Novel, low-cost Fe^0/ZSM-5-based particles and porous tablets were prepared by a ballmilling method and used for the removal of Pb^(2+) in solution. Solid-phase characterization by scanning electron microscopy coupled...Novel, low-cost Fe^0/ZSM-5-based particles and porous tablets were prepared by a ballmilling method and used for the removal of Pb^(2+) in solution. Solid-phase characterization by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy(SEMEDS) and transmission electron microscopy(TEM) revealed that the Fe0 microparticles were evenly loaded and tightly immobilized on the surface of ZSM-5 because of the extrusion/welding impact during ball-milling. For different Pb^(2+) concentrations, batch experiments indicated that the removal of Pb^(2+) increased with the decline of dissolved Fe2+and p H value in the solution for particles; opposite results were obtained for the tablets. The differences in the contact between both materials and Pb^(2+) were the main factor controlling Pb^(2+) removal in the solution. Investigation into the effect of initial p H value revealed that high p H reduced the number of electrons released from Fe corrosion. Consequently, low levels of removed Pb^(2+) and dissolved Fe^(2+) were synchronously observed. Also, simulated electroplating wastewater was treated using the prepared particles and porous tablets,and the removal order of Pb^(2+) > Cr^(6+)> Cu^(2+)≈ Cd^(2+) was observed. The Fe^0/ZSM-5 particles and tablets prepared through ball-milling show potential as materials for treatment of Pb^(2+) and other toxic metals.展开更多
Although widely used in permeation reaction barrier(PRB)for strengthening the removal of various heavy metals,zero-valent iron(ZVI)is limited by various inherent drawbacks,such as easy passivation and poor electron tr...Although widely used in permeation reaction barrier(PRB)for strengthening the removal of various heavy metals,zero-valent iron(ZVI)is limited by various inherent drawbacks,such as easy passivation and poor electron transfer.As a solution,a synergistic system with PRB and electrokinetics(PRB-EK)was established and applied for the efficient removal of Cr(Ⅵ)-contaminated groundwater.As the filling material of PRB,ZVI/Fe_(3)O_(4)/activated carbon(ZVI/Fe_(3)O_(4)/AC)composites were synthesized by ball milling and thermal treatment.A series of continuous flow column experiments and batch tests was conducted to evaluate the removal efficiency of Cr(Ⅵ).Results showed that the removal efficiency of Cr(Ⅵ)remained above 93%even when the bed volume(BV)reached 2000 under the operational parameters(iron/AC mass ratio,2:1;current,5 m A).The mechanism of Cr(Ⅵ)removal by the PRB-EK system was revealed through field emission scanning electron microscopy images,X-ray diffraction,X-ray photoelectron spectroscopy,Fe^(2+) concentration,and redox potential(E h)values.The key in Cr(Ⅵ)reduction was the Fe^(2+)/Fe^(3+) cycle driven by the surface microelectrolysis of the composites.The application of an externally supplied weak direct current maintained the redox process by enhancing the electron transfer capability of the system,thereby prolonging the column lifetime.Cr(Ⅵ)chemical speciation was determined through sequential extraction,verifying the stability and safety of the system.These findings provide a scientific basis for PRB design and the in-situ remediation of Cr(Ⅵ)-contaminated groundwater.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51378180,21677162)
文摘Novel, low-cost Fe^0/ZSM-5-based particles and porous tablets were prepared by a ballmilling method and used for the removal of Pb^(2+) in solution. Solid-phase characterization by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy(SEMEDS) and transmission electron microscopy(TEM) revealed that the Fe0 microparticles were evenly loaded and tightly immobilized on the surface of ZSM-5 because of the extrusion/welding impact during ball-milling. For different Pb^(2+) concentrations, batch experiments indicated that the removal of Pb^(2+) increased with the decline of dissolved Fe2+and p H value in the solution for particles; opposite results were obtained for the tablets. The differences in the contact between both materials and Pb^(2+) were the main factor controlling Pb^(2+) removal in the solution. Investigation into the effect of initial p H value revealed that high p H reduced the number of electrons released from Fe corrosion. Consequently, low levels of removed Pb^(2+) and dissolved Fe^(2+) were synchronously observed. Also, simulated electroplating wastewater was treated using the prepared particles and porous tablets,and the removal order of Pb^(2+) > Cr^(6+)> Cu^(2+)≈ Cd^(2+) was observed. The Fe^0/ZSM-5 particles and tablets prepared through ball-milling show potential as materials for treatment of Pb^(2+) and other toxic metals.
基金Acknowledgements This work was financially supported by the National Natural Science Foundation of China （No： 51378180）, the Technology Department of the Henan Science and Technology Fund Project （No： 142102210457）, and the Fundamental Research Funds for the Central Universities （No： 30916014102）.
基金Acknowledgements We would like to acknowledge all of the participators who collected HWI ash samples for this study from both the Beijing and Nanjing sites. This work was financially supported by the National Natural Science Foundation of China （Grant No. 51378180）, the Technology Department of the Henan Science and Technology Fund Project （Nos. 142102210457 and 142102210456）, and the Fundamental Research Funds for the Central Universities （No. 30916014102）.
基金financial support from the National Natural Science Foundation of China(Nos.21906044 and 21477034)the Key Science and Technology Program of Henan Province,China(No.132102210129)+3 种基金the Basic Scientific and Technological Frontier Project of Henan Province(No.162300410046)the Innovation Scientists and Technicians Troop Construction Projects of Henan Province,the Scientific Research Foundation from Soochow University(No.Q416000117)the Technology Department of the Henan Science and Technology Fund Project(No.202102310603)the Cultivating National Scientific Research Project Funds,Henan Normal University(No.5101219170804)。
文摘Although widely used in permeation reaction barrier(PRB)for strengthening the removal of various heavy metals,zero-valent iron(ZVI)is limited by various inherent drawbacks,such as easy passivation and poor electron transfer.As a solution,a synergistic system with PRB and electrokinetics(PRB-EK)was established and applied for the efficient removal of Cr(Ⅵ)-contaminated groundwater.As the filling material of PRB,ZVI/Fe_(3)O_(4)/activated carbon(ZVI/Fe_(3)O_(4)/AC)composites were synthesized by ball milling and thermal treatment.A series of continuous flow column experiments and batch tests was conducted to evaluate the removal efficiency of Cr(Ⅵ).Results showed that the removal efficiency of Cr(Ⅵ)remained above 93%even when the bed volume(BV)reached 2000 under the operational parameters(iron/AC mass ratio,2:1;current,5 m A).The mechanism of Cr(Ⅵ)removal by the PRB-EK system was revealed through field emission scanning electron microscopy images,X-ray diffraction,X-ray photoelectron spectroscopy,Fe^(2+) concentration,and redox potential(E h)values.The key in Cr(Ⅵ)reduction was the Fe^(2+)/Fe^(3+) cycle driven by the surface microelectrolysis of the composites.The application of an externally supplied weak direct current maintained the redox process by enhancing the electron transfer capability of the system,thereby prolonging the column lifetime.Cr(Ⅵ)chemical speciation was determined through sequential extraction,verifying the stability and safety of the system.These findings provide a scientific basis for PRB design and the in-situ remediation of Cr(Ⅵ)-contaminated groundwater.
