The effect of two alkylpyridinium ionic liquids (py-iLs) including N-butylpyridinium hydrogen sulfate (BpyHSO4) and N-hexylpyridinium hydrogen sulfate (HpyHSO4) on the kinetics of copper electrodeposition from a...The effect of two alkylpyridinium ionic liquids (py-iLs) including N-butylpyridinium hydrogen sulfate (BpyHSO4) and N-hexylpyridinium hydrogen sulfate (HpyHSO4) on the kinetics of copper electrodeposition from acidic sulfate solution was investigated by cyclic voltammetry and potentiodynamic polarization measurements. Results from cyclic voltammetry indicate that these py-iLs have a pronounced inhibiting effect on CuE+ electroreduction and there exists a typical nucleation and growth process. Kinetic parameters such as Tafel slope, transfer coefficient and exchange current density obtained from Tafel plots, lead to the conclusion that py-iLs inhibit the charge transfer by slightly changing the copper electrodeposition mechanism through their adsorption on the cathodic surface. In addition, scanning electron microscope (SEM) and X-ray diffraction analyses reveal that the presence of these additives leads to more leveled and fine-grained cathodic deposits without changing the crystal structure of the electrodeposited copper but strongly affects the crystallographic orientation by significantly inhibiting the growth of (111), (200) and (311) planes.展开更多
SO 4 2- and Zn 2+ or Cd 2+ were added to three variable charge soils in different sequences. In one sequence sulfate was added first, and in the other, Zn 2+ or Cd 2+ ...SO 4 2- and Zn 2+ or Cd 2+ were added to three variable charge soils in different sequences. In one sequence sulfate was added first, and in the other, Zn 2+ or Cd 2+ first. The addition of sulfate to the system invariably caused an increase in adsorption of the heavy metal added, with the effect more remarkable when the soil reacted with the sulfate prior to the metal. The shift in pH 50 for both Zn and Cd adsorption was also comparatively larger in the first sequence of reactions. It was suggested that the increase in negative charge density and the resultant negative potential of the soil were the primary cause of the pronounced effect of sulfate on adsorption of Zn or Cd, and the formation of the ternary surface complex S SO 4 M might also play a role in the effect.展开更多
The gold sorption from thiosulphate solutions on carbon sorbents and on anion exchangers was studied. It was shown that the anion exchangers AV-17-10P and AP-100 are the most effective and selective at pH=5-8. These a...The gold sorption from thiosulphate solutions on carbon sorbents and on anion exchangers was studied. It was shown that the anion exchangers AV-17-10P and AP-100 are the most effective and selective at pH=5-8. These anion exchangers can be recommended for the gold recovery from the industrial solutions.展开更多
In the interest of accelerating aniline degradation, Fe2+ and chelated Fe2+ activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric aci...In the interest of accelerating aniline degradation, Fe2+ and chelated Fe2+ activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate(EDTA) to maintain available Fe2+. The results indicate that the concentration of chelating agent and ferrous ion didn't follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe2+ results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe2+/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.展开更多
An acid sulfate soil sample was successively extracted with deionized water, 1 mol L-1 KCl and 0.000 5 mol L-l Ca(OH)2 solutions. The results showed that only very small amounts of acidity were extracted by deionized ...An acid sulfate soil sample was successively extracted with deionized water, 1 mol L-1 KCl and 0.000 5 mol L-l Ca(OH)2 solutions. The results showed that only very small amounts of acidity were extracted by deionized water, possibly through slow jarosite hydrolysis. Acid release through jarosite hydrolysis was greatly enhanced by Ca(OH)2 extraction at the expense of the added OH- being neutralized by the acid released. Successive extraction of the sample with KCl removed the largest amounts of acidity from the sample. However, it is likely that the major form of acidity released by KCl extraction was exchangeable acidity. The results also show the occurrence of low or non charged Al and Fe species in water and Ca(OH)2 extracts after first a few extractions. It appears that such a phenomenon was related to a decreasing EC value with increasing number of extractions.展开更多
Technological advances in the past 30 years have boosted the use of PSM (membrane separation processes), important for its efficiency and flexibility of operation. These processes can be used in many types of separa...Technological advances in the past 30 years have boosted the use of PSM (membrane separation processes), important for its efficiency and flexibility of operation. These processes can be used in many types of separation, with some advantages over the usual separation processes. NF (nanofiltration) is a membrane separation technique, which has properties intermediate between reverse osmosis and ultrafiltration in terms of separated species, because the average of the pores is in the range of 1/2 to 10 nm, and the separation occurs in function of load and size of the species. Usually removes species in solution with an effective diameter of about 1 nm or larger and multivalent ions to a greater extent than monovalent ions. The objective was to study the formation of biofouling on the surface of commercial nanofiltration membrane (Osmonics/GE) and surface membrane synthesized in our laboratory. The study was conducted in permeation system with filtration cell with tangential displacement of 15 bar for 8 days flow. DBNPA (2,2-dibromo-3-nitrilopropionamide) was used as a biocide agent, and an anti-fouling, in concentrations of 5 and 300 ppm, respectively, added to the water coming from the Beach Sea Galleon, RJ. The results demonstrated that there was no change in the flow and rejection of sulphate ions, even in the presence of anti-fouling. The count of aerobic, anaerobic and BRS (sulfate reducing bacteria) in seawater before and after using the DBNPA showed efficiency in controlling these groups of microorganisms and biofouling microbial consortium consisting of the existing in seawater.展开更多
Limestone Calcined Clay Cement(LC^(3)) is a newly proposed low-carbon cement,which can effectively reduce energy consumption and carbon emissions of the traditional cement industry without changing the basic mechanica...Limestone Calcined Clay Cement(LC^(3)) is a newly proposed low-carbon cement,which can effectively reduce energy consumption and carbon emissions of the traditional cement industry without changing the basic mechanical properties of cement-based materials.In this study,the degradation process of mortar samples of limestone and calcined clay cementitious material under sulfate attack is studied by both macroscopic and microscopic analysis.The results show that compared with pure Portland cement,the addition of calcined clay and limestone can significantly reduce the expansion rate,loss of dynamic modulus and mass loss of mortar specimens under sulfate attack.The addition of calcined clay and limestone will refine the pore size distribution of mortar specimens,then inhibiting the diffusion of sulfate and formation of corrosive products,therefore leading to a significant improvement of the sulfate resistance.展开更多
基金Projects(51204080, 51274108) supported by the National Natural Science Foundation of ChinaProject(2011FA009) supported by the Natural Science Foundation of Yunnan Province, ChinaProject(2011FZ020) supported by the Application Research Foundation of Yunnan Province, China
文摘The effect of two alkylpyridinium ionic liquids (py-iLs) including N-butylpyridinium hydrogen sulfate (BpyHSO4) and N-hexylpyridinium hydrogen sulfate (HpyHSO4) on the kinetics of copper electrodeposition from acidic sulfate solution was investigated by cyclic voltammetry and potentiodynamic polarization measurements. Results from cyclic voltammetry indicate that these py-iLs have a pronounced inhibiting effect on CuE+ electroreduction and there exists a typical nucleation and growth process. Kinetic parameters such as Tafel slope, transfer coefficient and exchange current density obtained from Tafel plots, lead to the conclusion that py-iLs inhibit the charge transfer by slightly changing the copper electrodeposition mechanism through their adsorption on the cathodic surface. In addition, scanning electron microscope (SEM) and X-ray diffraction analyses reveal that the presence of these additives leads to more leveled and fine-grained cathodic deposits without changing the crystal structure of the electrodeposited copper but strongly affects the crystallographic orientation by significantly inhibiting the growth of (111), (200) and (311) planes.
文摘SO 4 2- and Zn 2+ or Cd 2+ were added to three variable charge soils in different sequences. In one sequence sulfate was added first, and in the other, Zn 2+ or Cd 2+ first. The addition of sulfate to the system invariably caused an increase in adsorption of the heavy metal added, with the effect more remarkable when the soil reacted with the sulfate prior to the metal. The shift in pH 50 for both Zn and Cd adsorption was also comparatively larger in the first sequence of reactions. It was suggested that the increase in negative charge density and the resultant negative potential of the soil were the primary cause of the pronounced effect of sulfate on adsorption of Zn or Cd, and the formation of the ternary surface complex S SO 4 M might also play a role in the effect.
文摘The gold sorption from thiosulphate solutions on carbon sorbents and on anion exchangers was studied. It was shown that the anion exchangers AV-17-10P and AP-100 are the most effective and selective at pH=5-8. These anion exchangers can be recommended for the gold recovery from the industrial solutions.
基金Project(2010B050200007)supported by the Foundation of Science and Technology Planning Project of Guangdong Province,ChinaProject(2011ZM0054)supported by the Fundamental Research Funds for the Central Universities,China+1 种基金Project(2011K0013)supported by the Research Fund Program of Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology,ChinaProject(2012)supported by the Research Funds of Guangdong Provincial Key Laboratory of Atmospheric environment and Pollution Control,China
文摘In the interest of accelerating aniline degradation, Fe2+ and chelated Fe2+ activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate(EDTA) to maintain available Fe2+. The results indicate that the concentration of chelating agent and ferrous ion didn't follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe2+ results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe2+/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.
文摘An acid sulfate soil sample was successively extracted with deionized water, 1 mol L-1 KCl and 0.000 5 mol L-l Ca(OH)2 solutions. The results showed that only very small amounts of acidity were extracted by deionized water, possibly through slow jarosite hydrolysis. Acid release through jarosite hydrolysis was greatly enhanced by Ca(OH)2 extraction at the expense of the added OH- being neutralized by the acid released. Successive extraction of the sample with KCl removed the largest amounts of acidity from the sample. However, it is likely that the major form of acidity released by KCl extraction was exchangeable acidity. The results also show the occurrence of low or non charged Al and Fe species in water and Ca(OH)2 extracts after first a few extractions. It appears that such a phenomenon was related to a decreasing EC value with increasing number of extractions.
文摘Technological advances in the past 30 years have boosted the use of PSM (membrane separation processes), important for its efficiency and flexibility of operation. These processes can be used in many types of separation, with some advantages over the usual separation processes. NF (nanofiltration) is a membrane separation technique, which has properties intermediate between reverse osmosis and ultrafiltration in terms of separated species, because the average of the pores is in the range of 1/2 to 10 nm, and the separation occurs in function of load and size of the species. Usually removes species in solution with an effective diameter of about 1 nm or larger and multivalent ions to a greater extent than monovalent ions. The objective was to study the formation of biofouling on the surface of commercial nanofiltration membrane (Osmonics/GE) and surface membrane synthesized in our laboratory. The study was conducted in permeation system with filtration cell with tangential displacement of 15 bar for 8 days flow. DBNPA (2,2-dibromo-3-nitrilopropionamide) was used as a biocide agent, and an anti-fouling, in concentrations of 5 and 300 ppm, respectively, added to the water coming from the Beach Sea Galleon, RJ. The results demonstrated that there was no change in the flow and rejection of sulphate ions, even in the presence of anti-fouling. The count of aerobic, anaerobic and BRS (sulfate reducing bacteria) in seawater before and after using the DBNPA showed efficiency in controlling these groups of microorganisms and biofouling microbial consortium consisting of the existing in seawater.
基金supported in part by grants from National Natural Science Foundation of China(52278259).
文摘Limestone Calcined Clay Cement(LC^(3)) is a newly proposed low-carbon cement,which can effectively reduce energy consumption and carbon emissions of the traditional cement industry without changing the basic mechanical properties of cement-based materials.In this study,the degradation process of mortar samples of limestone and calcined clay cementitious material under sulfate attack is studied by both macroscopic and microscopic analysis.The results show that compared with pure Portland cement,the addition of calcined clay and limestone can significantly reduce the expansion rate,loss of dynamic modulus and mass loss of mortar specimens under sulfate attack.The addition of calcined clay and limestone will refine the pore size distribution of mortar specimens,then inhibiting the diffusion of sulfate and formation of corrosive products,therefore leading to a significant improvement of the sulfate resistance.