Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM ...Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM （transmission electron microscope）, XRD （X-ray diffractometer）, and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol （p-CP） as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L （Ni 5 wt%）. The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.展开更多
Hydrothermal method was used to synthesize nanoscale particles of MnZn ferrites. The crystallites were characterized by XRD, TEM and SEM. The effects of the reaction time, temperature and additives on the product were...Hydrothermal method was used to synthesize nanoscale particles of MnZn ferrites. The crystallites were characterized by XRD, TEM and SEM. The effects of the reaction time, temperature and additives on the product were investigated. Crystallization process would be carried out above 160 ℃ for 5 h or more, higher temperature can reduce the reaction time. Additives were used to remove impurities such as Fe 2O 3, ZnMnO 3.10～15 nm pure slightly agglomerated MnZn ferrite crystallites with a narrow grain size distribution were obtained.展开更多
Nanoscale zero-valent iron particles(NZVI) produced by using green tea(GT) extract as a reductant can remove Cr(Ⅵ) from water effectively,which can be utilized in groundwater remediation.In order to define the reacti...Nanoscale zero-valent iron particles(NZVI) produced by using green tea(GT) extract as a reductant can remove Cr(Ⅵ) from water effectively,which can be utilized in groundwater remediation.In order to define the reaction mechanism and removal effect in the aquifer,in this study,GT-NZVI particles were prepared and measured by some characterization methods to define their surface performance,and then batch and one-dimensional experiments were carried out to reveal the reaction properties of GT-NZVI and Cr(Ⅵ) in groundwater.The results showed that the prepared GT-NZVI particles were regular spherical with a diameter of 10-20 nm,which could disperse in water stably.The main component of GT-NZVI wasα-Fe with superficial polyphenols as a stabilizer.GT-NZVI suspension had good ability to reduce the Cr(Ⅵ) to Cr(Ⅲ) in water.When the concentration of GT-NZVI was 1 g/L,the removal efficiency of Cr(Ⅵ)with an initial concentration of 100 mg/L reached 92.8% in 1 h reaction.In column tests,GT-NZVI passed through the natural sand column successfully with an average outflow percentage of 71.2%.The simulated in-situ reaction zone(IRZ) with GT-NZVI was used to remediate Cr(Ⅵ) contaminated groundwater.The oufflow concentration of Cr(Ⅵ) kept in 0.14-0.32 mg/L corresponding to the outflow rate below 0.32%within 15 days,and the removal efficiency of Cr(Ⅵ) by IRZ with GT-NZVI decreased with the increase of aquifer medium particle size,groundwater flow rate and ionic strength.Most of Cr(Ⅲ) as reduzate was adsorbed or immobilized on the surface or in the lattice of GT-NZVI,which indicated effective immobilization for chromium.展开更多
Transformation of chlorophenols by nanoscale bimetallic particles represents one of the latest innovative technologies for environmental remediation. Nanoscale Pd/Fe bimetallic particles were synthesized in the labora...Transformation of chlorophenols by nanoscale bimetallic particles represents one of the latest innovative technologies for environmental remediation. Nanoscale Pd/Fe bimetallic particles were synthesized in the laboratory for treatment of o-chlorophenol. Most of the nanoscale particles are in the size range of 20—100 nm. BET specific surface area of the nanoscale Pd/Fe particles is 12.4 m2/g. In comparison, a commercially available Fe powder(<100 mesh) has a specific surface area of just 0\^49 m2/g. Batch experiments demonstrated that the nanoscale Pd/Fe bimetallic particles can effectively dechlorinate o-chlorophenol. Dechlorination efficiency is affected by the mass fraction of Pd in the bimetal, nanoscale Pd/Fe mass concentration and mixing intensity.展开更多
This paper examined the potential of using laboratory-synthesized nanoscale Pd/Fe bimetallic particles to dechlorinate chlorinated methanes, including dichloromethane (DCM), trichloromethane (CF) and tetrachloromethan...This paper examined the potential of using laboratory-synthesized nanoscale Pd/Fe bimetallic particles to dechlorinate chlorinated methanes, including dichloromethane (DCM), trichloromethane (CF) and tetrachloromethane (CT). Nanoscale Pd/Fe bimetallic particles were characterized in terms of surface area, morphology, size and structure. The parameters affecting the dechlorination efficiency were studied through batch experiments. Effects of Pd content, Pd/Fe addition, and the initial pH value of reaction system on the dechlorination efficiency of chlorinated methanes were determined systematically. Results show that nanoscale Pd/Fe bimetallic particles play a prominent role in the dechlorination of chlorinated methanes. The change of pH value and ferrous ion concentration during dechlorination reaction were also investigated in this study. It is found that the dechlorination efficiency of chlorinated methanes is in the order of CT>CF>DCM.展开更多
Presence of external electrical field plays a vital role in heat transfer and fluid flow phenomena. Keeping this in view present article is a numerical investigation of stagnation point flow of water based nanoparticl...Presence of external electrical field plays a vital role in heat transfer and fluid flow phenomena. Keeping this in view present article is a numerical investigation of stagnation point flow of water based nanoparticles suspended fluid under the influence of induced magnetic field. A detailed comparative analysis has been performed by considering Copper and Titanium dioxide nanoparticles. Utilization of similarity analysis leads to a simplified system of coupled nonlinear differential equations, which has been tackled numerically by means of shooting technique followed by Runge-Kutta of order 5. The solutions are computed correct up to 6 decimal places. Influence of pertinent parameters is examined for fluid flow, induced magnetic field, and temperature profile. One of the key findings includes that magnetic parameter plays a vital role in directing fluid flow and lowering temperature profile. Moreover, it is concluded that Cu-water based nanofluid high thermal conductivity contributes in enhancing heat transfer efficiently.展开更多
In this study, bimetallic nanoscale zero-valent iron particles（nZVI）, including copper/nanoscale zero-valent iron particles（Cu/nZVI） and nickel/nanoscale zero-valent iron particles（Ni/nZVI）, were synthesized by ...In this study, bimetallic nanoscale zero-valent iron particles（nZVI）, including copper/nanoscale zero-valent iron particles（Cu/nZVI） and nickel/nanoscale zero-valent iron particles（Ni/nZVI）, were synthesized by one-step liquid-phase reduction and applied for oxytetracycline（OTC） removal. The effects of contact time and initial p H on the removal efficiency were studied. The as-prepared nanoscale particles were characterized by scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS） and X-ray diffraction（XRD）. Finally, the degradation mechanisms of OTC utilizing the as-prepared nanoparticles were investigated by using X-ray photoelectron spectroscopy（XPS） and mass spectrometry（MS）. Cu/n ZVI presented remarkable ability for OTC degradation and removed71.44% of OTC（100 mg/L） in 4 hr, while only 62.34% and 31.05% of OTC was degraded by Ni/nZVI and nZVI respectively. XPS and MS analysis suggested that OTC was broken down to form small molecules by ·OH radicals generated from the corrosion of Fe0. Cu/nZVI and Ni/n ZVI have been proved to have potential as materials for application in OTC removal because of their significant degradation ability toward OTC.展开更多
基金Project supported by the National Basic Research Program (973) of China(No. 2003CB415006)the National Natural Science Foundation of China (No. 20337020)
文摘Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM （transmission electron microscope）, XRD （X-ray diffractometer）, and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol （p-CP） as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L （Ni 5 wt%）. The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.
文摘Hydrothermal method was used to synthesize nanoscale particles of MnZn ferrites. The crystallites were characterized by XRD, TEM and SEM. The effects of the reaction time, temperature and additives on the product were investigated. Crystallization process would be carried out above 160 ℃ for 5 h or more, higher temperature can reduce the reaction time. Additives were used to remove impurities such as Fe 2O 3, ZnMnO 3.10～15 nm pure slightly agglomerated MnZn ferrite crystallites with a narrow grain size distribution were obtained.
基金the Open Project Program of Hebei Province Collaborative Innovation Center for Sustainable Utilization of Water Resources and Optimization of Industrial Structure(Grants Nos.XTZX202108)the National Key Research and Development Program of China(Grants Nos.2019YFC1805300)。
文摘Nanoscale zero-valent iron particles(NZVI) produced by using green tea(GT) extract as a reductant can remove Cr(Ⅵ) from water effectively,which can be utilized in groundwater remediation.In order to define the reaction mechanism and removal effect in the aquifer,in this study,GT-NZVI particles were prepared and measured by some characterization methods to define their surface performance,and then batch and one-dimensional experiments were carried out to reveal the reaction properties of GT-NZVI and Cr(Ⅵ) in groundwater.The results showed that the prepared GT-NZVI particles were regular spherical with a diameter of 10-20 nm,which could disperse in water stably.The main component of GT-NZVI wasα-Fe with superficial polyphenols as a stabilizer.GT-NZVI suspension had good ability to reduce the Cr(Ⅵ) to Cr(Ⅲ) in water.When the concentration of GT-NZVI was 1 g/L,the removal efficiency of Cr(Ⅵ)with an initial concentration of 100 mg/L reached 92.8% in 1 h reaction.In column tests,GT-NZVI passed through the natural sand column successfully with an average outflow percentage of 71.2%.The simulated in-situ reaction zone(IRZ) with GT-NZVI was used to remediate Cr(Ⅵ) contaminated groundwater.The oufflow concentration of Cr(Ⅵ) kept in 0.14-0.32 mg/L corresponding to the outflow rate below 0.32%within 15 days,and the removal efficiency of Cr(Ⅵ) by IRZ with GT-NZVI decreased with the increase of aquifer medium particle size,groundwater flow rate and ionic strength.Most of Cr(Ⅲ) as reduzate was adsorbed or immobilized on the surface or in the lattice of GT-NZVI,which indicated effective immobilization for chromium.
文摘Transformation of chlorophenols by nanoscale bimetallic particles represents one of the latest innovative technologies for environmental remediation. Nanoscale Pd/Fe bimetallic particles were synthesized in the laboratory for treatment of o-chlorophenol. Most of the nanoscale particles are in the size range of 20—100 nm. BET specific surface area of the nanoscale Pd/Fe particles is 12.4 m2/g. In comparison, a commercially available Fe powder(<100 mesh) has a specific surface area of just 0\^49 m2/g. Batch experiments demonstrated that the nanoscale Pd/Fe bimetallic particles can effectively dechlorinate o-chlorophenol. Dechlorination efficiency is affected by the mass fraction of Pd in the bimetal, nanoscale Pd/Fe mass concentration and mixing intensity.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50978066)State Key Laboratory of Urban Water Resources and Environment (Grant No.2008DX06)
文摘This paper examined the potential of using laboratory-synthesized nanoscale Pd/Fe bimetallic particles to dechlorinate chlorinated methanes, including dichloromethane (DCM), trichloromethane (CF) and tetrachloromethane (CT). Nanoscale Pd/Fe bimetallic particles were characterized in terms of surface area, morphology, size and structure. The parameters affecting the dechlorination efficiency were studied through batch experiments. Effects of Pd content, Pd/Fe addition, and the initial pH value of reaction system on the dechlorination efficiency of chlorinated methanes were determined systematically. Results show that nanoscale Pd/Fe bimetallic particles play a prominent role in the dechlorination of chlorinated methanes. The change of pH value and ferrous ion concentration during dechlorination reaction were also investigated in this study. It is found that the dechlorination efficiency of chlorinated methanes is in the order of CT>CF>DCM.
文摘Presence of external electrical field plays a vital role in heat transfer and fluid flow phenomena. Keeping this in view present article is a numerical investigation of stagnation point flow of water based nanoparticles suspended fluid under the influence of induced magnetic field. A detailed comparative analysis has been performed by considering Copper and Titanium dioxide nanoparticles. Utilization of similarity analysis leads to a simplified system of coupled nonlinear differential equations, which has been tackled numerically by means of shooting technique followed by Runge-Kutta of order 5. The solutions are computed correct up to 6 decimal places. Influence of pertinent parameters is examined for fluid flow, induced magnetic field, and temperature profile. One of the key findings includes that magnetic parameter plays a vital role in directing fluid flow and lowering temperature profile. Moreover, it is concluded that Cu-water based nanofluid high thermal conductivity contributes in enhancing heat transfer efficiently.
基金supported by grants from Tai Shan Scholar Foundation(No.ts 201511003)
文摘In this study, bimetallic nanoscale zero-valent iron particles（nZVI）, including copper/nanoscale zero-valent iron particles（Cu/nZVI） and nickel/nanoscale zero-valent iron particles（Ni/nZVI）, were synthesized by one-step liquid-phase reduction and applied for oxytetracycline（OTC） removal. The effects of contact time and initial p H on the removal efficiency were studied. The as-prepared nanoscale particles were characterized by scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS） and X-ray diffraction（XRD）. Finally, the degradation mechanisms of OTC utilizing the as-prepared nanoparticles were investigated by using X-ray photoelectron spectroscopy（XPS） and mass spectrometry（MS）. Cu/n ZVI presented remarkable ability for OTC degradation and removed71.44% of OTC（100 mg/L） in 4 hr, while only 62.34% and 31.05% of OTC was degraded by Ni/nZVI and nZVI respectively. XPS and MS analysis suggested that OTC was broken down to form small molecules by ·OH radicals generated from the corrosion of Fe0. Cu/nZVI and Ni/n ZVI have been proved to have potential as materials for application in OTC removal because of their significant degradation ability toward OTC.
