This study investigates how large-surface-area biocarbons with high phenolic adsorption capacities can be obtained from cheap and abundant rice husk(RH).The RH is directly mixed with potassium hydroxide(KOH)and activa...This study investigates how large-surface-area biocarbons with high phenolic adsorption capacities can be obtained from cheap and abundant rice husk(RH).The RH is directly mixed with potassium hydroxide(KOH)and activated in a flowing N_(2) atmosphere,and the effects of the pyrolysis temperature and KOH to RH ratio on the structure of the obtained activated carbon adsorbents and their adsorption of p-nitrophenol and phenol are studied.The results show that the optimum pyrolysis temperature of RH is 750℃,whereby the highest surface area of 2047 m^(2)/g and best adsorption performance are obtained with a KOH to RH ratio of 3:1.Moreover,the obtained biocarbons achieve a maximum adsorption capacity of 175 mg/g for phenol and 430 mg/g for p-nitrophenol,which are higher than most previously reported data.展开更多
研究目的:针对目前减振轨道减振效果现场测试评价中忽略地层因素影响的研究现状,本文通过现场测试量化地层差异对轨道减振效果评价的影响,提出具有显著影响的地层因素及规律,明确不同地层参照断面选取对测试结果的影响程度。研究结论:(1...研究目的:针对目前减振轨道减振效果现场测试评价中忽略地层因素影响的研究现状,本文通过现场测试量化地层差异对轨道减振效果评价的影响,提出具有显著影响的地层因素及规律,明确不同地层参照断面选取对测试结果的影响程度。研究结论:(1)本测试研究结果表明选取不同断面测试分析隧道壁对比损失时,地层差异能引起隧道壁分频振级对比损失结果最大相差10 d B以上,Z振级对比损失结果相差4 d B以上;(2)隧道壁壁后地层剪切波速和波阻抗对隧道壁对比损失影响较大,土体波阻抗为1.5~2倍关系时,隧道壁对比损失最大Z振级差值可超过3 d B;(3)地层剪切波速随深度增加时,对比工况埋深越浅,测试得到的隧道壁对比损失越大,获得的减振效果越好;(4)本研究成果可为减振轨道设计、工后评价提供参考和指导。展开更多
A Microbial fuel cell(MFC)with metal free polymer/graphite electrodes(150 mm×150 mm)was constructed.The electrodes with flowing channels,which were different in roughness,were designed.No additional catalyst was ...A Microbial fuel cell(MFC)with metal free polymer/graphite electrodes(150 mm×150 mm)was constructed.The electrodes with flowing channels,which were different in roughness,were designed.No additional catalyst was coated on the electrode,therefore the MFC was cheaper and possessed good durability with high performance.The effect of roughness,K3Fe(CN)6 concentration and sprayed air on the performance of the constructed MFC was investigated.Results showed that the roughness of electrode can significantly affect the performance of MFC.The power density of MFC increased by 1.56 times owing to the arithmetic mean roughness which has increased by 1.41 times.With an increasing K3Fe(CN)6 concentration,the performance of MFC also improves.The MFC with K3Fe(CN)6 only(30 mM)showed the highest power density of 1260 mW/m2,which is by 21.4 times and 1.3 times higher than those of MFCs with spraying air only(59 mW/m2)and with K3Fe(CN)6+air(1005 mW/m2),respectively.This showed that the appropriate concentration of K3Fe(CN)6 can significantly improve the power density,while the air has a negative effect when it is sprayed onto K3Fe(CN)6 catholyte.A coulombic efficiency of 34.2%and an energy efficiency of 13.3%with a COD degradation rate of 73.5%were achieved with MFC using K3Fe(CN)6 only.The overpotentials of MFC were also calculated.It can be seen that both theηohmic andηconcentration were very low as compared to theηactivation,and theηconcentration can be ignored because its effect was less than 3 mV.The theoretical calculation suggested that with an increasing conversion rate of K3Fe(CN)6,the cathode potential decreased and reached 0.31 V at a conversion rate of 0.99.While the anode behaves differently for constant pH and changeable pH as the reaction progresses,which reveals that the buffer solution and removal of protons play an important role in maintaining the anode potential.展开更多
A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-...A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-rods(NRs)were prepared by growing them directly on carbon cloth(CC)via a simple hydrothermal reaction coupled with an annealing treatment.The resulting NiMoO_(4)-NR/CC-x composites served directly as electrodes for electrolysis of an alkaline medium and a simulated sea water.The results indicated that among the NiMoO_(4)-NR/CC-x composites,the NiMoO_(4)-NR/CC-10 composite possessed the highest HER activity with an overpotential of 244.8 mV at 10 mA/cm^(2),a Tafel slope of 95 mV/dec,the fastest charge transfer rate(R_(ct)<1Ω)and good stability in alkaline media.Even in simulated seawater,the NiMoO_(4)-NR/CC-10 composite showed good stability.The outstanding HER activity and stability may originate from the strong interaction between Ni and Mo in the NiMoO_(4) NRs as well as the efficient charge transfer process and the rate of the HER due to the synergistic effect involving the CC and NiMoO_(4) NRs.展开更多
Nickel phosphide-carbon-doped alumina(Ni_(2)P/Al_(2)O_(3)-C)catalysts with 10 wt.%Ni_(2)P loading were successfully prepared via a hydrothermal reduction process and the effect of reduction temperature on the hydrodes...Nickel phosphide-carbon-doped alumina(Ni_(2)P/Al_(2)O_(3)-C)catalysts with 10 wt.%Ni_(2)P loading were successfully prepared via a hydrothermal reduction process and the effect of reduction temperature on the hydrodesulfurization(HDS)performance of the as-prepared Ni_(2)P/Al_(2)O_(3)-C catalysts was investigated.The properties of the support(Al_(2)O_(3)-C)and Ni_(2)P/Al_(2)O_(3)-C catalysts were characterized by transmission electron microscopy,scanning electron microscopy,Brunauer-Emmett-Teller measurements,X-ray diffractometry,and X-ray photoelectron spectroscopy.The results indicated that the incorporation of carbon in the support aided the reduction of Ni_(2)P.With an increase in the reduction temperature,Ni and Ni_(12)P_(5) were first generated and then converted into crystalline Ni_(2)P.Furthermore,a higher reduction temperature enhanced the HDS performance of the catalyst by generating more well-dispersed active-phase crystalline Ni_(2)P.展开更多
文摘This study investigates how large-surface-area biocarbons with high phenolic adsorption capacities can be obtained from cheap and abundant rice husk(RH).The RH is directly mixed with potassium hydroxide(KOH)and activated in a flowing N_(2) atmosphere,and the effects of the pyrolysis temperature and KOH to RH ratio on the structure of the obtained activated carbon adsorbents and their adsorption of p-nitrophenol and phenol are studied.The results show that the optimum pyrolysis temperature of RH is 750℃,whereby the highest surface area of 2047 m^(2)/g and best adsorption performance are obtained with a KOH to RH ratio of 3:1.Moreover,the obtained biocarbons achieve a maximum adsorption capacity of 175 mg/g for phenol and 430 mg/g for p-nitrophenol,which are higher than most previously reported data.
文摘研究目的:针对目前减振轨道减振效果现场测试评价中忽略地层因素影响的研究现状,本文通过现场测试量化地层差异对轨道减振效果评价的影响,提出具有显著影响的地层因素及规律,明确不同地层参照断面选取对测试结果的影响程度。研究结论:(1)本测试研究结果表明选取不同断面测试分析隧道壁对比损失时,地层差异能引起隧道壁分频振级对比损失结果最大相差10 d B以上,Z振级对比损失结果相差4 d B以上;(2)隧道壁壁后地层剪切波速和波阻抗对隧道壁对比损失影响较大,土体波阻抗为1.5~2倍关系时,隧道壁对比损失最大Z振级差值可超过3 d B;(3)地层剪切波速随深度增加时,对比工况埋深越浅,测试得到的隧道壁对比损失越大,获得的减振效果越好;(4)本研究成果可为减振轨道设计、工后评价提供参考和指导。
基金The authors would like to thank the Federal Ministry of Education and Research(Bundesministerium für Bildung und Forschung),BMBF,Germany,for funding parts of this study under the contract No.02WER1317D.
文摘A Microbial fuel cell(MFC)with metal free polymer/graphite electrodes(150 mm×150 mm)was constructed.The electrodes with flowing channels,which were different in roughness,were designed.No additional catalyst was coated on the electrode,therefore the MFC was cheaper and possessed good durability with high performance.The effect of roughness,K3Fe(CN)6 concentration and sprayed air on the performance of the constructed MFC was investigated.Results showed that the roughness of electrode can significantly affect the performance of MFC.The power density of MFC increased by 1.56 times owing to the arithmetic mean roughness which has increased by 1.41 times.With an increasing K3Fe(CN)6 concentration,the performance of MFC also improves.The MFC with K3Fe(CN)6 only(30 mM)showed the highest power density of 1260 mW/m2,which is by 21.4 times and 1.3 times higher than those of MFCs with spraying air only(59 mW/m2)and with K3Fe(CN)6+air(1005 mW/m2),respectively.This showed that the appropriate concentration of K3Fe(CN)6 can significantly improve the power density,while the air has a negative effect when it is sprayed onto K3Fe(CN)6 catholyte.A coulombic efficiency of 34.2%and an energy efficiency of 13.3%with a COD degradation rate of 73.5%were achieved with MFC using K3Fe(CN)6 only.The overpotentials of MFC were also calculated.It can be seen that both theηohmic andηconcentration were very low as compared to theηactivation,and theηconcentration can be ignored because its effect was less than 3 mV.The theoretical calculation suggested that with an increasing conversion rate of K3Fe(CN)6,the cathode potential decreased and reached 0.31 V at a conversion rate of 0.99.While the anode behaves differently for constant pH and changeable pH as the reaction progresses,which reveals that the buffer solution and removal of protons play an important role in maintaining the anode potential.
文摘A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-rods(NRs)were prepared by growing them directly on carbon cloth(CC)via a simple hydrothermal reaction coupled with an annealing treatment.The resulting NiMoO_(4)-NR/CC-x composites served directly as electrodes for electrolysis of an alkaline medium and a simulated sea water.The results indicated that among the NiMoO_(4)-NR/CC-x composites,the NiMoO_(4)-NR/CC-10 composite possessed the highest HER activity with an overpotential of 244.8 mV at 10 mA/cm^(2),a Tafel slope of 95 mV/dec,the fastest charge transfer rate(R_(ct)<1Ω)and good stability in alkaline media.Even in simulated seawater,the NiMoO_(4)-NR/CC-10 composite showed good stability.The outstanding HER activity and stability may originate from the strong interaction between Ni and Mo in the NiMoO_(4) NRs as well as the efficient charge transfer process and the rate of the HER due to the synergistic effect involving the CC and NiMoO_(4) NRs.
基金supported by the National Natural Science Foundation of China (22008134)
文摘Nickel phosphide-carbon-doped alumina(Ni_(2)P/Al_(2)O_(3)-C)catalysts with 10 wt.%Ni_(2)P loading were successfully prepared via a hydrothermal reduction process and the effect of reduction temperature on the hydrodesulfurization(HDS)performance of the as-prepared Ni_(2)P/Al_(2)O_(3)-C catalysts was investigated.The properties of the support(Al_(2)O_(3)-C)and Ni_(2)P/Al_(2)O_(3)-C catalysts were characterized by transmission electron microscopy,scanning electron microscopy,Brunauer-Emmett-Teller measurements,X-ray diffractometry,and X-ray photoelectron spectroscopy.The results indicated that the incorporation of carbon in the support aided the reduction of Ni_(2)P.With an increase in the reduction temperature,Ni and Ni_(12)P_(5) were first generated and then converted into crystalline Ni_(2)P.Furthermore,a higher reduction temperature enhanced the HDS performance of the catalyst by generating more well-dispersed active-phase crystalline Ni_(2)P.
