Novel modified activated carbons （ACs） with enhanced adsorptive properties were obtained coating by chitosan （CS）, polyethylene glycol （PEG） and blends of the two polymers （0：1, 1：0, 1：1, 1：2 and 2：1 wt/wt...Novel modified activated carbons （ACs） with enhanced adsorptive properties were obtained coating by chitosan （CS）, polyethylene glycol （PEG） and blends of the two polymers （0：1, 1：0, 1：1, 1：2 and 2：1 wt/wt） on ACs by an impregnation technique. The adsorption perfor- mances of the pristine, acidified and polymer-impregnated ACs were studied using methylene blue as a model adsorbate. The adsorbents were characterized using Four- ier transform infrared spectroscopy, scanning electron microscopy and abrasion hardness tests. The average coating thicknesses were between 10 to 23 microns. The pore sizes, pore densities and pore capacities of the activated carbons increased as the wt-% PEG in the coating increased. The highest adsorption capacity （424.7 mg/g） was obtained for the chitosan-coated ACs and this adsorption was well described by the Langmuir isotherm model. The kinetic results were best described by the pseudo-second-order kinetic model. The highest rate constant was obtained with the ACs modified with the CS：PEG （2：1） coating and this result was almost 2.6 times greater than that of the unmodified ACs. The CS/PEG impregnated ACs also displayed superior hardness （-90%）, compared to unmodified ACs （-85%）. Overall the chitosan had a greater effect on improving adsorption capacity whereas the polyethylene glycol enhanced the adsorption rate.展开更多
在聚偏氟乙烯(PVDF)溶液膜表面喷涂壳聚糖(CS)醋酸溶液,用浸没相转变法制备PVDF多孔膜,研究CS溶液对多孔膜的结构和性能的影响并探讨了成膜机理。结果表明,随着溶液膜表面CS溶液体积的增加PVDF膜的孔隙率提高,膜表面的亲水性大幅度提高...在聚偏氟乙烯(PVDF)溶液膜表面喷涂壳聚糖(CS)醋酸溶液,用浸没相转变法制备PVDF多孔膜,研究CS溶液对多孔膜的结构和性能的影响并探讨了成膜机理。结果表明,随着溶液膜表面CS溶液体积的增加PVDF膜的孔隙率提高,膜表面的亲水性大幅度提高,β晶含量降低而α晶的含量提高;喷涂CS溶液前PVDF膜的上表面结构致密,喷涂CS溶液后PVDF膜上表面呈现多孔结构,其断面结构均为指状大孔结构;喷涂CS溶液的体积为2 m L、4 mL和6 m L的PVDF膜,其水通量先增加后降低,分别为683.33 L/m^2·h、1121.57 L/m^2·h、1171.36 L/m^2·h和1029.02 L/m^2·h。用不同方法制备的PVDF膜,其结构和性能不同,因为膜上表面的成膜机理不同。展开更多
文摘Novel modified activated carbons （ACs） with enhanced adsorptive properties were obtained coating by chitosan （CS）, polyethylene glycol （PEG） and blends of the two polymers （0：1, 1：0, 1：1, 1：2 and 2：1 wt/wt） on ACs by an impregnation technique. The adsorption perfor- mances of the pristine, acidified and polymer-impregnated ACs were studied using methylene blue as a model adsorbate. The adsorbents were characterized using Four- ier transform infrared spectroscopy, scanning electron microscopy and abrasion hardness tests. The average coating thicknesses were between 10 to 23 microns. The pore sizes, pore densities and pore capacities of the activated carbons increased as the wt-% PEG in the coating increased. The highest adsorption capacity （424.7 mg/g） was obtained for the chitosan-coated ACs and this adsorption was well described by the Langmuir isotherm model. The kinetic results were best described by the pseudo-second-order kinetic model. The highest rate constant was obtained with the ACs modified with the CS：PEG （2：1） coating and this result was almost 2.6 times greater than that of the unmodified ACs. The CS/PEG impregnated ACs also displayed superior hardness （-90%）, compared to unmodified ACs （-85%）. Overall the chitosan had a greater effect on improving adsorption capacity whereas the polyethylene glycol enhanced the adsorption rate.
文摘在聚偏氟乙烯(PVDF)溶液膜表面喷涂壳聚糖(CS)醋酸溶液,用浸没相转变法制备PVDF多孔膜,研究CS溶液对多孔膜的结构和性能的影响并探讨了成膜机理。结果表明,随着溶液膜表面CS溶液体积的增加PVDF膜的孔隙率提高,膜表面的亲水性大幅度提高,β晶含量降低而α晶的含量提高;喷涂CS溶液前PVDF膜的上表面结构致密,喷涂CS溶液后PVDF膜上表面呈现多孔结构,其断面结构均为指状大孔结构;喷涂CS溶液的体积为2 m L、4 mL和6 m L的PVDF膜,其水通量先增加后降低,分别为683.33 L/m^2·h、1121.57 L/m^2·h、1171.36 L/m^2·h和1029.02 L/m^2·h。用不同方法制备的PVDF膜,其结构和性能不同,因为膜上表面的成膜机理不同。
