Four modified starches with selected charge characteristics including cationic starch(CAS),carboxymethyl starch(CMS),amphoteric starch(AMS) and soluble starch(SS) were investigated as depressants for diaspore in rever...Four modified starches with selected charge characteristics including cationic starch(CAS),carboxymethyl starch(CMS),amphoteric starch(AMS) and soluble starch(SS) were investigated as depressants for diaspore in reverse flotation test using cationic collector(dodecylamine).Adsorption examination,Zeta potential measurement and Fourier transform infrared(FTIR) spectroscopy were used to clarify the role of the surface charge characteristics of starches in determining the adsorption behavior and depression performance as well as the mineral-starch interaction.Results show that the positively charged starches(CAS and AMS) display higher adsorption amounts and also better depression performance compared with the non-ionic(SS) and anionic starch(CMS),benefiting from the favorable electrostatic attraction with diaspore and also electrostatic repulsion with collector.FTIR spectroscopy proves the presence of hydrogen bonds and chemical complexation between mineral and starches in an integrated manner.展开更多
Bibliographic reports on the electric conductivity of pure homoionic montmorillonite at low water content were analyzed in order to stress a general behavior of conductivity. At low water content, the conductivity is ...Bibliographic reports on the electric conductivity of pure homoionic montmorillonite at low water content were analyzed in order to stress a general behavior of conductivity. At low water content, the conductivity is attributed to a mechanism of charge transport involving protons due to the influence of the electric field of the exchangeable cations on water molecules at the solvation shell. Conductivity was analyzed in relation with the polarizing power （ionic potential） of the exchangeable cations and with the influence of the connectivity within samples. The general conclusion stressed is that the connectivity due to the association between 2：1 unit layers （clay fabric） is the main factor on the experimental or ＂macroscopic＂ electric conductivity of pure homoionic montmorillonite at low water content. Considerations on the experimental conditions of different bibliographic reports were also made. The conclusion and the considerations made on experimental conditions are a good starting point for future researches on electric conductivity ofhomoionic montmorillonite at low water content.展开更多
A room temperature ionic liquid crystal, 1-dodecyl-3-ethylimidazolium iodide （C12EImI）, and an ionic liquid, 1-decyl-3- ethylimidazolium iodide （Cl0EImI）, have been synthesized, characterized and employed as the e...A room temperature ionic liquid crystal, 1-dodecyl-3-ethylimidazolium iodide （C12EImI）, and an ionic liquid, 1-decyl-3- ethylimidazolium iodide （Cl0EImI）, have been synthesized, characterized and employed as the electrolyte for dye-sensitized solar cells （DSSC）. The physicochemical properties show that a smectic A （SmA） phase with a lamellar structure is formed in CIzEImI. Both C^2EImI and Cl0EImI have good electrochemical and thermal stability facilitating their use in DSSC. The steady-state voltammograms reveal that the diffusion coefficient of I3- in C^2EImI is larger than that in CmEImI, which is at- tributed to the existence of the SmA phase in Ca2EImI. Because the iodide species are located between the layers of imidazo- lium cations in CjzEImI, exchange reaction-based diffusion is increased with a consequent increase in, the overall diffusion. The electrochemical impedance spectrum reveals that charge recombination at the dyed TiOJelectrolyte interface of a C12EImI-based DSSC is reduced due to the increase in I3- diffusion, resulting in higher open-circuit voltage. Moreover, both short-circuit current density and fill factor of the Cl2EImI based DSSC increase, as a result of the increasing transport of I3 in C^2EImI. Consequently, the photoelectric conversion efficiency of C^2EImI-based DSSC is higher than that of the Cl0EImI-based DSSC.展开更多
基金Projects(50804055,50974134) supported by the National Natural Science Foundation of ChinaProject(09JJ3100) supported by Hunan Provincial Natural Science Foundation,China
文摘Four modified starches with selected charge characteristics including cationic starch(CAS),carboxymethyl starch(CMS),amphoteric starch(AMS) and soluble starch(SS) were investigated as depressants for diaspore in reverse flotation test using cationic collector(dodecylamine).Adsorption examination,Zeta potential measurement and Fourier transform infrared(FTIR) spectroscopy were used to clarify the role of the surface charge characteristics of starches in determining the adsorption behavior and depression performance as well as the mineral-starch interaction.Results show that the positively charged starches(CAS and AMS) display higher adsorption amounts and also better depression performance compared with the non-ionic(SS) and anionic starch(CMS),benefiting from the favorable electrostatic attraction with diaspore and also electrostatic repulsion with collector.FTIR spectroscopy proves the presence of hydrogen bonds and chemical complexation between mineral and starches in an integrated manner.
文摘Bibliographic reports on the electric conductivity of pure homoionic montmorillonite at low water content were analyzed in order to stress a general behavior of conductivity. At low water content, the conductivity is attributed to a mechanism of charge transport involving protons due to the influence of the electric field of the exchangeable cations on water molecules at the solvation shell. Conductivity was analyzed in relation with the polarizing power （ionic potential） of the exchangeable cations and with the influence of the connectivity within samples. The general conclusion stressed is that the connectivity due to the association between 2：1 unit layers （clay fabric） is the main factor on the experimental or ＂macroscopic＂ electric conductivity of pure homoionic montmorillonite at low water content. Considerations on the experimental conditions of different bibliographic reports were also made. The conclusion and the considerations made on experimental conditions are a good starting point for future researches on electric conductivity ofhomoionic montmorillonite at low water content.
基金supported by the National Basic Research Program of China(2011CBA00700)the National High Technology Research and Development Program of China(2011AA050510)the National Natural Science Foundation of China(21273242,21003130,21173227)
文摘A room temperature ionic liquid crystal, 1-dodecyl-3-ethylimidazolium iodide （C12EImI）, and an ionic liquid, 1-decyl-3- ethylimidazolium iodide （Cl0EImI）, have been synthesized, characterized and employed as the electrolyte for dye-sensitized solar cells （DSSC）. The physicochemical properties show that a smectic A （SmA） phase with a lamellar structure is formed in CIzEImI. Both C^2EImI and Cl0EImI have good electrochemical and thermal stability facilitating their use in DSSC. The steady-state voltammograms reveal that the diffusion coefficient of I3- in C^2EImI is larger than that in CmEImI, which is at- tributed to the existence of the SmA phase in Ca2EImI. Because the iodide species are located between the layers of imidazo- lium cations in CjzEImI, exchange reaction-based diffusion is increased with a consequent increase in, the overall diffusion. The electrochemical impedance spectrum reveals that charge recombination at the dyed TiOJelectrolyte interface of a C12EImI-based DSSC is reduced due to the increase in I3- diffusion, resulting in higher open-circuit voltage. Moreover, both short-circuit current density and fill factor of the Cl2EImI based DSSC increase, as a result of the increasing transport of I3 in C^2EImI. Consequently, the photoelectric conversion efficiency of C^2EImI-based DSSC is higher than that of the Cl0EImI-based DSSC.
