Nano-NiO powder was prepared by thermal decomposition of the precursor of NiC2O4·2H2O obtained via Ni(NO3)2·6H2O and H2C2O4·2H2O reacting in ethanol solvent. IR and TGA-DTA indicate physisorption and ch...Nano-NiO powder was prepared by thermal decomposition of the precursor of NiC2O4·2H2O obtained via Ni(NO3)2·6H2O and H2C2O4·2H2O reacting in ethanol solvent. IR and TGA-DTA indicate physisorption and chem- isorption ethanol co-exist in the precursor. XRD suggests the obtained cubic NiO is stable below 700 ℃. TEM shows the as-calcined NiO at 400 ℃ for 2 hours was of narrow distribution, weak agglomeration and small particle size (average 8 nm). The reason for weak agglomeration was explained.展开更多
ZnO,NiO and ZnO@NiO nanocrystals were successfully synthesized and characterized by FTIR,XRD and SEM methods.The average particles sizes of ZnO,NiO and ZnO@NiO were32,50and48nm,respectively.The nanocrystals were exami...ZnO,NiO and ZnO@NiO nanocrystals were successfully synthesized and characterized by FTIR,XRD and SEM methods.The average particles sizes of ZnO,NiO and ZnO@NiO were32,50and48nm,respectively.The nanocrystals were examined assensors for cyanide removal.The cyanide sensing test revealed that,compared with the pure ZnO,NiO,the ZnO@NiO nanocrystalsexhibited highly improved sensing performances.The ZnO@NiO nano crystals were found to have better capacity for iron cyanidethan sodium cyanide.The effects of significant parameters such as contact time,pH(2-12),nanocrystal dose(0.02-0.4g)andcyanide concentration(5-50mg/L)on the removal of cyanide by nanocrystals were explored.At an optimum pH<5,over90%removal of20mg/L cyanide was obtained for nanocrystal dose of0.2g after30min contact time for iron cyanide by ZnO@NiOnano crystals.Cyanide removal was followed by pseudo second order kinetic model for ZnO@NiO nano crystals(k2=4.66×10-2andR2=0.999).The values of standard entralpy change of7.87kJ/mol and standard free energy change of-18.62kJ/mol at298K suggestthe adsorption of cyanide on nanocrystals is an endothermic and spontaneous process.ZnO@NiO nanocrystal is an efficient sensorfor removal of cyanide from water and wastewater.展开更多
文摘Nano-NiO powder was prepared by thermal decomposition of the precursor of NiC2O4·2H2O obtained via Ni(NO3)2·6H2O and H2C2O4·2H2O reacting in ethanol solvent. IR and TGA-DTA indicate physisorption and chem- isorption ethanol co-exist in the precursor. XRD suggests the obtained cubic NiO is stable below 700 ℃. TEM shows the as-calcined NiO at 400 ℃ for 2 hours was of narrow distribution, weak agglomeration and small particle size (average 8 nm). The reason for weak agglomeration was explained.
基金financial support from the Research Council of Islamic Azad University of Yazd
文摘ZnO,NiO and ZnO@NiO nanocrystals were successfully synthesized and characterized by FTIR,XRD and SEM methods.The average particles sizes of ZnO,NiO and ZnO@NiO were32,50and48nm,respectively.The nanocrystals were examined assensors for cyanide removal.The cyanide sensing test revealed that,compared with the pure ZnO,NiO,the ZnO@NiO nanocrystalsexhibited highly improved sensing performances.The ZnO@NiO nano crystals were found to have better capacity for iron cyanidethan sodium cyanide.The effects of significant parameters such as contact time,pH(2-12),nanocrystal dose(0.02-0.4g)andcyanide concentration(5-50mg/L)on the removal of cyanide by nanocrystals were explored.At an optimum pH<5,over90%removal of20mg/L cyanide was obtained for nanocrystal dose of0.2g after30min contact time for iron cyanide by ZnO@NiOnano crystals.Cyanide removal was followed by pseudo second order kinetic model for ZnO@NiO nano crystals(k2=4.66×10-2andR2=0.999).The values of standard entralpy change of7.87kJ/mol and standard free energy change of-18.62kJ/mol at298K suggestthe adsorption of cyanide on nanocrystals is an endothermic and spontaneous process.ZnO@NiO nanocrystal is an efficient sensorfor removal of cyanide from water and wastewater.
