AI Article Synopsis

  • * Characterization of PA-ZVI indicates an increased surface availability of iron (Fe(0) and Fe(II)), promoting efficient electron transfer and significantly improving chromium reduction performance, with reaction rates and adsorption capacity far exceeding those of regular ZVI.
  • * Theoretical calculations reveal that PA aids in better adsorption of Cr(VI) on ZVI, resulting in a 100% conversion rate and effective performance across varying pH levels and ion conditions

Article Abstract

Electron transfer of zero-valent iron (ZVI) is significantly impeded by its oxide layer, and limiting its removal of pollutants. In this study, 2-picolinic acid (PA) and ZVI were co-ball milled to improve electron transfer in ZVI (PA-ZVI), and used for the removal of heavy metal Cr(VI). Characterization analysis showed that the presence of electron-rich groups on the surface of PA-ZVI promoted the transfer of electrons from the Fe(0) core to the surface, and the surface Fe(0) and Fe(II) contents increased from 1.1 % to 6.3 % and from 60.2 % to 72.9 %, respectively, effectively reducing Cr(VI) through an electron transfer mechanism. Theoretical calculations showed that the modification of PA enhanced the adsorption of Cr(VI) on the ZVI surface, and the adsorption energy decreased from -3.561 eV to -5.119 eV. PA-ZVI showed strong advantages in the removal of Cr(VI), with a reaction rate constant and adsorption capacity 17 and 13 times that of ZVI, respectively, and a conversion rate of 100 %. Moreover, PA-ZVI showed excellent performance over a wide pH range (3-10) and under different coexisting ions, while being cost-effective and having low environmental risks. This study explored the relationship between ZVI surface modification and performance, and provided new insights into the modification of ZVI using small molecule oxygen-containing organic acids.

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Source
http://dx.doi.org/10.1016/j.jhazmat.2024.136670DOI Listing

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