Determining the kinetic constants leading to mineralization of dilute carbamazepine and estradiol-containing solutions under continuous supercritical water oxidation conditions

Yaron Aviezer*, Ori Lahav

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Continuous subcritical and supercritical water oxidation experiments were conducted on dilute carbamazepine- and estradiol-containing synthetic solutions used to simulate the removal of model emerging pollutants from secondary municipal effluents. The operating conditions comprised 340–500 °C, retention time of 24–453 s and a stoichiometric oxidant ratio (O.C.) between 4 and 64. The transformation of the various species was determined at the outlet and by modeling a segmented non-isothermal reaction system. Four empirical power law kinetic models were established to represent both the pollutants' degradation and TOC removal efficiencies, using nonlinear multiple regression coupled with bootstrapping and K-fold cross-validation. The mineralization and degradation models for both pollutants yielded a R2 of 67–80.5% vs. the experimental results. Discussion on the various model assumptions revealed that attributing full model deviations to the constant oxygen concentration or to the laminar reactor flow, yielded a deviation of 6% and 15% in the removal efficiencies, respectively. However, the expected deviation of the models was lower than 0.32% at conditions leading to (almost) full mineralization (45–60 s, 480–500 °C and O.C.s of 5–10). The methodologies developed in the study are useful for interpreting future results obtained from SCWO of actual secondary effluent solutions.

Original languageEnglish
Article number126797
JournalJournal of Hazardous Materials
Volume422
DOIs
StatePublished - 15 Jan 2022
Externally publishedYes

Keywords

  • 17β-Estradiol
  • Carbamazepine
  • Effluent RO retentate
  • SCWO

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