In this study, the degradation efficiencies of zero-valent iron （ZVI） powders with different structures and components wereevaluated for methyl orange （MO）. The results show that the structure is an essential fact...In this study, the degradation efficiencies of zero-valent iron （ZVI） powders with different structures and components wereevaluated for methyl orange （MO）. The results show that the structure is an essential factor that affects degradation, andadded non-metallic elements help optimize the structure. The amorphous and balled-milled crystalline Fe7oSiloB2o hascomparative degradation efficiencies to MO with tl/2 values of 6.9 and 7.0 min, respectively. Increasing the boron contentcan create a favorable structure and promote degradation. The ball-milled crystalline Fe70B30 and Fe43.64B56.36 powdershave relatively short tl/2 values of 5.2 and 3.3 rain, respectively. The excellent properties are mainly attributed to theirheterogeneous structure with boron-doped active sites in ZVI. Composition segregation in the nanoscale range in anamorphous FeSiB alloy and small boron particles in the microscale range embedded in large iron particles prepared by ball-milling, both constitute effective galvanic cells that promote iron electron loss and therefore decompose organic chemicals.These findings may provide a new, highly efficient, low-cost commercial method for azo dye wastewater treatment usingZVI.展开更多
A nickel-based compound layer was prepared on a nickel plate by anodization in a 75 wt% H3PO4 solution containing NH4F. This layer was then treated by galvanostatic charge/discharge （GCD） until a black outer layer w...A nickel-based compound layer was prepared on a nickel plate by anodization in a 75 wt% H3PO4 solution containing NH4F. This layer was then treated by galvanostatic charge/discharge （GCD） until a black outer layer was detached, leaving behind a film on the nickel plate as a binder-free electrode material for supercapacitors. The microstructural characterization shows that the film consists of Ni（OH）2 and NiO, and no fluoride is found in the as-obtained film. Electrochemical tests demonstrate that this fluoride-free film electrode exhibits a high capacitance of 954 F·g^-1 at 7.5 A·g^-1, excellent rate capability （a 19.5 % capacitance reduction with the current density increasing to 120 A.g-1） and cycling stability. Within 3500 cycles, the specific capacitance does not decrease, but rather increases from 840 F·g^-1 to approximately 1092 F·g^-1 in the first 100 cycles at 60 A·g^-1, and remains stable until the aforementioned layer is detached.展开更多
A hydroxyapatite （HA） coating was achieved on H2O2-treated carbon/ carbon （C/C） composite through hydrothermally treating and induction heating deposited CaHPO4 coating in an ammonia solution under ultrasonic wate...A hydroxyapatite （HA） coating was achieved on H2O2-treated carbon/ carbon （C/C） composite through hydrothermally treating and induction heating deposited CaHPO4 coating in an ammonia solution under ultrasonic water bath. Then, this HA coating was placed in a NH4F solution and hydrothermally treated again to fabricate fluorinated hydroxyapatite （FHA） coatings for 24 h at 353, 373, 393 and 413 K, respectively. The structure, morphology and chemical composition of the HA and FHA coatings were characterized by SEM, XRD, EDS and FTIR, and the adhesiveness and chemical stability of these FHA coatings were examined by a scratch test and an immersion test, respectively. The results showed that the as-prepared FHA coatings contained needle-like or stripe-like crystals, different from those of the HA coating. As the fluoridation temperature rose, the adhesiveness of the FHA coating first increased from 34.8 to 40.9 N at a temperature between 353 and 393 K, and then decreased to 24.2 N at 413 K, while the dissolution rate of the FHA coating decreased steadily. The reasons for the property variation of the FHA coatings were proposed by analyzing the morphology, composition and structure of the coatings.展开更多
基金supported by the Program of Introducing Innovative Research Team in Dongguan under Contract Number 2014607109Shenzhen Science and Technology Research Grants under Contract Numbers JCYJ20160422104921235,JCYJ20160422143659258 and JCYJ20160422144751573
文摘In this study, the degradation efficiencies of zero-valent iron （ZVI） powders with different structures and components wereevaluated for methyl orange （MO）. The results show that the structure is an essential factor that affects degradation, andadded non-metallic elements help optimize the structure. The amorphous and balled-milled crystalline Fe7oSiloB2o hascomparative degradation efficiencies to MO with tl/2 values of 6.9 and 7.0 min, respectively. Increasing the boron contentcan create a favorable structure and promote degradation. The ball-milled crystalline Fe70B30 and Fe43.64B56.36 powdershave relatively short tl/2 values of 5.2 and 3.3 rain, respectively. The excellent properties are mainly attributed to theirheterogeneous structure with boron-doped active sites in ZVI. Composition segregation in the nanoscale range in anamorphous FeSiB alloy and small boron particles in the microscale range embedded in large iron particles prepared by ball-milling, both constitute effective galvanic cells that promote iron electron loss and therefore decompose organic chemicals.These findings may provide a new, highly efficient, low-cost commercial method for azo dye wastewater treatment usingZVI.
基金financially supported by the Natural Science Foundation of Guangdong Province, China (No. 2015A030313559)the Basic Research Project of Knowledge Innovation Program in Shenzhen (No. GJHS20120621155123009)the Innovation and Cultivation Program of College Students in Science and Technology of (Climbing Program) in Guangdong Province (No. 000018)
文摘A nickel-based compound layer was prepared on a nickel plate by anodization in a 75 wt% H3PO4 solution containing NH4F. This layer was then treated by galvanostatic charge/discharge （GCD） until a black outer layer was detached, leaving behind a film on the nickel plate as a binder-free electrode material for supercapacitors. The microstructural characterization shows that the film consists of Ni（OH）2 and NiO, and no fluoride is found in the as-obtained film. Electrochemical tests demonstrate that this fluoride-free film electrode exhibits a high capacitance of 954 F·g^-1 at 7.5 A·g^-1, excellent rate capability （a 19.5 % capacitance reduction with the current density increasing to 120 A.g-1） and cycling stability. Within 3500 cycles, the specific capacitance does not decrease, but rather increases from 840 F·g^-1 to approximately 1092 F·g^-1 in the first 100 cycles at 60 A·g^-1, and remains stable until the aforementioned layer is detached.
文摘A hydroxyapatite （HA） coating was achieved on H2O2-treated carbon/ carbon （C/C） composite through hydrothermally treating and induction heating deposited CaHPO4 coating in an ammonia solution under ultrasonic water bath. Then, this HA coating was placed in a NH4F solution and hydrothermally treated again to fabricate fluorinated hydroxyapatite （FHA） coatings for 24 h at 353, 373, 393 and 413 K, respectively. The structure, morphology and chemical composition of the HA and FHA coatings were characterized by SEM, XRD, EDS and FTIR, and the adhesiveness and chemical stability of these FHA coatings were examined by a scratch test and an immersion test, respectively. The results showed that the as-prepared FHA coatings contained needle-like or stripe-like crystals, different from those of the HA coating. As the fluoridation temperature rose, the adhesiveness of the FHA coating first increased from 34.8 to 40.9 N at a temperature between 353 and 393 K, and then decreased to 24.2 N at 413 K, while the dissolution rate of the FHA coating decreased steadily. The reasons for the property variation of the FHA coatings were proposed by analyzing the morphology, composition and structure of the coatings.
