Fenugreek seeds extract was examined as a green corrosion inhibitor for Zn in 2.0 mol/L H2SO4 and 2.0 mol/L HClsolutions by mass loss and electrochemical measurements. Scanning electron microscope （SEM） images show ...Fenugreek seeds extract was examined as a green corrosion inhibitor for Zn in 2.0 mol/L H2SO4 and 2.0 mol/L HClsolutions by mass loss and electrochemical measurements. Scanning electron microscope （SEM） images show that the surfacedamage is decreased in the presence of the inhibitor. X-rays photoelectron spectroscopy （XPS） analysis was performed to identify thecorrosion product, ZnO, and to prove the inhibitor adsorption mechanism. The maximum inhibition efficiency values are 90.7% after1 h and 66.6% after 0.5 h by 200 mL/L of fenugreek extract in H2SO4 and HCl solutions, respectively. Addition of I^- ion greatlyimproves the inhibition efficiency of fenugreek seeds extract for Zn corrosion in HCl due to the synergistic effect. Potentiodynamicpolarization and EIS measurements prove the inhibition ability of fenugreek for Zn corrosion in HCl as indicated by the decreasedcorrosion current density and increased charge transfer resistance values in the presence of fenugreek.展开更多
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
文摘Fenugreek seeds extract was examined as a green corrosion inhibitor for Zn in 2.0 mol/L H2SO4 and 2.0 mol/L HClsolutions by mass loss and electrochemical measurements. Scanning electron microscope （SEM） images show that the surfacedamage is decreased in the presence of the inhibitor. X-rays photoelectron spectroscopy （XPS） analysis was performed to identify thecorrosion product, ZnO, and to prove the inhibitor adsorption mechanism. The maximum inhibition efficiency values are 90.7% after1 h and 66.6% after 0.5 h by 200 mL/L of fenugreek extract in H2SO4 and HCl solutions, respectively. Addition of I^- ion greatlyimproves the inhibition efficiency of fenugreek seeds extract for Zn corrosion in HCl due to the synergistic effect. Potentiodynamicpolarization and EIS measurements prove the inhibition ability of fenugreek for Zn corrosion in HCl as indicated by the decreasedcorrosion current density and increased charge transfer resistance values in the presence of fenugreek.
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.
