The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. ...The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. The molar ratio of Fe and Mn in the synthetic Fe-Mn binary oxides was 4 ： 3. The FM-1 and FM-2（prepared at different activation temperatures） having high specific surface areas（358.87 and 128.58 m^2/g, respectively） were amorphous and of nano particle types. The amount of arsenic adsorbed on FM-1 was higher than that adsorbed on FM-2 particles. After adsorption by FM-1, residual arsenic concentration decreased to less than 10 μg/L. The adsorption kinetics data were analyzed using different kinetic models including pseudo first-order model, pseudo second-order model, Elovich model and intraparticle diffusion model. Pseudo second-order kinetic model was the most appropriate model to describe the adsorption kinetics. The adsorption percentage of As（Ⅲ） increased in the p H range of 2–3 while it decreased with the increase of pH（ 3〈pH〈10）. The effects of coexisting anions on As（Ⅲ） removal using FM-1 and FM-2 were also studied and the order of the effects is as follows： NO_3^-, Cl-, F-〈SO_4^（2-）, HCO_3-〈H_2PO_4^-, indicating that H_2PO_4^- is the major competitor with As（Ⅲ） for adsorptive sites on the surface of the adsorbents. The higher adsorption capacity of FM-1 makes it potentially attractive adsorbent for the removal of As（Ⅲ） from groundwater.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
Photocatalytic oxidation kinetics of thiophene in n-octane/water extraction system was studied with fluorine and ferric ion codoped nano-TiO_2(nano-F^-/Fe^(3+)/TiO_2) powders used as the photocatalyst.Effects of initi...Photocatalytic oxidation kinetics of thiophene in n-octane/water extraction system was studied with fluorine and ferric ion codoped nano-TiO_2(nano-F^-/Fe^(3+)/TiO_2) powders used as the photocatalyst.Effects of initial concentration of thiophene and additional dosage of F^-/Fe^(3+)/TiO_2 on the reaction rate constant and half-life were investigated.The results showed that the appropriately added dosage of F^-/Fe^(3+)/TiO_2 was 0.1 g in the 100-mL reaction system and the photooxidative kinetics of thiophene in the presence of F^-/Fe^(3+)/TiO_2 catalyst was of first-order with a rate constant of 0.6508 h^(-1) and a half-life of 1.0651 h.The desulfurization rate of thiophene was 98.1%in 5 h and the sulfur content could be reduced from 800 ppm to 15 ppm.The reaction rate constant increased with a decreasing initial concentration of thiophene.展开更多
Chlorinated hydrocarbons are widely detected in groundwater, but conventional removal methodologies are not time-and-cost effective. With the development of iron reducing technology in recent years, research on nano-i...Chlorinated hydrocarbons are widely detected in groundwater, but conventional removal methodologies are not time-and-cost effective. With the development of iron reducing technology in recent years, research on nano-iron and nano-bimetal has become a hot spot. The paper presents the results of impact factors on perchloroethylene （PCE） removal by nano-Ni/Fe method. The data show that the reaction rate of unexposed nano-Ni/Fe is 4 times higher than exposed one; and temperature is one of the important controlling factors. Reaction rate constant KSA increases by 2-3 times with every 10℃ increment of temperature. Within a specific range, higher Ni/Fe ratio favors dechlorination process. When the Ni/Fe is 8%, the dechlorination process reaches the highest rate. Dissoved oxygen in the solution does not favor the degradation of chlorinated hydrocarbons.展开更多
Nano-F-/Fe3+/TiO2 particles were prepared by hydrolysis of tetrabutyl titanate in a mixed CF3COOH-Fe(NO3)3-H2O solution. The photocatalytic decomposition of methylene blue in aqueous solution was used as a probe to ev...Nano-F-/Fe3+/TiO2 particles were prepared by hydrolysis of tetrabutyl titanate in a mixed CF3COOH-Fe(NO3)3-H2O solution. The photocatalytic decomposition of methylene blue in aqueous solution was used as a probe to evaluate their photocatalytic activities. The powders were characterized by X-ray diffraction(XRD),energy dispersion X-ray spectrum(EDS) and Brunauer-Emmett-Teller(BET) surface area analysis. The results show that F-and Fe 3+ are doped into TiO2. The F-and Fe3+ doping can help to enhance the nano-TiO2 photocatalytic activity greatly. The appropriate codoping conditions for F-Fe are n(F)/n(TiO2)=2%,n(Fe)/n(TiO2)=0.05%,and the degradation rate of methylene blue at 1 h is improved from 73.2% to 87.5%. The codoped nano-F-/Fe3+/TiO2 particles have higher BET specific surface area,smaller crystallite size and higher photocatalytic activity than those of undoped TiO2 particles.展开更多
One of the primary features of nano-indentation technique is that the contact area induced by an indenter is indirectly measured by a relationship between the penetration depth and the known geometry of the indenter.H...One of the primary features of nano-indentation technique is that the contact area induced by an indenter is indirectly measured by a relationship between the penetration depth and the known geometry of the indenter.However,this indirect measurement occasionally leads to inaccurate properties of the indented material.The objective of this study is to investigate the effects of E/σr and the strain hardening exponents n of materials on the behaviors of pile-up and sink-in in nano-indentation and to predict n values of materials from the residual indentation impressions.The relations between the residual indentation profile and n value of the indented material were identified by dimensional analysis.Also,they were numerically formulated using FE analysis of nano-indentation for 140 different combinations of elastic-plastic parameters such as E,σy and n.The parameters of hrp/hm,herp/hm,Rr/hm and HO&P/Hreal were introduced as various dimensionless parameters to represent and quantify the residual indentation profile after indentation.They were subsequently characterized as dimensionless functions using n and E/σr values.Finally,the validity of these functions was verified through 3D FE analysis of nano-indentation for Al 6061-T6 and AISI 1010 materials.展开更多
Fe-Cu thin films of 0.2 mum in thickness with different Cu contents wereprepared by using r.f. magnetron sputtering onto glass substrate. The effect of sputteringparameters, including Ar gas pressure and input rf powe...Fe-Cu thin films of 0.2 mum in thickness with different Cu contents wereprepared by using r.f. magnetron sputtering onto glass substrate. The effect of sputteringparameters, including Ar gas pressure and input rf power, on the structure and magnetic propertieswas investigated. It was found that when the power is lower than 70W, the structure of the filmsremained single bcc-Fe phase with Cu solubility of up to 50at. percent. TEM observations for thebcc-Fe phase showed that the grain size was in the nanometer range of less than 20nm. The coercivityof Fe- Cu films was largely affected by not only Ar gas pressure but also rf power, and reachedabout 2.5Oe in the pressure of 0.67-6.67Pa and in the power of less than 100W. In addition,saturation magnetization, with Cu content less than 60at. percent, was about proportional to thecontent of bcc-Fe. When Cu content was at 60at. percent, however, saturation magnetization was muchsmaller than its calculation value.展开更多
基金supported by the National Natural Science Foundation of China(No.41120124003)the Ministry of Science and Technology of China(No.2012AA062602)the 111 project and Priority Development Projects of SRFDP of the Ministry of Education of China
文摘The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. The molar ratio of Fe and Mn in the synthetic Fe-Mn binary oxides was 4 ： 3. The FM-1 and FM-2（prepared at different activation temperatures） having high specific surface areas（358.87 and 128.58 m^2/g, respectively） were amorphous and of nano particle types. The amount of arsenic adsorbed on FM-1 was higher than that adsorbed on FM-2 particles. After adsorption by FM-1, residual arsenic concentration decreased to less than 10 μg/L. The adsorption kinetics data were analyzed using different kinetic models including pseudo first-order model, pseudo second-order model, Elovich model and intraparticle diffusion model. Pseudo second-order kinetic model was the most appropriate model to describe the adsorption kinetics. The adsorption percentage of As（Ⅲ） increased in the p H range of 2–3 while it decreased with the increase of pH（ 3〈pH〈10）. The effects of coexisting anions on As（Ⅲ） removal using FM-1 and FM-2 were also studied and the order of the effects is as follows： NO_3^-, Cl-, F-〈SO_4^（2-）, HCO_3-〈H_2PO_4^-, indicating that H_2PO_4^- is the major competitor with As（Ⅲ） for adsorptive sites on the surface of the adsorbents. The higher adsorption capacity of FM-1 makes it potentially attractive adsorbent for the removal of As（Ⅲ） from groundwater.
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.
文摘Photocatalytic oxidation kinetics of thiophene in n-octane/water extraction system was studied with fluorine and ferric ion codoped nano-TiO_2(nano-F^-/Fe^(3+)/TiO_2) powders used as the photocatalyst.Effects of initial concentration of thiophene and additional dosage of F^-/Fe^(3+)/TiO_2 on the reaction rate constant and half-life were investigated.The results showed that the appropriately added dosage of F^-/Fe^(3+)/TiO_2 was 0.1 g in the 100-mL reaction system and the photooxidative kinetics of thiophene in the presence of F^-/Fe^(3+)/TiO_2 catalyst was of first-order with a rate constant of 0.6508 h^(-1) and a half-life of 1.0651 h.The desulfurization rate of thiophene was 98.1%in 5 h and the sulfur content could be reduced from 800 ppm to 15 ppm.The reaction rate constant increased with a decreasing initial concentration of thiophene.
基金the National Natural Science Foundation of China （40572146） the project （2002BA906A28-1B） from the Ministry of Science and Technology of China.
文摘Chlorinated hydrocarbons are widely detected in groundwater, but conventional removal methodologies are not time-and-cost effective. With the development of iron reducing technology in recent years, research on nano-iron and nano-bimetal has become a hot spot. The paper presents the results of impact factors on perchloroethylene （PCE） removal by nano-Ni/Fe method. The data show that the reaction rate of unexposed nano-Ni/Fe is 4 times higher than exposed one; and temperature is one of the important controlling factors. Reaction rate constant KSA increases by 2-3 times with every 10℃ increment of temperature. Within a specific range, higher Ni/Fe ratio favors dechlorination process. When the Ni/Fe is 8%, the dechlorination process reaches the highest rate. Dissoved oxygen in the solution does not favor the degradation of chlorinated hydrocarbons.
基金Project(203364) supported by the Natural Science Foundation of Hebei Province, Chinaproject(XL2006038) supported by the Natural Science Foundation of Hebei University of Science and Technology, China
文摘Nano-F-/Fe3+/TiO2 particles were prepared by hydrolysis of tetrabutyl titanate in a mixed CF3COOH-Fe(NO3)3-H2O solution. The photocatalytic decomposition of methylene blue in aqueous solution was used as a probe to evaluate their photocatalytic activities. The powders were characterized by X-ray diffraction(XRD),energy dispersion X-ray spectrum(EDS) and Brunauer-Emmett-Teller(BET) surface area analysis. The results show that F-and Fe 3+ are doped into TiO2. The F-and Fe3+ doping can help to enhance the nano-TiO2 photocatalytic activity greatly. The appropriate codoping conditions for F-Fe are n(F)/n(TiO2)=2%,n(Fe)/n(TiO2)=0.05%,and the degradation rate of methylene blue at 1 h is improved from 73.2% to 87.5%. The codoped nano-F-/Fe3+/TiO2 particles have higher BET specific surface area,smaller crystallite size and higher photocatalytic activity than those of undoped TiO2 particles.
基金Project(2010-0008-277)supported by the NCRC(National Core Research Center)Program through the National Research Foundation of Koreafunded by the Ministry of Education,Science,and Technology,KoreaProject supported by R&D for Technology Development Program of Ministry of Knowledge Economy,Korea
文摘One of the primary features of nano-indentation technique is that the contact area induced by an indenter is indirectly measured by a relationship between the penetration depth and the known geometry of the indenter.However,this indirect measurement occasionally leads to inaccurate properties of the indented material.The objective of this study is to investigate the effects of E/σr and the strain hardening exponents n of materials on the behaviors of pile-up and sink-in in nano-indentation and to predict n values of materials from the residual indentation impressions.The relations between the residual indentation profile and n value of the indented material were identified by dimensional analysis.Also,they were numerically formulated using FE analysis of nano-indentation for 140 different combinations of elastic-plastic parameters such as E,σy and n.The parameters of hrp/hm,herp/hm,Rr/hm and HO&P/Hreal were introduced as various dimensionless parameters to represent and quantify the residual indentation profile after indentation.They were subsequently characterized as dimensionless functions using n and E/σr values.Finally,the validity of these functions was verified through 3D FE analysis of nano-indentation for Al 6061-T6 and AISI 1010 materials.
基金This research is sponsored by the National Natural Science Foundation of China (Grant No.69971006).
文摘Fe-Cu thin films of 0.2 mum in thickness with different Cu contents wereprepared by using r.f. magnetron sputtering onto glass substrate. The effect of sputteringparameters, including Ar gas pressure and input rf power, on the structure and magnetic propertieswas investigated. It was found that when the power is lower than 70W, the structure of the filmsremained single bcc-Fe phase with Cu solubility of up to 50at. percent. TEM observations for thebcc-Fe phase showed that the grain size was in the nanometer range of less than 20nm. The coercivityof Fe- Cu films was largely affected by not only Ar gas pressure but also rf power, and reachedabout 2.5Oe in the pressure of 0.67-6.67Pa and in the power of less than 100W. In addition,saturation magnetization, with Cu content less than 60at. percent, was about proportional to thecontent of bcc-Fe. When Cu content was at 60at. percent, however, saturation magnetization was muchsmaller than its calculation value.
