Unified Metallic Catalyst Aging Strategy and Implications for Water Treatment

Chung Seop Lee, Sujin Guo, Hojung Rho, Juliana Levi, Sergi Garcia-Segura, Michael S. Wong, Jorge Gardea-Torresdey, Paul Westerhoff

Research output: Contribution to journalArticlepeer-review

Abstract

Heterogeneous catalysis holds great promise for oxidizing or reducing a range of pollutants in water. A well-recognized, but understudied, barrier to implement catalytic treatment centers around fouling or aging over time of the catalyst surfaces. To better understand how to study catalyst fouling or aging, we selected a representative bimetallic catalyst (Pd-In supported on Al2O3), which holds promise to reduce nitrate to innocuous nitrogen gas byproducts upon hydrogen addition, and six model solutions (deionized water, sodium hypochlorite, sodium borohydride, acetic acid, sodium sulfide, and tap water). Our novel aging experimental apparatus permitted single passage of each model solution, separately, through a small packed-bed reactor containing replicate bimetallic catalyst "beds"that could be sacrificed weekly for off-line characterization to quantify impacts of fouling or aging. The composition of the model solutions led to the following gradual changes in surface composition, morphology, or catalytic reactivity: (i) formation of passivating species, (ii) decreased catalytic sites due to metal leaching under acid conditions or sulfide poisoning, (iii) dissolution and/or transformation of indium, (iv) formation of new catalytic sites by the introduction of an additional metallic element, and (v) oxidative etching. The model solution water chemistry captured a wide range of conditions likely to be encountered in potable or industrial water treatment. Aging-induced changes altered catalytic activity and provided insights into potential strategies to improve long-term catalyst operations for water treatment.

Original languageEnglish (US)
Pages (from-to)11284-11293
Number of pages10
JournalEnvironmental Science and Technology
Volume55
Issue number16
DOIs
StatePublished - Aug 17 2021

Keywords

  • alumina-supported Pd-In
  • bimetallic catalyst
  • catalyst aging
  • deactivation

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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