Trichloroethene (TCE) hydrodechlorination by Ni–Fe nanoparticles: Influence of aqueous anions on catalytic pathways

Yanlai Han, Changjie Liu, Juske Horita, Weile Yan

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Amending bulk and nanoscale zero-valent iron (ZVI) with catalytic metals significantly accelerates hydrodechlorination of groundwater contaminants such as trichloroethene (TCE). The bimetallic design benefits from a strong synergy between Ni and Fe in facilitating the production of active hydrogen for TCE reduction, and it is of research and practical interest to understand the impacts of common groundwater solutes on catalyst and ZVI functionality. In this study, TCE hydrodechlorination reaction was conducted using fresh Ni–Fe bimetallic nanoparticles (Ni–Fe BNPs) and those aged in chloride, sulfate, phosphate, and humic acid solutions with concurrent analysis of carbon fractionation of TCE and its daughter products. The apparent kinetics suggest that the reactivity of Ni–Fe BNPs is relatively stable in pure water and chloride or humic acid solutions, in contrast to significant deactivation observed of Pd–Fe bimetallic particles in similar media. Exposure to phosphate at greater than 0.1 mM led to a severe decrease in TCE reaction rate. The change in kinetic regimes from first to zeroth order with increasing phosphate concentration is consistent with consumption of reactive sites by phosphate. Despite severe kinetic effect, there is no significant shift in TCE 13C bulk enrichment factor between the fresh and the phosphate-aged particles. Instead, pronounced retardation of TCE reaction by Ni–Fe BNPs in deuterated water (D2O) points to the importance of hydrogen spillover in controlling TCE reduction rate by Ni–Fe BNPs, and such process can be strongly affected by groundwater chemistry.

Original languageEnglish
Pages (from-to)404-413
Number of pages10
JournalChemosphere
Volume205
DOIs
StatePublished - Aug 2018

Keywords

  • Aqueous deactivation
  • Bimetallic nanoparticle
  • Hydrodechlorination
  • Kinetic isotope effect
  • Ni–Fe
  • Trichloroethene

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