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
One of today＇s major challenges is to provide green materials for a cleaner environment. We have conducted studies on carbon dioxide（CO2） adsorption and conversion to valuable products by an ecofriendly approach ba...One of today＇s major challenges is to provide green materials for a cleaner environment. We have conducted studies on carbon dioxide（CO2） adsorption and conversion to valuable products by an ecofriendly approach based in chitosan/graphene oxide（CSGO） nanocomposite film. Rheological behavior indicates that the CSGO has a better solvation property than the pure chitosan. An adsorption capacity of 1.0152 mmol CO2/g of CSGO nanocomposite at4.6 bar was observed. The catalytic behavior of the CSGO nanocomposite in the presence of tetra-n-butylammonium iodide（n-Bu4 NI） as co-catalyst was evaluated for the cycloaddition of CO2 to epoxides, to give cyclic carbonates, in the absence of any solvent. These results strongly suggest that the CSGO nanocomposite may open new vistas towards the development of ecofriendly material for catalytic conversion and adsorption of CO2 on industrial scale.展开更多
A novel quaternized-chitosan-modified reduced graphene oxide（HACC-RGO） combined the adsorption advantages of RGO and 2-Hydroxypropyltrimethyl ammonium chloride chitosan（HACC）. The adsorption property of HACC-RGO s...A novel quaternized-chitosan-modified reduced graphene oxide（HACC-RGO） combined the adsorption advantages of RGO and 2-Hydroxypropyltrimethyl ammonium chloride chitosan（HACC）. The adsorption property of HACC-RGO sheets for methyl orange（MO） was demonstrated and compared with RGO and HACC. The removal ratios of HACC-RGO sheets reached 92.6% for MO after a 24 h adsorption. The adsorption kinetics, isotherms and thermodynamics were investigated to indicate that the kinetics and equilibrium adsorptions were well-described by pseudo-second-order kinetic and Freundlich isotherm model, respectively. The thermodynamic parameters suggested that the adsorption process was spontaneous and endothermic in nature. Moreover, monodisperse HACC-RGO/CS beads were fabricated by the microfluidic method. The adsorption and desorption of HACC-RGO/CS beads for MO were studied. After three adsorptiondesorption cycles, the adsorption capacity remained above 55% and the desorption capacity was not below 70%. The HACC-RGO/CS beads can be reused and have great potential applications in removing organic dyes from polluted water.展开更多
Along with the growing severity of environment problem and energy crisis, it is inevitable to develop novel materials, which are contributed to the removal of hazardous pollutants from contaminated water. Herein, we r...Along with the growing severity of environment problem and energy crisis, it is inevitable to develop novel materials, which are contributed to the removal of hazardous pollutants from contaminated water. Herein, we reported a fhcile method for the preparation of free-standing chitosan/graphene oxide(CS/GO) composite sponges with low density, where CS/GO mixtures were first synthesized by tlie homogeneous reaction of chitosan and graphene oxide in aqueous acetic acid solution;then CS/GO sponges were obtained by lyophilizing the suspension, which were prefrozen at -20 ℃ and in liquid nitrogen successively. The obtained layered sponge showed good water- driven shape memory effect and was a good adsorbent of Co^2+ and Ni^2+ witli a large adsorption capacity of 224.8 and 423.7 mg/g, respectively. Importantly, the successive adsorption-desorption studies employing CS/GO sponge indicated that the composite could be regenerated by HC1 solution and reused in more than five cycles with regeneration efficiency beyond 80%. Also, the resultant sponge was explored as an exceptionally adsorbent for the removal of organic dye(e.g., methylene blue, MB).展开更多
Porous graphene oxide/chitosan （PGOC） materials were prepared by a unidirectional freeze-drying method. Their porous structure, mechanical property and adsorption for metal ions were investigated. The results show t...Porous graphene oxide/chitosan （PGOC） materials were prepared by a unidirectional freeze-drying method. Their porous structure, mechanical property and adsorption for metal ions were investigated. The results show that the incorporation of graphene oxide （GO） significantly increased the compressive strength of the PGOC materials. The saturated adsorption capacity of Pb^2＋ increased about 31%, up to 99 mg/g when 5 wt% GO was incorporated These biodegradable, nontoxic, efficient PGOC materials will be a potential adsorbent for metal ions in aqueous solution.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 KU Brain Pool 2017 of Konkuk University,Seoul,South KoreaFundacao para a Ciência e a Tecnologia(FCT),Portugal(SFRH/BPD/86507/2012)Centro de Quimica de Coimbra(CQC),University of Coimbra for their support
文摘One of today＇s major challenges is to provide green materials for a cleaner environment. We have conducted studies on carbon dioxide（CO2） adsorption and conversion to valuable products by an ecofriendly approach based in chitosan/graphene oxide（CSGO） nanocomposite film. Rheological behavior indicates that the CSGO has a better solvation property than the pure chitosan. An adsorption capacity of 1.0152 mmol CO2/g of CSGO nanocomposite at4.6 bar was observed. The catalytic behavior of the CSGO nanocomposite in the presence of tetra-n-butylammonium iodide（n-Bu4 NI） as co-catalyst was evaluated for the cycloaddition of CO2 to epoxides, to give cyclic carbonates, in the absence of any solvent. These results strongly suggest that the CSGO nanocomposite may open new vistas towards the development of ecofriendly material for catalytic conversion and adsorption of CO2 on industrial scale.
基金the National Natural Science Foundation of China(Nos.50803048 and 50703030)
文摘A novel quaternized-chitosan-modified reduced graphene oxide（HACC-RGO） combined the adsorption advantages of RGO and 2-Hydroxypropyltrimethyl ammonium chloride chitosan（HACC）. The adsorption property of HACC-RGO sheets for methyl orange（MO） was demonstrated and compared with RGO and HACC. The removal ratios of HACC-RGO sheets reached 92.6% for MO after a 24 h adsorption. The adsorption kinetics, isotherms and thermodynamics were investigated to indicate that the kinetics and equilibrium adsorptions were well-described by pseudo-second-order kinetic and Freundlich isotherm model, respectively. The thermodynamic parameters suggested that the adsorption process was spontaneous and endothermic in nature. Moreover, monodisperse HACC-RGO/CS beads were fabricated by the microfluidic method. The adsorption and desorption of HACC-RGO/CS beads for MO were studied. After three adsorptiondesorption cycles, the adsorption capacity remained above 55% and the desorption capacity was not below 70%. The HACC-RGO/CS beads can be reused and have great potential applications in removing organic dyes from polluted water.
基金the National Natural Science Foundation of China(Nos.3120187& U1204804)the Postdoctoral Foundation of China(No.2015M572109)the Postdoctoral Fund of Henan Province,China(No.2014049).
文摘Along with the growing severity of environment problem and energy crisis, it is inevitable to develop novel materials, which are contributed to the removal of hazardous pollutants from contaminated water. Herein, we reported a fhcile method for the preparation of free-standing chitosan/graphene oxide(CS/GO) composite sponges with low density, where CS/GO mixtures were first synthesized by tlie homogeneous reaction of chitosan and graphene oxide in aqueous acetic acid solution;then CS/GO sponges were obtained by lyophilizing the suspension, which were prefrozen at -20 ℃ and in liquid nitrogen successively. The obtained layered sponge showed good water- driven shape memory effect and was a good adsorbent of Co^2+ and Ni^2+ witli a large adsorption capacity of 224.8 and 423.7 mg/g, respectively. Importantly, the successive adsorption-desorption studies employing CS/GO sponge indicated that the composite could be regenerated by HC1 solution and reused in more than five cycles with regeneration efficiency beyond 80%. Also, the resultant sponge was explored as an exceptionally adsorbent for the removal of organic dye(e.g., methylene blue, MB).
基金supported by the National Science Foundation of China(No.50873075)Tianjin Municipal Science and Technology Commission,PR China(No.09JCZDJC23300)
文摘Porous graphene oxide/chitosan （PGOC） materials were prepared by a unidirectional freeze-drying method. Their porous structure, mechanical property and adsorption for metal ions were investigated. The results show that the incorporation of graphene oxide （GO） significantly increased the compressive strength of the PGOC materials. The saturated adsorption capacity of Pb^2＋ increased about 31%, up to 99 mg/g when 5 wt% GO was incorporated These biodegradable, nontoxic, efficient PGOC materials will be a potential adsorbent for metal ions in aqueous solution.
基金This work was supported by the National Natural Science Foundation of China(No.22076044)the Ministry of Education Key Laboratory of Resources and Environmental Systems Optimization(NCEPU).
