ESR) analysis and quenching experiments.·OH was identified as the responsible reactive species.Further time-dependent quantifications in the cases of Cu(0)/Fe(Ⅱ) systems we re carried out.It was found that the ’OH accumulation was positively and linearly correlated with nCu dose,Fe(Ⅱ) consumption,and Fe(II) dose,respectively.Since either Cu(O) or Fe(Ⅱ)would be inefficient in activating oxygen to produce ·OH,a stage-evolution mechanism of O_(2) activated by nano Fe/Cu bimetals was proposed involving:(a) Rapid consumption of Fe(0) and release of Fe(Ⅱ) based on the Cu-Fe galvanic corrosion,(b) adsorption and transformation of O_(2) to O_(2)2 at the nCu surface,and(c) Fe(Ⅱ)-catalyzed activation of the adsorbed O_(2)2 to ·OH.展开更多
基金the National Natural Science Foundation of China(Nos.21677055 and 21407052)National Key Research and Development Program of China(2019YFC1805204)+1 种基金Project of Three Gorges Corporation(No.JDZC-FW-20-001)the Fundamental Research Funds for the Central Universities,HUST(Nos.2017KFXKJC004 and2016YXMS287)。
文摘This study demonstrated interesting ultrafast activation of molecular O_(2) by copper oxide(CuO)particles and very rapid elimination of aqueous 2,4-dichlo rophenol(2,4-DCP)within reaction time of 30 s.Electron paramagnetic resonance(EPR)characterization indicated that·OH,Cu^(3+),^1 O_(2) and O_(2)^·-were generated in the CuO/O_(2) systems,wherein O_(2)^·-would be the main reactive species responsible for 2,4-DCP degradation.It was further found that the catalytic ability of CuO for O_(2) activation was highly size dependent and nano-CuO was far reactive than micro-CuO.H2 temperature-programmed reduction(H2-TPR),X-ray photoelectron spectroscopy(XPS)and vibrating sample magnetometer(VSM)analyses revealed that both the quantity and the reactivity of the surface reaction sites(surface Cu+and O_(2))could determine the catalytic ability of CuO affecting efficient Cu^(+)-based molecular oxygen activation.Moreover,the O_(2) activation ability of CuO would depend on not only the dimension,but also crystalline factors,for example,the exposed facets.
基金supported by the National Natural Science Foundation of China (Nos. 21677055 and 22006045)the China Postdoctory Science Foundation (No. 2020M672361)the Project of Three Gorges Corporation (No. JD-ZC-FW-20-001)。
文摘This study has demonstrated an interesting amplification effect of magnetic field (MF) on the hydroxylamine (HA)-promoted zero valent iron (ZVI)/H_(2)O_(2) Fenton-like system. Sulfamethoxazole (SMX) could be efficiently degraded at near neutral pH. Conditional parameters affecting the SMX degradation in the ZVI/H_(2)O_(2)/HA/MF system, e.g., pH and the dosages of ZVI, HA and H_(2)O_(2), were investigated. Unlike the acid-favorable ZVI/H_(2)O_(2) and ZVI/H_(2)O_(2)/HA systems, the MF-assisted system exhibited good performances even at pH up to 6.0 and highest degradation rate at pH of 5.0. ^(·)OH was still identified as the responsible oxidant. A mechanism involving the MF-enhanced heterogeneous-homogeneous iron cycle was proposed in the near-neutral ZVI/H_(2)O_(2)/HA system. Without MF, HA-induced reductive dissolution of the surface iron oxides occurred and thus leaded to homogeneous Fenton reactions. After the introduction of MF, the gradient magnetic field formed on the ZVI particles would induce the generation of concentration cells of Fe(II) and local corrosion of iron. Large amounts of aqueous and bounded Fe(II) catalyzed H_(2)O_(2) to efficiently produce ^(·)OH, while HA maintained the surface and bulk cycles of Fe(II)/Fe(III). The result of study is expected to provide a green, energy-free method in improving the effectiveness of ZVI-based Fenton-like technologies at weak-acidic circumstances.
基金the National Natural Science Foundation of China(Nos.21677055 and 21407052)National Key Research and Development Program of China(No.2019YFC1805204)+1 种基金Project of Three Gorges Corporation(No.JDZC-FW-20-001)the Fundamental Research Funds for the Central Universities,HUST(No.2017KFXKJC004)。
文摘This study demonstrated that as-synthesized nano Fe/Cu bimetals could achieve significant enhancement in the degradation of diclofenac(DCF),as compared to much slow removal of DCF by Cu(Ⅱ) or zero valent iron nanoparticles(nZVI),respectively.Further observations on the evolution of O_(2) activation process by nano Fe/Cu bimetals was conducted stretching to the preparation phase(started by nZVI/Cu2+).Interesting breakpoints we re observed with obvious sudden increase in the DCF degradation efficiency and decrease in solution pH,as the original nZVI just consumed up to Fe(Ⅱ) and Cu(II) appeared again.It suggested that the four-electrons reaction of O_(2) and Cu-deposited nZVI would occur to generate water prior to the breakpoints,while Cu(0) and Fe(Ⅱ) would play most important role in activation of O_(2) afterwards.Through the electron spin resonance(ESR) analysis and quenching experiments.·OH was identified as the responsible reactive species.Further time-dependent quantifications in the cases of Cu(0)/Fe(Ⅱ) systems we re carried out.It was found that the ’OH accumulation was positively and linearly correlated with nCu dose,Fe(Ⅱ) consumption,and Fe(II) dose,respectively.Since either Cu(O) or Fe(Ⅱ)would be inefficient in activating oxygen to produce ·OH,a stage-evolution mechanism of O_(2) activated by nano Fe/Cu bimetals was proposed involving:(a) Rapid consumption of Fe(0) and release of Fe(Ⅱ) based on the Cu-Fe galvanic corrosion,(b) adsorption and transformation of O_(2) to O_(2)2 at the nCu surface,and(c) Fe(Ⅱ)-catalyzed activation of the adsorbed O_(2)2 to ·OH.
