A niobate/titanat nanoflakes(Nb/TiNFs)composite was synthesized via the hydrothermal method and used to remove Pb(Ⅱ)from water.XRD,TEM,and SEM results indicate that Nb/TiNFs appear as nanoflakes,of which the primary ...A niobate/titanat nanoflakes(Nb/TiNFs)composite was synthesized via the hydrothermal method and used to remove Pb(Ⅱ)from water.XRD,TEM,and SEM results indicate that Nb/TiNFs appear as nanoflakes,of which the primary crystal phase is tri-titanate.Nb/TiNFs show rapid adsorption kinetics and the result fits well with the pseudo-second order model.The key mechanism of adsorption is ion-exchange between metal and-ONa/H.According to the Langmuir isotherm model,the maximum capacity of Pb(Ⅱ)is 488.323 mg·g^-1.The relatively low RL values indicate that Nb/TiNFs exhibit favorable adsorption of Pb(Ⅱ).Nb/TiNFs indicate high adsorption capacity over a broad pH range.Co-existing inorganic ions(Na+and Ca^2+)have a slight inhibition effect on adsorption,and HA moderately inhibits the adsorption of Pb(Ⅱ)on Nb/TiNFs.Because of the simple method of synthesis and high removal efficiency for heavy metals,Nb/TiNFs are a promising material in remediation of heavy metal polluted water.展开更多
Perrhenate(ReO4-) was used as nonradioactive surrogate for the radionuclide pertechnetate(99TcO-4) to investigate the potential of using starch-stabilized zero valent iron(ZVI) nanoparticles for reductive immobilizati...Perrhenate(ReO4-) was used as nonradioactive surrogate for the radionuclide pertechnetate(99TcO-4) to investigate the potential of using starch-stabilized zero valent iron(ZVI) nanoparticles for reductive immobilization of pertechnetate in soil and groundwater.Batch kinetic tests indicated that the starch-stabilized ZVI nanoparticles were able to reductively remove ～96% of perrhenate(10 mg/L) from water within 8 h.XRD analyses confirmed that ReO 2 was the reduction product.A pseudo-first-order kinetic model was able to interpret the kinetic data,which gave a pseudo first order rate constant(kobs) value of 0.43h-1 at pH 6.9 and room temperature(25℃).Increasing solution pH up to 8 progressively increased the reaction rate.However,highly alkaline pH(10) resulted in much inhibited reaction rate.Consequently,the optimal pH range was identified to be from 7 to 8.Increasing solution temperature from 15 to 45℃ increased k obs from 0.38 to 0.53 h-1.The classical Arrhenius equation was able to interpret the temperature effect,which gave a low activation energy value of 7.61 kJ/mol.When the ReO-4-loaded loess was treated with the stabilized nanoparticles suspension([Fe]=560 mg/L),the water leachable ReO-4 was reduced by 57% and nearly all eluted Re was in the form of ReO2.This finding indicates that starch-stabilized ZVI nanoparticles are promising for facilitating in situ immobilization of ReO-4 in soil and groundwater.展开更多
基金Funded by the National Natural Science Foundation of China(41272375)the Key Research and Development Plan of Shanxi Province(No.201903D121085)。
文摘A niobate/titanat nanoflakes(Nb/TiNFs)composite was synthesized via the hydrothermal method and used to remove Pb(Ⅱ)from water.XRD,TEM,and SEM results indicate that Nb/TiNFs appear as nanoflakes,of which the primary crystal phase is tri-titanate.Nb/TiNFs show rapid adsorption kinetics and the result fits well with the pseudo-second order model.The key mechanism of adsorption is ion-exchange between metal and-ONa/H.According to the Langmuir isotherm model,the maximum capacity of Pb(Ⅱ)is 488.323 mg·g^-1.The relatively low RL values indicate that Nb/TiNFs exhibit favorable adsorption of Pb(Ⅱ).Nb/TiNFs indicate high adsorption capacity over a broad pH range.Co-existing inorganic ions(Na+and Ca^2+)have a slight inhibition effect on adsorption,and HA moderately inhibits the adsorption of Pb(Ⅱ)on Nb/TiNFs.Because of the simple method of synthesis and high removal efficiency for heavy metals,Nb/TiNFs are a promising material in remediation of heavy metal polluted water.
基金supported by the National Natural Science Foundation of China (41072265 and 40810152)the Science-Technology Research of Colleges in Shanxi Province (20091022)+1 种基金the Shanxi Provincial 100 Talents Program,Chinaan Auburn University VPR’s IGP
文摘Perrhenate(ReO4-) was used as nonradioactive surrogate for the radionuclide pertechnetate(99TcO-4) to investigate the potential of using starch-stabilized zero valent iron(ZVI) nanoparticles for reductive immobilization of pertechnetate in soil and groundwater.Batch kinetic tests indicated that the starch-stabilized ZVI nanoparticles were able to reductively remove ～96% of perrhenate(10 mg/L) from water within 8 h.XRD analyses confirmed that ReO 2 was the reduction product.A pseudo-first-order kinetic model was able to interpret the kinetic data,which gave a pseudo first order rate constant(kobs) value of 0.43h-1 at pH 6.9 and room temperature(25℃).Increasing solution pH up to 8 progressively increased the reaction rate.However,highly alkaline pH(10) resulted in much inhibited reaction rate.Consequently,the optimal pH range was identified to be from 7 to 8.Increasing solution temperature from 15 to 45℃ increased k obs from 0.38 to 0.53 h-1.The classical Arrhenius equation was able to interpret the temperature effect,which gave a low activation energy value of 7.61 kJ/mol.When the ReO-4-loaded loess was treated with the stabilized nanoparticles suspension([Fe]=560 mg/L),the water leachable ReO-4 was reduced by 57% and nearly all eluted Re was in the form of ReO2.This finding indicates that starch-stabilized ZVI nanoparticles are promising for facilitating in situ immobilization of ReO-4 in soil and groundwater.
