The solvent extraction technology, was applied to recover Cu^2＋ and Ni^2＋ from plating wastewater.Lix984N was chosen as the extractant due to-its gooff extraction performance. The influence parame-ters were examlned...The solvent extraction technology, was applied to recover Cu^2＋ and Ni^2＋ from plating wastewater.Lix984N was chosen as the extractant due to-its gooff extraction performance. The influence parame-ters were examlned. The results show that the separation of Cu^2＋ and Ni＂ from sulphate medium can be realized by adjusting pH value with the help of Lix984N. For extracting Cu^2＋ and Ni^2＋, the optimal pH values are 4 and 10.5, and the maximal extraction percentages are 92.9% and 93.0%, respectively .With recovered Cu^2＋ and Ni^2＋ stripped in 170g.L^ -1 and 200 g.L^-1 H2SO4 medium, the stripping percentages of Cu^2＋ and Ni^2＋ are 92.9% and 93.0%, respectively. This method is simple and can be used to recover Cu^2＋ and Ni^2＋ from plating wastewater. And a flow sheet for separation of Cu^2＋ and Ni^2＋ is presented.展开更多
A novel algorithm was designed and implemented to realize the numerical calculation of the solvent reorganization energy for electron transfer reactions, on the basis of nonequilibrium solvation theory and the dielect...A novel algorithm was designed and implemented to realize the numerical calculation of the solvent reorganization energy for electron transfer reactions, on the basis of nonequilibrium solvation theory and the dielectric polarizable continuum model. Applying the procedure to the well-investigated intramoleeular electron transfer in biphenyl-androstane-naphthyl and biphenyl-androstane-phenanthryl systems, the numerical results of solvent reorganization energy were determined to be around 60 k J/mol, in good agreement with experimental data. Koopman＇s theorem was adopted for the calculation of the electron transfer coupling element, associated with the linear reaction coordinate approximation. The values for this quantity obtained are acceptable when compared with experimental results.展开更多
A two dimensional model approach for the photodetachment dynamics of closed shell an-ionic systems in presence of external light field have been proposed in the context of polar environmental media. The effects of str...A two dimensional model approach for the photodetachment dynamics of closed shell an-ionic systems in presence of external light field have been proposed in the context of polar environmental media. The effects of strong coupling between the solvent polarization and the extra charge in the system were studied by a simple model. The electronic states of con-cerned halide ions are represented by a two dimensional model Hamiltonian with a potential V（x,y）=-V0e^-σ（x^2＋y^2）. The time dependent Fourier grid Hamiltonian method have been used to follow the detachment process with fairly high intensities of light. The environmental effects on the dynamics are sought to be modeled by two different ways. The first one was the presence of polar solvents which perturb the energy levels of anionic systems by changing the effective potential surface and the second one was allowing the fluctuation of the well depth randomly to mimic the system in a more realistic view point. The average detachment rate constant is calculated as a function of important parameters of the used light field to explain the effects of solvent field on the dynamical behavior of dipole bound anionic system at least in a qualitative way.展开更多
Convection-dispersion of fluids flowing through porous media is an important phenomenon in immiscible and miscible displacement in hydrocarbon reservoirs. Exact calculation of this problem leads to perform more robust...Convection-dispersion of fluids flowing through porous media is an important phenomenon in immiscible and miscible displacement in hydrocarbon reservoirs. Exact calculation of this problem leads to perform more robust reservoir simulation and reliable prediction. There are various techniques that have been proposed to solve convection-dispersion equation. To check the validity of these techniques, the convection-dispersion equation was solved numerically using a series of well known numerical techniques. Such techniques that employed in this study include method of line, explicit, implicit, Crank-Nicolson and Barakat-Clark. Several cases were considered as input, and convection-dispersion equation was solved using the aforementioned techniques. Moreover the error analysis was also carried out based on the comparison of numerical and analytical results. Finally it was observed that method of line and explicit methods are not capable of simulating the convection-dispersion equation for wide range of input parameters. The Barakat-Clark method was also failed to predict accurate results and in some cases it had large deviation from analytical solution. On the other hand, the simulation results of implicit and Crank-Nicolson have more qualitative and quantitative agreement with those obtained by the analytical solutions.展开更多
Water is the most abundant compound inherently existing in bio-oils. Thus understanding the role of water within bio-oils upgrading process is essential for future engineering scale-up design. In this study, furfural ...Water is the most abundant compound inherently existing in bio-oils. Thus understanding the role of water within bio-oils upgrading process is essential for future engineering scale-up design. In this study, furfural was chosen as bio-oils model compound, and the catalytic hydrogenation of furfural over commercial 5%, Ru/C catalyst was firstly investigated in a series of gradient variable water/ethanol mixture solvents. Water had a significant effect on the distribution of product yields. The dominant reaction pathways varied with the water contents in the water/ethanol mixture solvents. Typically, when ethanol was used as the solvent, the main products were obtained by the hydrogenation of carbonyl group or furan ring. When pure water was used as the solvent, the rearrangement reaction of furfural to cyclopentanone should be selectively promoted theoretically. However, serious polymerization and resinification were observed herein in catalytic hydrogenation system of pure water. The catalyst surface was modified by the water-insoluble polymers, and consequently, a relative low yield of cyclopentanone was obtained. A plausible multiple competitive reaction mechanism between polymerization reaction and the hydrogenation of furfural was suggested in this study. Characterizations(TG,FT-IR,SEM)were employed to analyze and explain our experiments.展开更多
We describe the synthesis of even-dispersed palladium nanoparticles(Pd NPs)confined within a cellulose nanofiber(CNF)matrix for developing a high-performance and recyclable catalyst.The CNF matrix was composed of CNF-...We describe the synthesis of even-dispersed palladium nanoparticles(Pd NPs)confined within a cellulose nanofiber(CNF)matrix for developing a high-performance and recyclable catalyst.The CNF matrix was composed of CNF-assembled mesoporous nanosheets and appeared as soft and hydrophilic foam.Ultrafine Pd NPs(∼6 nm)with high-loading(9.6 wt%)were in situ grown on these mesoporous nanosheets,and their dense spatial distributions were likely to generate nano-confinement catalytic effects on the reactants.Consequently,the CNF-confined Pd NPs(CNF-Pd)exhibited an enhanced room-temperature catalytic activity on the model reaction of 4-nitrophenol hydrogenation with a highest rate constant of 8.8×10^−3 s^−1 and turnover frequency of 2640 h The CNF Pd catalyst possessed good chemical stability and recyclability in aqueous media which could be reused for at least six cycles without losing activity.Moreover,chemoselective reduction of 3 nitrostyrene was achieved with high yield(80%–98%)of 3-aminostyrene in alcohol/water cosolvent.Overall,this work demonstrates a positive nanoconfinement effect of CNFs for developing stable and recyclable metal NP catalysts.展开更多
基金supported by the National Key Research and Development Program of China(2018YFA0208600)the National Science Foundation of China(21773032,21972023,21533001,22022301,91545107,91745201)。
基金Supported by the National Key Technologies Research and Development Program of China during the 1 lth Five-Year Plan Period （2007BAB22B01） and the Young Science Foundation of Jiangxi Province Education Office （GJJ11124）.
文摘The solvent extraction technology, was applied to recover Cu^2＋ and Ni^2＋ from plating wastewater.Lix984N was chosen as the extractant due to-its gooff extraction performance. The influence parame-ters were examlned. The results show that the separation of Cu^2＋ and Ni＂ from sulphate medium can be realized by adjusting pH value with the help of Lix984N. For extracting Cu^2＋ and Ni^2＋, the optimal pH values are 4 and 10.5, and the maximal extraction percentages are 92.9% and 93.0%, respectively .With recovered Cu^2＋ and Ni^2＋ stripped in 170g.L^ -1 and 200 g.L^-1 H2SO4 medium, the stripping percentages of Cu^2＋ and Ni^2＋ are 92.9% and 93.0%, respectively. This method is simple and can be used to recover Cu^2＋ and Ni^2＋ from plating wastewater. And a flow sheet for separation of Cu^2＋ and Ni^2＋ is presented.
文摘A novel algorithm was designed and implemented to realize the numerical calculation of the solvent reorganization energy for electron transfer reactions, on the basis of nonequilibrium solvation theory and the dielectric polarizable continuum model. Applying the procedure to the well-investigated intramoleeular electron transfer in biphenyl-androstane-naphthyl and biphenyl-androstane-phenanthryl systems, the numerical results of solvent reorganization energy were determined to be around 60 k J/mol, in good agreement with experimental data. Koopman＇s theorem was adopted for the calculation of the electron transfer coupling element, associated with the linear reaction coordinate approximation. The values for this quantity obtained are acceptable when compared with experimental results.
文摘A two dimensional model approach for the photodetachment dynamics of closed shell an-ionic systems in presence of external light field have been proposed in the context of polar environmental media. The effects of strong coupling between the solvent polarization and the extra charge in the system were studied by a simple model. The electronic states of con-cerned halide ions are represented by a two dimensional model Hamiltonian with a potential V（x,y）=-V0e^-σ（x^2＋y^2）. The time dependent Fourier grid Hamiltonian method have been used to follow the detachment process with fairly high intensities of light. The environmental effects on the dynamics are sought to be modeled by two different ways. The first one was the presence of polar solvents which perturb the energy levels of anionic systems by changing the effective potential surface and the second one was allowing the fluctuation of the well depth randomly to mimic the system in a more realistic view point. The average detachment rate constant is calculated as a function of important parameters of the used light field to explain the effects of solvent field on the dynamical behavior of dipole bound anionic system at least in a qualitative way.
文摘Convection-dispersion of fluids flowing through porous media is an important phenomenon in immiscible and miscible displacement in hydrocarbon reservoirs. Exact calculation of this problem leads to perform more robust reservoir simulation and reliable prediction. There are various techniques that have been proposed to solve convection-dispersion equation. To check the validity of these techniques, the convection-dispersion equation was solved numerically using a series of well known numerical techniques. Such techniques that employed in this study include method of line, explicit, implicit, Crank-Nicolson and Barakat-Clark. Several cases were considered as input, and convection-dispersion equation was solved using the aforementioned techniques. Moreover the error analysis was also carried out based on the comparison of numerical and analytical results. Finally it was observed that method of line and explicit methods are not capable of simulating the convection-dispersion equation for wide range of input parameters. The Barakat-Clark method was also failed to predict accurate results and in some cases it had large deviation from analytical solution. On the other hand, the simulation results of implicit and Crank-Nicolson have more qualitative and quantitative agreement with those obtained by the analytical solutions.
基金Supported by the National Basic Research Program of China("973"Program,2014CB260408)Tianjin Natural Science Foundation(No.13JCYBJC19300)
文摘Water is the most abundant compound inherently existing in bio-oils. Thus understanding the role of water within bio-oils upgrading process is essential for future engineering scale-up design. In this study, furfural was chosen as bio-oils model compound, and the catalytic hydrogenation of furfural over commercial 5%, Ru/C catalyst was firstly investigated in a series of gradient variable water/ethanol mixture solvents. Water had a significant effect on the distribution of product yields. The dominant reaction pathways varied with the water contents in the water/ethanol mixture solvents. Typically, when ethanol was used as the solvent, the main products were obtained by the hydrogenation of carbonyl group or furan ring. When pure water was used as the solvent, the rearrangement reaction of furfural to cyclopentanone should be selectively promoted theoretically. However, serious polymerization and resinification were observed herein in catalytic hydrogenation system of pure water. The catalyst surface was modified by the water-insoluble polymers, and consequently, a relative low yield of cyclopentanone was obtained. A plausible multiple competitive reaction mechanism between polymerization reaction and the hydrogenation of furfural was suggested in this study. Characterizations(TG,FT-IR,SEM)were employed to analyze and explain our experiments.
基金the National Natural Science Foundation of China(31925028 and 31670583)the Special Project for Double First-Class-Cultivation of Innovative Talents(000/41113102)。
文摘We describe the synthesis of even-dispersed palladium nanoparticles(Pd NPs)confined within a cellulose nanofiber(CNF)matrix for developing a high-performance and recyclable catalyst.The CNF matrix was composed of CNF-assembled mesoporous nanosheets and appeared as soft and hydrophilic foam.Ultrafine Pd NPs(∼6 nm)with high-loading(9.6 wt%)were in situ grown on these mesoporous nanosheets,and their dense spatial distributions were likely to generate nano-confinement catalytic effects on the reactants.Consequently,the CNF-confined Pd NPs(CNF-Pd)exhibited an enhanced room-temperature catalytic activity on the model reaction of 4-nitrophenol hydrogenation with a highest rate constant of 8.8×10^−3 s^−1 and turnover frequency of 2640 h The CNF Pd catalyst possessed good chemical stability and recyclability in aqueous media which could be reused for at least six cycles without losing activity.Moreover,chemoselective reduction of 3 nitrostyrene was achieved with high yield(80%–98%)of 3-aminostyrene in alcohol/water cosolvent.Overall,this work demonstrates a positive nanoconfinement effect of CNFs for developing stable and recyclable metal NP catalysts.
