Enhanced electron transfer pathway of zero-valent iron particles immobilized on coconut shell derived carbon for prolonged Cr(VI) removal

Peng Yu, Juan Tan, Zhiguo Wang, Chun Zhang, Qiongchao Wang, Keming Zhu, Chao Peng, Xinxin Xiao, Wei Huang

Research output: Contribution to journalJournal articleResearchpeer-review

1 Citation (Scopus)

Abstract

Immobilizing zero-valent iron (ZVI) with modulated structure and good dispersibility is of great potential for the elimination of Cr(VI) in contaminated water or soil, but exploring how the support facilitate and prolong the removal of Cr(VI) by ZVI in terms of the electron transfer is inadequate. Coconut shell derived carbon could be promising for Cr(VI) removal due to the features of large specific surface area and porosity. Accordingly, ZVI particles are dispersed into low-cost and scalable coconut shell derived carbon (CSC) matrix uniformly in this study, with enhanced contact area and interaction of ZVI with CSC for effective elimination of Cr(VI). The optimal ZVI/CSC-0.65 demonstrates an equilibrium adsorption capacity of 307.8mg/g and long-life Cr(VI) cleanup ability over 144h. The interface reaction mechanism between ZVI/CSC and Cr contaminant have been systematically studied by various techniques including XRD, SEM/TEM and XPS, etc. ZVI’s aggregation and passivation in ZVI/CSC-0.65 have been greatly alleviated. Further analysis by Tafel polarization and DFT computation suggests ZVI/CSC-0.65 undergoes fast electron transfer, with a much higher adsorption energy (-2.90eV) than that of pristine ZVI (-0.63eV). The Bader charge analysis demonstrates that there is 4.40 |e| charge transferring the ZVI to the carbon, encouraging the Cr(VI) adsorption. A micro-battery based mechanism is proposed which provides an additional electron transfer pathway in ZVI/CSC for long-term Cr(VI) removal.
Original languageEnglish
Article number132863
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume682
Pages (from-to)132863
Number of pages1
ISSN0927-7757
DOIs
Publication statusPublished - 5 Feb 2024

Keywords

  • Zero-valent iron
  • Coconut shell derived carbon
  • Long-life Cr(VI) removal
  • DFT computation
  • Enhanced electron transfer pathway

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