본문 바로가기
  • Home
Basic Search

Mineralization of oxalic acid by underwater non-thermal plasma: TOC removal and 13C isotope tracer

  • Carbon Letters
  • Abbr : Carbon Lett.
  • 2026, 36(1), pp.201~211
  • DOI : 10.1007/s42823-025-01007-0
  • Publisher : Korean Carbon Society
  • Research Area : Natural Science > Natural Science General > Other Natural Sciences General
  • Received : October 10, 2025
  • Accepted : December 20, 2025
  • Published : February 1, 2026

Shin Ki-baek 1,  Lee Heejae 2,  Yang Geon Woo 3,  Hong Yong Cheol 4,  HONG DAE-SEOK 1,  Kim Kangil 4,  Cho Gyuseong 1

1한국원자력연구원
2전북대학교
3한국 핵융합 에너지연구소
4한국과학기술연구원

Accredited

ABSTRACT

This study evaluates underwater non-thermal plasma (UNTP) as a reagent-free process for the complete mineralization of oxalic acid, a major chelating agent in nuclear decontamination effluents. Quantitative assessment was based on total organic carbon (TOC) removal and stable carbon isotope tracing with uniformly labeled ¹³C-oxalic acid. TOC and ion chromatography (IC) analyses demonstrated complete mineralization within 60 min at ≤ 300 ppm (k = 0.120, 0.100, 0.042 min⁻¹; t₉₀ = 19.2, 23.0, 55.0 min), whereas at 450 ppm partial mineralization remained (TOC 25.4 mg C/L after 60 min). At higher concentrations (1000–2000 ppm), TOC removal was restricted to 25–57% with rate constants decreasing to 0.008 and 0.003 min⁻¹ (t₉₀ = 288, 767 min); at 3000 ppm, reaction nearly stagnated (k = 0.0009 min⁻¹; t₉₀ ≈ 2558 min). Energy yield peaked at low/intermediate concentrations (0.9–1.3 g-C kWh⁻¹; 1.1 g-C kWh⁻¹ at 450 ppm) but declined to 0.9, 0.3, and 0.2 g-C kWh⁻¹ at 1000, 2000, and 3000 ppm. Mechanistic profiling showed that both glyoxylic and formic acids remained below the method detection limits (LOD) throughout the treatment period, supporting that a predominantly direct mineralization pathway to CO₂ was operative. Critically, ¹³C tracer experiments (300 ppm, 60 min) yielded δ¹³C = + 5702‰ (~ 7.0 atom % ¹³C), confirming the presence of substrate-derived carbon in the evolved CO₂. No solids or carbonate byproducts were detected, consistent with a nearly closed carbon balance. Bulk temperatures remained ≤ 40 °C under all conditions, confirming non-thermal operation. These findings establish TOC-based kinetics and isotopic evidence of oxalic acid mineralization, define a practical operating window (≤ 2000 ppm), and support UNTP as a sustainable route for treating chelating agents in decontamination effluents.

Statistics

  • 3 Viewed
  • 0 Downloaded

Tools

Issue List

Citation status

* References for papers published after 2024 are currently being built.

Basic Search Advanced Search