The paper deals with the application of multiwall carbon nanotubes(CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the ...The paper deals with the application of multiwall carbon nanotubes(CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the good adsorption ability of CNTs, with respect to classic active carbon, even for different dye types. The effect of surface treatments of CNTs was primarily investigated, revealing that neither the presence of residual catalyst nor common surface treatment(oxidation) affects the CNT's performances. Therefore less expensive nonpurified CNTs were assessed as good and economically convenient alternative for the process. In order to gain in generality in adsorption kinetic modelling, the parameters of the "best fitting" pseudo-second order model have been correlated to the main process variables(the dye initial concentration and the specific mass of CNTs.) setting-up a predictive kinetic model useful design new application of these materials in currently operating industrial operations for adsorption. In addition, isothermal data were used to screen all the relevant adsorption isotherms models and the Temkin model was confirmed as the more effective to accurately fit equilibrium data for any of the considered different dye types.展开更多
Equilibrium sorption amount, desorption diffusion coefficients and sorption diffusion coefficients of CO2 in poly（l-lactic acid） （PLLA） films at elevated pressures were determined by the gravimetric method, in whi...Equilibrium sorption amount, desorption diffusion coefficients and sorption diffusion coefficients of CO2 in poly（l-lactic acid） （PLLA） films at elevated pressures were determined by the gravimetric method, in which the Fick＇s diffusion model was applied to analyze both the desorption and sorption processes. The equilibrium sorption amount of CO2 in PLLA increased with lowering temperature and elevating pressure at the temperature range from 40 to 60 ℃ and pressure from 10^4 to 2x10^4 kPa. Desorption diffusion coefficients were greatly influenced by the equilibrium sorption amount, and they were in the same order of magnitude as the sorption diffusion coefficients. The scan electron microscope （SEM） photos demonstrated that there was no foaming phenomenon of the PLLA film during desorption and sorption processes. The XRD spectra implied that the crystalline degree of PLLA film decreased after CO2 processing. It was concluded that PLLA polymer could be well swollen and plasticized by supercritical CO2.展开更多
The adsorplion behavior of dyes on a variety of sisal based activated carbonfibers (SACF) has been studied in this paper The results show that this kind of ACFhas excellent adsorption capacities for some organic (dye)...The adsorplion behavior of dyes on a variety of sisal based activated carbonfibers (SACF) has been studied in this paper The results show that this kind of ACFhas excellent adsorption capacities for some organic (dye) molecules. SACF canremove nearly all methylene blue, crystal violet, bromophenol blue and Eriochromeblue black R from water after static adsorption for 24 h. at 30℃ The adsorptionamounts can reach more than 400 mg/g when adding 50 mg SACF into 50 ml dyesolution. Under the same conditions, the absorption amounts of xylenol orangefluorescein and Eriochrome black T were lower On the other hand, the adsorptionamounts change along with the characteristics of adsorbents. The SACFs activatedabove 840 ℃ which have higher specific surface areas and wider pore radii, havehigher adsorption amounts for the dyes. The researching results also show that foeadsorption rates of dyes onto SACFs decrease by the order of methylene blue,Eriochrome blue black R and crystal violet.展开更多
文摘The paper deals with the application of multiwall carbon nanotubes(CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the good adsorption ability of CNTs, with respect to classic active carbon, even for different dye types. The effect of surface treatments of CNTs was primarily investigated, revealing that neither the presence of residual catalyst nor common surface treatment(oxidation) affects the CNT's performances. Therefore less expensive nonpurified CNTs were assessed as good and economically convenient alternative for the process. In order to gain in generality in adsorption kinetic modelling, the parameters of the "best fitting" pseudo-second order model have been correlated to the main process variables(the dye initial concentration and the specific mass of CNTs.) setting-up a predictive kinetic model useful design new application of these materials in currently operating industrial operations for adsorption. In addition, isothermal data were used to screen all the relevant adsorption isotherms models and the Temkin model was confirmed as the more effective to accurately fit equilibrium data for any of the considered different dye types.
基金Supported by the National Natura Science Foundation of China （21076185）.
文摘Equilibrium sorption amount, desorption diffusion coefficients and sorption diffusion coefficients of CO2 in poly（l-lactic acid） （PLLA） films at elevated pressures were determined by the gravimetric method, in which the Fick＇s diffusion model was applied to analyze both the desorption and sorption processes. The equilibrium sorption amount of CO2 in PLLA increased with lowering temperature and elevating pressure at the temperature range from 40 to 60 ℃ and pressure from 10^4 to 2x10^4 kPa. Desorption diffusion coefficients were greatly influenced by the equilibrium sorption amount, and they were in the same order of magnitude as the sorption diffusion coefficients. The scan electron microscope （SEM） photos demonstrated that there was no foaming phenomenon of the PLLA film during desorption and sorption processes. The XRD spectra implied that the crystalline degree of PLLA film decreased after CO2 processing. It was concluded that PLLA polymer could be well swollen and plasticized by supercritical CO2.
文摘The adsorplion behavior of dyes on a variety of sisal based activated carbonfibers (SACF) has been studied in this paper The results show that this kind of ACFhas excellent adsorption capacities for some organic (dye) molecules. SACF canremove nearly all methylene blue, crystal violet, bromophenol blue and Eriochromeblue black R from water after static adsorption for 24 h. at 30℃ The adsorptionamounts can reach more than 400 mg/g when adding 50 mg SACF into 50 ml dyesolution. Under the same conditions, the absorption amounts of xylenol orangefluorescein and Eriochrome black T were lower On the other hand, the adsorptionamounts change along with the characteristics of adsorbents. The SACFs activatedabove 840 ℃ which have higher specific surface areas and wider pore radii, havehigher adsorption amounts for the dyes. The researching results also show that foeadsorption rates of dyes onto SACFs decrease by the order of methylene blue,Eriochrome blue black R and crystal violet.
