A hierarchical reduced graphene oxide-MnO_(2)@polypyrrole coaxial nanotube composite hydrogel was prepared via oxidative polymerization of pyrrole in the presence of MnO_(2)nanotubes,followed by the hydrothermal treat...A hierarchical reduced graphene oxide-MnO_(2)@polypyrrole coaxial nanotube composite hydrogel was prepared via oxidative polymerization of pyrrole in the presence of MnO_(2)nanotubes,followed by the hydrothermal treatment of graphene oxide and MnO_(2)@polypyrrole coaxial nanotubes.The stable composite hydrogel with a hierarchical network was composed of one-dimensional MnO_(2)@polypyrrole coaxial nanotube and two-dimensional graphene nanosheet and characterized by scanning electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,Brunauer-Emmett-Teller surface,and X-ray photoelectron spectroscopy measurements.The composite hydrogel can be used as an efficient adsorbent for Cr(Ⅵ)removal due to the synergistic interaction between graphene and MnO_(2)@polypyrrole and the hierarchical structure of the hydrogel.Moreover,the composite hydrogel is easily separated because of its stable monolith,and it is reusable(76.8%of removal ability remaining after five adsorption-desorption cycles).The simple fabrication and cost-effective separation process together with the excellent absorption performance endow the composite hydrogel with great potential for practical wastewater treatment.展开更多
Sugarcane pulp residue （SPR）, a waste from sugar-refinery, which possesses a large surface area, can be used for removing chromium （Cr（Ⅲ） and Cr（Ⅵ）） from wastewater. In this work, the kinetics, isotherms of...Sugarcane pulp residue （SPR）, a waste from sugar-refinery, which possesses a large surface area, can be used for removing chromium （Cr（Ⅲ） and Cr（Ⅵ）） from wastewater. In this work, the kinetics, isotherms of Cr（Ⅲ） and Cr（V[） adsorption and their removal by SPR were investigated. The results show that the removal percentages of Cr（Ⅵ） and Cr（Ⅲ） increase with increasing SPR dosage and temperature and decrease with increasing SPR particle size and the initial concentration of chromium ions. However, the influence of pH value on the Cr（Ⅵ） removal differs from that of the Cr（Ⅲ） removal. The Cr（Ⅵ） removal percentage decreases with increasing pH values, while the Cr（Ⅲ） removal percentage increases with increasing pH value. The adsorption kinetics of Cr（Ⅵ） and Cr（Ⅲ） well fits with pseudo-second-order model. Langmuir adsorption isotherm can well describe the adsorption phenomena of chromium ions with the maximum adsorption capacity of 0.567 mg/g for Cr（Ⅵ） and 3.446 mg/g for Cr（Ⅲ）. Moreover, SPR reveals higher adsorption capacity for Cr（Ⅲ） than that for Cr（Ⅵ）, which implies that SPR has more potential application for Cr（Ⅲ）-containing wastewater treatment than that for Cr（Ⅵ）-containing wastewater treatment.展开更多
Magnetic chitosan composites(Fe3O4@chitosan) were synthesized in one single-step, characterized and applied in Cr(VI) removal from water. With the increase of loading proportion of chitosan, Cr(Ⅵ) adsorption capacity...Magnetic chitosan composites(Fe3O4@chitosan) were synthesized in one single-step, characterized and applied in Cr(VI) removal from water. With the increase of loading proportion of chitosan, Cr(Ⅵ) adsorption capacity of Fe3O4@chitosan composites increased from 10.771 to 21.040 mg/g. The optimum adsorption capacities of Cr(VI) on Fe3O4@chitosan-3 were found in a pH range of 3.0-5.0. Kinetic study results show that the adsorption process follows pseudo-second-order model, indicating that the rate-limiting step in the adsorption of Cr(Ⅵ) involves chemisorptions. Moreover, FT-IR spectra analysis confirms that the amine and hydroxyl groups of chitosan are predominantly responsible for binding. Results from this work demonstrate that the prepared Fe3O4@chitosan composites possess great potential in Cr(Ⅵ) removal from contaminated water.展开更多
In this work, the transport and removal of Cr(Ⅵ) were achieved through supported liquid membrane(SLM) by using a 5,17, di-tert-butyl-11,23-bis[(1,4-dioxa-8-azaspiro [4,5]decanyl)methyl]-25,26,27,28-tetrahydroxy calix...In this work, the transport and removal of Cr(Ⅵ) were achieved through supported liquid membrane(SLM) by using a 5,17, di-tert-butyl-11,23-bis[(1,4-dioxa-8-azaspiro [4,5]decanyl)methyl]-25,26,27,28-tetrahydroxy calix[4]arene carrier, dissolved in 2-nitrophenyl octyl ether dichloromethane.The studied parameters are the solvent effect in the membrane phase, the effect of carrier concentration, and the acid type in the donor phase.The Celgard 2500 was used as a membrane support.We used the Danesi mass transfer model to calculate the permeability coefficients for each studied parameter.In addition, AFM and SEM techniques were used to characterize the surface morphology of the prepared Celgard 2500 membrane that included the calix[4]arene carrier.展开更多
FeOOH supported on organo-bentonite was prepared by organo-bentonite with good absorptive property,and the effects of dosage of the composite adsorbent,temperature,and Cr(Ⅵ)concentration on the removal rate of Cr(Ⅵ)...FeOOH supported on organo-bentonite was prepared by organo-bentonite with good absorptive property,and the effects of dosage of the composite adsorbent,temperature,and Cr(Ⅵ)concentration on the removal rate of Cr(Ⅵ)in the simulated wastewater were studied.The results indicated that the removal effect of Cr(Ⅵ)was good when the mass fraction of organo-bentonite was 3‰.The removal rate of Cr(Ⅵ)from the simulated wastewater could reach the maximum 98.37% under the following conditions:the dosage of the composite adsorbent was 1.0g;the temperature was 25℃;Cr(Ⅵ)concentration was 10mg/L;the oscillating time was 4h.展开更多
Aerogel composed of polyaniline/cellulose nanofiber(PANI/CNF)was synthesized by a two-step method and used as an adsorbent to remove Cr(Ⅵ)from wastewater in this study.Adsorption results showed that PANI/CNF aerogel ...Aerogel composed of polyaniline/cellulose nanofiber(PANI/CNF)was synthesized by a two-step method and used as an adsorbent to remove Cr(Ⅵ)from wastewater in this study.Adsorption results showed that PANI/CNF aerogel adsorbent exhibited a high adsorption capacity of 298.5 mg·g-1 for Cr(Ⅵ)(318 K,pH=2.0).Meanwhile,the adsorption process can be fitted well with the pseudo-second-order model and the Freundlich model.Moreover,the Cr(Ⅵ)removal efficiency of the adsorbent remained above 85%after ten recycling experiments,indicating that PANI/CNF aerogel had excellent stability and reusability.Therefore,PANI/CNF aerogel showed a potential application in the treatment of chromium-containing wastewater.展开更多
基金Funded by the Open/Innovation Fund of Hubei Three Gorges Laboratory(No.SK212002)。
文摘A hierarchical reduced graphene oxide-MnO_(2)@polypyrrole coaxial nanotube composite hydrogel was prepared via oxidative polymerization of pyrrole in the presence of MnO_(2)nanotubes,followed by the hydrothermal treatment of graphene oxide and MnO_(2)@polypyrrole coaxial nanotubes.The stable composite hydrogel with a hierarchical network was composed of one-dimensional MnO_(2)@polypyrrole coaxial nanotube and two-dimensional graphene nanosheet and characterized by scanning electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,Brunauer-Emmett-Teller surface,and X-ray photoelectron spectroscopy measurements.The composite hydrogel can be used as an efficient adsorbent for Cr(Ⅵ)removal due to the synergistic interaction between graphene and MnO_(2)@polypyrrole and the hierarchical structure of the hydrogel.Moreover,the composite hydrogel is easily separated because of its stable monolith,and it is reusable(76.8%of removal ability remaining after five adsorption-desorption cycles).The simple fabrication and cost-effective separation process together with the excellent absorption performance endow the composite hydrogel with great potential for practical wastewater treatment.
基金Projects(2006AA06Z374, 2007AA021304) supported by the National High-Tech Research and Development Program of ChinaProject(2008SK2007) supported by the Key Program of Science and Technology of Hunan Province, China
文摘Sugarcane pulp residue （SPR）, a waste from sugar-refinery, which possesses a large surface area, can be used for removing chromium （Cr（Ⅲ） and Cr（Ⅵ）） from wastewater. In this work, the kinetics, isotherms of Cr（Ⅲ） and Cr（V[） adsorption and their removal by SPR were investigated. The results show that the removal percentages of Cr（Ⅵ） and Cr（Ⅲ） increase with increasing SPR dosage and temperature and decrease with increasing SPR particle size and the initial concentration of chromium ions. However, the influence of pH value on the Cr（Ⅵ） removal differs from that of the Cr（Ⅲ） removal. The Cr（Ⅵ） removal percentage decreases with increasing pH values, while the Cr（Ⅲ） removal percentage increases with increasing pH value. The adsorption kinetics of Cr（Ⅵ） and Cr（Ⅲ） well fits with pseudo-second-order model. Langmuir adsorption isotherm can well describe the adsorption phenomena of chromium ions with the maximum adsorption capacity of 0.567 mg/g for Cr（Ⅵ） and 3.446 mg/g for Cr（Ⅲ）. Moreover, SPR reveals higher adsorption capacity for Cr（Ⅲ） than that for Cr（Ⅵ）, which implies that SPR has more potential application for Cr（Ⅲ）-containing wastewater treatment than that for Cr（Ⅵ）-containing wastewater treatment.
基金Projects(51304252,51374237)supported by the National Natural Science Foundation of China
文摘Magnetic chitosan composites(Fe3O4@chitosan) were synthesized in one single-step, characterized and applied in Cr(VI) removal from water. With the increase of loading proportion of chitosan, Cr(Ⅵ) adsorption capacity of Fe3O4@chitosan composites increased from 10.771 to 21.040 mg/g. The optimum adsorption capacities of Cr(VI) on Fe3O4@chitosan-3 were found in a pH range of 3.0-5.0. Kinetic study results show that the adsorption process follows pseudo-second-order model, indicating that the rate-limiting step in the adsorption of Cr(Ⅵ) involves chemisorptions. Moreover, FT-IR spectra analysis confirms that the amine and hydroxyl groups of chitosan are predominantly responsible for binding. Results from this work demonstrate that the prepared Fe3O4@chitosan composites possess great potential in Cr(Ⅵ) removal from contaminated water.
基金supported financially by the Scientific Research Projects (BAP) of Pamukkale University, Denizli-Turkey (2013 FBE 045)
文摘In this work, the transport and removal of Cr(Ⅵ) were achieved through supported liquid membrane(SLM) by using a 5,17, di-tert-butyl-11,23-bis[(1,4-dioxa-8-azaspiro [4,5]decanyl)methyl]-25,26,27,28-tetrahydroxy calix[4]arene carrier, dissolved in 2-nitrophenyl octyl ether dichloromethane.The studied parameters are the solvent effect in the membrane phase, the effect of carrier concentration, and the acid type in the donor phase.The Celgard 2500 was used as a membrane support.We used the Danesi mass transfer model to calculate the permeability coefficients for each studied parameter.In addition, AFM and SEM techniques were used to characterize the surface morphology of the prepared Celgard 2500 membrane that included the calix[4]arene carrier.
文摘FeOOH supported on organo-bentonite was prepared by organo-bentonite with good absorptive property,and the effects of dosage of the composite adsorbent,temperature,and Cr(Ⅵ)concentration on the removal rate of Cr(Ⅵ)in the simulated wastewater were studied.The results indicated that the removal effect of Cr(Ⅵ)was good when the mass fraction of organo-bentonite was 3‰.The removal rate of Cr(Ⅵ)from the simulated wastewater could reach the maximum 98.37% under the following conditions:the dosage of the composite adsorbent was 1.0g;the temperature was 25℃;Cr(Ⅵ)concentration was 10mg/L;the oscillating time was 4h.
基金National Natural Science Foundation of China(Nos.52073046,51873036,and 51673039)Fundamental Research Funds for the Central Universities,China(Nos.2232020D-08 and 2232019A3-01)+3 种基金Natural Science Foundation of Shanghai,China(No.19ZR1470900)Shanghai Shuguang Program,China(No.19SG28)International Joint Laboratory for Advanced Fiber and Low-Dimension Materials,China(No.18520750400)Initial Research Funds for Young Teachers of Donghua University,China(No.106-07-0053089)。
文摘Aerogel composed of polyaniline/cellulose nanofiber(PANI/CNF)was synthesized by a two-step method and used as an adsorbent to remove Cr(Ⅵ)from wastewater in this study.Adsorption results showed that PANI/CNF aerogel adsorbent exhibited a high adsorption capacity of 298.5 mg·g-1 for Cr(Ⅵ)(318 K,pH=2.0).Meanwhile,the adsorption process can be fitted well with the pseudo-second-order model and the Freundlich model.Moreover,the Cr(Ⅵ)removal efficiency of the adsorbent remained above 85%after ten recycling experiments,indicating that PANI/CNF aerogel had excellent stability and reusability.Therefore,PANI/CNF aerogel showed a potential application in the treatment of chromium-containing wastewater.
