A series of undoped and lanthanide doped MIL-53(Fe)/Ln-Fe_(3)O_(4)(Ln=La,Nd,or Gd) metal-organic frameworks(MOFs) were prepared by the solvothermal method.All prepared samples were characterized by X-ray diffraction(X...A series of undoped and lanthanide doped MIL-53(Fe)/Ln-Fe_(3)O_(4)(Ln=La,Nd,or Gd) metal-organic frameworks(MOFs) were prepared by the solvothermal method.All prepared samples were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),Brunauer-Emmett-Teller(BET) measurements,scanning electron microscopy(SEM),and thermal analysis.XRD and FT-IR results ascertain the successful MOF formation for all prepared samples.MIL-53(Fe)/La-Fe_(3)O_(4) has the smallest particle size of 8.6 nm,the largest BET surface area of 54.2 m^(2)/g,and the highest porosity.Undoped and different lanthanide doped MIL-53(Fe) we re employed as sorbents for the removal of methylene blue(MB)dye from aqueous solutions to examine the doping benefit and the effect of the dopant size on the sorption performance.Doping causes MOFs to act as pH-independent sorbents,which make it applicable at any condition.Adsorption follows pseudo-second-order kinetic model,and doped sorbents attain equilibrium faster.Langmuir isotherms are followed,except for MIL-53(Fe)/La-Fe_(3)O_(4).The adsorption capacity increases with increasing the dopant ion size,100.5 mg/g for La-doped MOF,which is about four times higher than that of undoped MOF.The adsorption mechanism involves chemical interactions between Lewis acid in magnetite MIL-53(Fe) series and Lewis base in MB.展开更多
Two 2D layer complexes {[La（TBTA）1.5（phen）2H2O].3H2O}n （1） and {[Ce（TBTA）l.5（phen）2H2O]-3H2O}n （2） （H2TBTA = 2,3,5,6-tetrabromoterephthalic acid, phen = 1.10-phenanthroline） have been synthesized and cha...Two 2D layer complexes {[La（TBTA）1.5（phen）2H2O].3H2O}n （1） and {[Ce（TBTA）l.5（phen）2H2O]-3H2O}n （2） （H2TBTA = 2,3,5,6-tetrabromoterephthalic acid, phen = 1.10-phenanthroline） have been synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and thermogravimetric analyses. Both crystals belong to monoclinic, space group P21/n. Crystal data for 1： a = 8.7097（11）, b = 34.276（4）, c = 13.7281（17） A, β = 95.397（2）°, V= 4080.1（9） A3, Z = 4, LaC36H24Br6N4O10, Mr= 1290.96, Dc = 2.102 g/cm3,μ（MoKa） = 6.983 mm-1, F（000） = 2460.0, T = 296（2） K, the final R （I 〉 2σ（I）） = 0.0478 and wR （all data） = 0.0985 for 10127 independent （Rint = 0.0775） and 7137 observed reflections with I 〉 2σ（I）. Crystal data for 2： a = 8.709（2）, b = 34.202（9）, c = 13.685（4） A, β = 95.714（4）, V= 4055.9（19） A3, Z = 4, CeBr6C36H24O10N4, Mr = 1292.17, Dc = 2.116 g/cm3, μ（MoKa） = 7.094 mm-1, F（000） = 2464.0, T= 296（2） K, the final R（I 〉 2σ（I）） = 0.0590 and wR（all data） = 0.1453 for 10014 independent （Rint = 0.1253） and 6081 observed reflections with I 〉 2σ（I）. Both complexes are allomerism with the general molecular formula of {[M（TBTA）1.5（phen）2H2O].3H2O}n. In the structures, the H2TBTA ligands adopt a monodentate coordination mode. Both the 2D layer frameworks are further extended to be 3D layers via H-bonding interactions.展开更多
文摘A series of undoped and lanthanide doped MIL-53(Fe)/Ln-Fe_(3)O_(4)(Ln=La,Nd,or Gd) metal-organic frameworks(MOFs) were prepared by the solvothermal method.All prepared samples were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),Brunauer-Emmett-Teller(BET) measurements,scanning electron microscopy(SEM),and thermal analysis.XRD and FT-IR results ascertain the successful MOF formation for all prepared samples.MIL-53(Fe)/La-Fe_(3)O_(4) has the smallest particle size of 8.6 nm,the largest BET surface area of 54.2 m^(2)/g,and the highest porosity.Undoped and different lanthanide doped MIL-53(Fe) we re employed as sorbents for the removal of methylene blue(MB)dye from aqueous solutions to examine the doping benefit and the effect of the dopant size on the sorption performance.Doping causes MOFs to act as pH-independent sorbents,which make it applicable at any condition.Adsorption follows pseudo-second-order kinetic model,and doped sorbents attain equilibrium faster.Langmuir isotherms are followed,except for MIL-53(Fe)/La-Fe_(3)O_(4).The adsorption capacity increases with increasing the dopant ion size,100.5 mg/g for La-doped MOF,which is about four times higher than that of undoped MOF.The adsorption mechanism involves chemical interactions between Lewis acid in magnetite MIL-53(Fe) series and Lewis base in MB.
基金Supported by the International Scientific and Technological Cooperation Projects of Shanxi Province (2011081022)International S&T Cooperation Program of China (No. 2011DFA51980)the Natural Science Foundation of Shanxi Province (No. 2009021024)
文摘Two 2D layer complexes {[La（TBTA）1.5（phen）2H2O].3H2O}n （1） and {[Ce（TBTA）l.5（phen）2H2O]-3H2O}n （2） （H2TBTA = 2,3,5,6-tetrabromoterephthalic acid, phen = 1.10-phenanthroline） have been synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and thermogravimetric analyses. Both crystals belong to monoclinic, space group P21/n. Crystal data for 1： a = 8.7097（11）, b = 34.276（4）, c = 13.7281（17） A, β = 95.397（2）°, V= 4080.1（9） A3, Z = 4, LaC36H24Br6N4O10, Mr= 1290.96, Dc = 2.102 g/cm3,μ（MoKa） = 6.983 mm-1, F（000） = 2460.0, T = 296（2） K, the final R （I 〉 2σ（I）） = 0.0478 and wR （all data） = 0.0985 for 10127 independent （Rint = 0.0775） and 7137 observed reflections with I 〉 2σ（I）. Crystal data for 2： a = 8.709（2）, b = 34.202（9）, c = 13.685（4） A, β = 95.714（4）, V= 4055.9（19） A3, Z = 4, CeBr6C36H24O10N4, Mr = 1292.17, Dc = 2.116 g/cm3, μ（MoKa） = 7.094 mm-1, F（000） = 2464.0, T= 296（2） K, the final R（I 〉 2σ（I）） = 0.0590 and wR（all data） = 0.1453 for 10014 independent （Rint = 0.1253） and 6081 observed reflections with I 〉 2σ（I）. Both complexes are allomerism with the general molecular formula of {[M（TBTA）1.5（phen）2H2O].3H2O}n. In the structures, the H2TBTA ligands adopt a monodentate coordination mode. Both the 2D layer frameworks are further extended to be 3D layers via H-bonding interactions.
