Cross-linked chitosan(CS),cross-linked chitosan/graphene(CS/RGO10) and cross-linked chitosan/graphene oxide(CS/GO10) were prepared as adsorbents for Cu(Ⅱ).The effects of pH,contact time,adsorbent dosage and initial c...Cross-linked chitosan(CS),cross-linked chitosan/graphene(CS/RGO10) and cross-linked chitosan/graphene oxide(CS/GO10) were prepared as adsorbents for Cu(Ⅱ).The effects of pH,contact time,adsorbent dosage and initial concentration of Cu(Ⅱ) on the adsorbing abilities of CS,CS/RGO10 and CS/GO10 to Cu(Ⅱ) were investigated.The results demonstrate that the adsorption capacities of CS/GO10 and CS/RGO10 are greater than that of CS,especially at pH 5.0 and the adsorption capacities are 202.5,150 and 137.5 mg/g,respectively.Their behaviors obey the Freundlich isotherm model very well.Additionally,CS/GO10 has the shortest time to achieve adsorption equilibrium among them and can be used as a perspective adsorbent for Cu(Ⅱ).展开更多
A novel biosorbent was developed by coating chitosan, a naturally and abundantly available biopolymer, on to activated alumina based on oil shale ash via crosslinking. The adsorbent was characterized by various techni...A novel biosorbent was developed by coating chitosan, a naturally and abundantly available biopolymer, on to activated alumina based on oil shale ash via crosslinking. The adsorbent was characterized by various techniques, such as Fourier transform infrared spectroscopy, scarming＇ elec.tron micros cop.y, the rmogravimetric-differentialthermal analysis, and X-ray photoelectron spectroscope. Batch isothermal equilibrium adsorption experiments were condcted to evaluate the adsorbent for the removal of Cu（Ⅱ） from wastewater. The effect of pH and agitation time on the adsorption capacity was also investigated, indicating that the optimum pH was 6.0. The equilibrium adsorp-tion data were correlated with Langmuir and Freundlich models. The maximum monolayer adsorption capacity of chitosan coated alumina sorbent as obtained from Langmuir adsorption isotherm was fotmd to be 315.46 mg.g-1 for Cu（Ⅱ）. The adsorbent loaded with Cu（Ⅱ） was readily regenerated using 0.1 mol.L-1 sodium hydroxide solution. All these indicated that chitosan coated alumina adsorbent not only have high adsorption activity, but also had good stability in the wastewater treatment process.展开更多
Chitosan and chitosan membranes with Pb(Ⅱ) ion as template were studied. The adsorption isotherms were correlated by dc/dt=-kcn at the temperature of 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃. By means of linear correlation,...Chitosan and chitosan membranes with Pb(Ⅱ) ion as template were studied. The adsorption isotherms were correlated by dc/dt=-kcn at the temperature of 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃. By means of linear correlation, the shapes of the isotherm curves were similar to the kinetic function of 2/C=-kt and the apparent activation energy for with chitosan(123.8 kJ·moL-1) was larger than that of membrane with Pb(Ⅱ) ion(92.3 kJ·moL-1). The chitosan membrane with Pb(Ⅱ) ion template was better "memory" function. The adsorption mechanism of chitosan with Pb(Ⅱ) was studied by IR and XPS. The results indicated that the nitrogen in-NH2 and the oxygen in C3-OH of chitosan were coordination atoms.展开更多
Complexes of chitosan with Mn(Ⅱ) were prepared by adding Mn(OAc)2·4H2O to Chitosan solution. IR, elemental analysis and TG analysis were used to character the complex. The results showed that there were coordina...Complexes of chitosan with Mn(Ⅱ) were prepared by adding Mn(OAc)2·4H2O to Chitosan solution. IR, elemental analysis and TG analysis were used to character the complex. The results showed that there were coordinate bands formed. H2O2 was used to degrade chitosan-Mn(Ⅱ) complex, and the molecular distribution of degraded products were investigated after eliminating Mn(Ⅱ) ions using the cation exchange resin column. The result suggested that the Chitosan could be degraded rapidly, the degradation started from higher molecular weight range, the molecular weight distribution of oligosaccharides was much more narrower than that of degradated products from common methods such as hydrolysis, acidic and oxidizing methods. The index of molecular weight distribution was changed with the average degradability. When exceeding 10 oligosaccharides, the smaller of the DP, the smaller of the index.展开更多
基金Projects(51071067,21271069,J1210040,51238002) supported by the National Natural Science Foundation of ChinaProjects(2013GK3015,2012SK3170) supported by the Science and Technology Program of Hunan Province,China
文摘Cross-linked chitosan(CS),cross-linked chitosan/graphene(CS/RGO10) and cross-linked chitosan/graphene oxide(CS/GO10) were prepared as adsorbents for Cu(Ⅱ).The effects of pH,contact time,adsorbent dosage and initial concentration of Cu(Ⅱ) on the adsorbing abilities of CS,CS/RGO10 and CS/GO10 to Cu(Ⅱ) were investigated.The results demonstrate that the adsorption capacities of CS/GO10 and CS/RGO10 are greater than that of CS,especially at pH 5.0 and the adsorption capacities are 202.5,150 and 137.5 mg/g,respectively.Their behaviors obey the Freundlich isotherm model very well.Additionally,CS/GO10 has the shortest time to achieve adsorption equilibrium among them and can be used as a perspective adsorbent for Cu(Ⅱ).
基金Supported by the National Innovative Projects with Cooperation in terms of Production,Study and Research (OSR-05)the National Science and Technology Major Projects (2008ZX05018-005)
文摘A novel biosorbent was developed by coating chitosan, a naturally and abundantly available biopolymer, on to activated alumina based on oil shale ash via crosslinking. The adsorbent was characterized by various techniques, such as Fourier transform infrared spectroscopy, scarming＇ elec.tron micros cop.y, the rmogravimetric-differentialthermal analysis, and X-ray photoelectron spectroscope. Batch isothermal equilibrium adsorption experiments were condcted to evaluate the adsorbent for the removal of Cu（Ⅱ） from wastewater. The effect of pH and agitation time on the adsorption capacity was also investigated, indicating that the optimum pH was 6.0. The equilibrium adsorp-tion data were correlated with Langmuir and Freundlich models. The maximum monolayer adsorption capacity of chitosan coated alumina sorbent as obtained from Langmuir adsorption isotherm was fotmd to be 315.46 mg.g-1 for Cu（Ⅱ）. The adsorbent loaded with Cu（Ⅱ） was readily regenerated using 0.1 mol.L-1 sodium hydroxide solution. All these indicated that chitosan coated alumina adsorbent not only have high adsorption activity, but also had good stability in the wastewater treatment process.
文摘Chitosan and chitosan membranes with Pb(Ⅱ) ion as template were studied. The adsorption isotherms were correlated by dc/dt=-kcn at the temperature of 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃. By means of linear correlation, the shapes of the isotherm curves were similar to the kinetic function of 2/C=-kt and the apparent activation energy for with chitosan(123.8 kJ·moL-1) was larger than that of membrane with Pb(Ⅱ) ion(92.3 kJ·moL-1). The chitosan membrane with Pb(Ⅱ) ion template was better "memory" function. The adsorption mechanism of chitosan with Pb(Ⅱ) was studied by IR and XPS. The results indicated that the nitrogen in-NH2 and the oxygen in C3-OH of chitosan were coordination atoms.
文摘Complexes of chitosan with Mn(Ⅱ) were prepared by adding Mn(OAc)2·4H2O to Chitosan solution. IR, elemental analysis and TG analysis were used to character the complex. The results showed that there were coordinate bands formed. H2O2 was used to degrade chitosan-Mn(Ⅱ) complex, and the molecular distribution of degraded products were investigated after eliminating Mn(Ⅱ) ions using the cation exchange resin column. The result suggested that the Chitosan could be degraded rapidly, the degradation started from higher molecular weight range, the molecular weight distribution of oligosaccharides was much more narrower than that of degradated products from common methods such as hydrolysis, acidic and oxidizing methods. The index of molecular weight distribution was changed with the average degradability. When exceeding 10 oligosaccharides, the smaller of the DP, the smaller of the index.
