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您的检索式：作者名="Kenneth C.Carroll"
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| 1 | Mechanistic insight into Cr(Ⅵ)retention by Si-containing ferrihydrite显示文摘Hexavalent chromium[Cr(Ⅵ)]causes serious harm to the environment due to its high toxicity,solubility,and mobility.Ferrihydrites(Fh)are the main adsorbent and trapping agent of Cr(Ⅵ)in soils and aquifers,and they usually coexist with silicate(Si),forming Si-containing ferrihydrite(Si-Fh)mixtures.However,the mechanism of Cr(Ⅵ)retention by Si-Fh mixtures is poorly understood.In this study,the behaviors and mechanisms of Cr(Ⅵ)adsorption onto Si-Fh with different Si/Fe molar ratios was investigated.Transmission electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and other techniques were used to characterize Si-Fh and Cr(Ⅵ)-loading of Si-Fh.The results show that specific surface area of Si-Fh increases gradually with increasing Si/Fe ratios,but Cr(Ⅵ)adsorption on Si-Fh decreases with increasing Si/Fe ratios.This is because with an increase in Si/Fe molar ratio,the point of zero charge of Si-Fh gradually decreases and electrostatic repulsion between Si-Fh and Cr(Ⅵ)increases.However,the complexation of Cr(Ⅵ)is enhanced due to the increase in adsorbed hydroxyl(A-OH-)on Si-Fh with increasing Si/Fe molar ratio,which partly counteracts the effect of the electrostatic repulsion.Overall,the increase in the electrostatic repulsion has a greater impact on adsorption than the additional complexation with Si-Fh.Density functional theory calculation further supports this observation,showing the increases in electron variation of bonding atoms and reaction energies of inner spherical complexes with the increase in Si/Fe ratio. | Ying Hu Qiang Xue Honghan Chen Huaming Guo Kenneth C.Carroll Song Wang | 2024 | Journal of Environmental Sciences2024，，5： | 0 |
| 2 | Cadmium removal mechanistic comparison of three Fe-based nanomaterials: Water-chemistry and roles of Fe dissolution显示文摘Cadmium(Cd)is a common toxic heavy metal in the environment.Taking Cd(II)as a target contaminant,we systematically compared the performances of three Fe-based nanomaterials(nano zero valent iron,nZVI;sulfidated nZVI,S-nZVI;and nano FeS,nFeS)for Cd immobilization under anaerobic conditions.Effects of nanomaterials doses,initial pH,co-existing ions,and humic acid(HA)were examined.Under identical conditions,at varied doses or initial pH,Cd(II)removal by three materials followed the order of S-nZVI>nFeS>nZVI.At pH 6,the Cd(II)removal within 24 hours for S-nZVI,nFeS,and nZVI(dose of 20 mg/L)were 93.50%,89.12%and 4.10%,respectively.The fast initial reaction rate of nZVI did not lead to a high removal capacity.The Cd removal was slightly impacted or even improved with co-existing ions(at 50 mg/L or 200 mg/L)or HA(at 2 mg/L or 20 mg/L).Characterization results revealed that nZVI immobilized Cd through coprecipitation,surface complexation,and reduction,whereas the mechanisms for sulfidated materials involved replacement,coprecipitation,and surface complexation,with replacement as the predominant reaction.A strong linear correlation between Cd(II)removal and Fe(II)dissolution was observed,and we proposed a novel pseudo-second-order kinetic model to simulate Fe(II)dissolution. | Xiaoge Huang Lihao Chen Ziqi Ma Kenneth C.Carroll Xiao Zhao Zailin Huo | 2022 | Frontiers of Environmental Science & Engineering2022，16，12： | 0 |
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