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
Ionic liquid (IL) trihexyl (tetradecyl) phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104) was impregnated on XAD-7 resin. The solvent impreganated resin (SIR) was prepared and applied in Cr(VI) removal....Ionic liquid (IL) trihexyl (tetradecyl) phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104) was impregnated on XAD-7 resin. The solvent impreganated resin (SIR) was prepared and applied in Cr(VI) removal. The morphology and the thermal stability of the resins were explored. The effects of equilibrium time and initial pH value on Cr(VI) adsorption were investigated. Adsorption isotherm, separation and desorption of the SIR, and selectivity of SIR were also explored. The results show that Cyphos IL 104 exists in the inner XAD-7 resin, and the optimum pH value range of the SIR for Cr(VI) extraction is 0 to 2. When NaOH used as desorption solution, the Cr(VI) can be effectively desorbed from the SIR.展开更多
Polyethyleneimine(PEI)modified palygorskite(Pal)was used for the adsorption of Cr(VI)in aqueous solution.The absorbent was characterized by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetric analysis(...Polyethyleneimine(PEI)modified palygorskite(Pal)was used for the adsorption of Cr(VI)in aqueous solution.The absorbent was characterized by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetric analysis(TGA).Characterized results confirmed that the Pal has been successfully modified by PEI.The modification of PEI increased the Cr(VI)adsorption performance of the Pal by the adsorption combined reduction mechanism,and amino groups of the adsorbent play the main role in the enhanced Cr(VI)adsorption.The maximum adsorption capacity was 51.10 mg·g^-1 at pH4.0 and 25°C.The adsorption kinetics of Cr(VI)on the adsorbent conforms to the Langmuir isotherm model.The maximum adsorption occurs at pH3,and then the adsorption capacity of PEI-Pal was decreased with the increase of p H values.The adsorption kinetics of Cr(VI)on PEI-Pal was modeled with pseudo-second-order model.The addition of Cl^-,SO4^2-and PO4^3-reduced the Cr(VI)adsorption by competition with Cr(VI)for the active sites of PEI-Pal.The Cr(VI)saturated PEI-Pal can be regenerated in alkaline solution,and the adsorption capacity can still be maintained at 30.44 mg·g^-1 after 4 cycles.The results demonstrate that PEI-Pal can be used as a potential adsorbent of Cr(VI)in aqueous solutions.展开更多
A hydroxyl-functionalized magnetic fungus nanocomposite(MFH@GO)was prepared by a simple one-pot method for the removal of Cr(VI)from wastewater.The adsorption behavior of MFH@GO to Cr(VI)in wastewater was discussed in...A hydroxyl-functionalized magnetic fungus nanocomposite(MFH@GO)was prepared by a simple one-pot method for the removal of Cr(VI)from wastewater.The adsorption behavior of MFH@GO to Cr(VI)in wastewater was discussed in detail.At pH of 5.0 and temperature of 323.15 K,MFH@GO had higher adsorption capacity to Cr(VI)(58.4 mg/g)than the unmodified fungus and GO.Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),thermogravimetry and differential thermal analysis(TG-DTA),scanning electron microscopy and energy dispersive X-Ray spectroscopy(SEM-EDX)were employed to determine the characteristics of MFH@GO.Results showed that magnetic graphene oxide nanoparticles significantly enhanced the physiochemical properties of the fungi.In addition,the adsorption mechanisms analyses show that Cr(VI)could be reduced and mineralized into ferric chromate in residues.These results suggested that MFH@GO could be used as an promising and alternative biosorbent for removal of Cr(VI)from industrial wastewater.展开更多
Coal fly ashes WSRA and BQRA were ball milled for 5 h to produce their ultrafine coal fly ashes WSUA and BQUA, respectively. Batch kinetic, isotherm and pH effect on adsorption were studied to evaluate removal of Cr ...Coal fly ashes WSRA and BQRA were ball milled for 5 h to produce their ultrafine coal fly ashes WSUA and BQUA, respectively. Batch kinetic, isotherm and pH effect on adsorption were studied to evaluate removal of Cr （VI） from aqueous solutions by ultrafine coal fly ashes comparing with raw coal fly ashes. The kinetics of adsorption indicates the process to be intraparticle diffusion controlled and follows the Lagergren first-order kinetics for all coal fly ashes. The first-order rate constants （k1） of Cr （VI） adsorption onto WSRA, WSUA, BQRA and BQUA are 1.981, 1.497, 2.119 and 1.500 （×10^-2） min^-1, respectively. The adsorption capacities of WSUA and BQUA are much better than those of WSRA and BQRA. Equilibrium adsorption data of all coal fly ashes well satisfy the Langmuir isotherm. The adsorbed amounts of Cr （VI） onto WSUA and BQUA decrease from pH 2 to pH 6 and then increase up to pH 12.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Project (51174184) sponsored by the National Natural Science Foundation of ChinaProject (2012CBA01202) supported by the National Basic Research Program of ChinaProject (KGZD-EW-201-1) supported by the Key Research Program of the Chinese Academy of Sciences
文摘Ionic liquid (IL) trihexyl (tetradecyl) phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104) was impregnated on XAD-7 resin. The solvent impreganated resin (SIR) was prepared and applied in Cr(VI) removal. The morphology and the thermal stability of the resins were explored. The effects of equilibrium time and initial pH value on Cr(VI) adsorption were investigated. Adsorption isotherm, separation and desorption of the SIR, and selectivity of SIR were also explored. The results show that Cyphos IL 104 exists in the inner XAD-7 resin, and the optimum pH value range of the SIR for Cr(VI) extraction is 0 to 2. When NaOH used as desorption solution, the Cr(VI) can be effectively desorbed from the SIR.
基金funded by the National Natural Science Foundation of China(21677092)the Scientific Research Program funded by Shaanxi Provincial Education Department(15JK1095)。
文摘Polyethyleneimine(PEI)modified palygorskite(Pal)was used for the adsorption of Cr(VI)in aqueous solution.The absorbent was characterized by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetric analysis(TGA).Characterized results confirmed that the Pal has been successfully modified by PEI.The modification of PEI increased the Cr(VI)adsorption performance of the Pal by the adsorption combined reduction mechanism,and amino groups of the adsorbent play the main role in the enhanced Cr(VI)adsorption.The maximum adsorption capacity was 51.10 mg·g^-1 at pH4.0 and 25°C.The adsorption kinetics of Cr(VI)on the adsorbent conforms to the Langmuir isotherm model.The maximum adsorption occurs at pH3,and then the adsorption capacity of PEI-Pal was decreased with the increase of p H values.The adsorption kinetics of Cr(VI)on PEI-Pal was modeled with pseudo-second-order model.The addition of Cl^-,SO4^2-and PO4^3-reduced the Cr(VI)adsorption by competition with Cr(VI)for the active sites of PEI-Pal.The Cr(VI)saturated PEI-Pal can be regenerated in alkaline solution,and the adsorption capacity can still be maintained at 30.44 mg·g^-1 after 4 cycles.The results demonstrate that PEI-Pal can be used as a potential adsorbent of Cr(VI)in aqueous solutions.
基金Project(18B195)supported by Excellent Youth Project of Hunan Education Department,ChinaProjects(51804353,51704093)supported by the National Natural Science Foundation of China+2 种基金Project(kq1801074)supported by Key Projects of Changsha Science and Technology Plan,ChinaProject(2018JJ4010)supported by Hunan Provincial Natural Science Foundation of China(Joint Funds of Provincial and Zhuzhou Municipal)Project(2018JJ3885)supported by Natural Science Foundation of Hunan Province of China(Science Foundation for Youths)。
文摘A hydroxyl-functionalized magnetic fungus nanocomposite(MFH@GO)was prepared by a simple one-pot method for the removal of Cr(VI)from wastewater.The adsorption behavior of MFH@GO to Cr(VI)in wastewater was discussed in detail.At pH of 5.0 and temperature of 323.15 K,MFH@GO had higher adsorption capacity to Cr(VI)(58.4 mg/g)than the unmodified fungus and GO.Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),thermogravimetry and differential thermal analysis(TG-DTA),scanning electron microscopy and energy dispersive X-Ray spectroscopy(SEM-EDX)were employed to determine the characteristics of MFH@GO.Results showed that magnetic graphene oxide nanoparticles significantly enhanced the physiochemical properties of the fungi.In addition,the adsorption mechanisms analyses show that Cr(VI)could be reduced and mineralized into ferric chromate in residues.These results suggested that MFH@GO could be used as an promising and alternative biosorbent for removal of Cr(VI)from industrial wastewater.
基金Funded by the China Post Doctoral Science Foundation (20070411124)the Scientific and Technological Key Project of Shaanxi Province (2006k07-G19)+1 种基金the Industrialization Project of Shaanxi Provincal Department of Education(06JC11)the Scientific and Technological Key Project of Xi’anCity(GG06074)
文摘Coal fly ashes WSRA and BQRA were ball milled for 5 h to produce their ultrafine coal fly ashes WSUA and BQUA, respectively. Batch kinetic, isotherm and pH effect on adsorption were studied to evaluate removal of Cr （VI） from aqueous solutions by ultrafine coal fly ashes comparing with raw coal fly ashes. The kinetics of adsorption indicates the process to be intraparticle diffusion controlled and follows the Lagergren first-order kinetics for all coal fly ashes. The first-order rate constants （k1） of Cr （VI） adsorption onto WSRA, WSUA, BQRA and BQUA are 1.981, 1.497, 2.119 and 1.500 （×10^-2） min^-1, respectively. The adsorption capacities of WSUA and BQUA are much better than those of WSRA and BQRA. Equilibrium adsorption data of all coal fly ashes well satisfy the Langmuir isotherm. The adsorbed amounts of Cr （VI） onto WSUA and BQUA decrease from pH 2 to pH 6 and then increase up to pH 12.
