• Soil Washing Technology for Sr and Cs-contaminated Soil Near Nuclear Power Plants using Calcium and Potassium Based Solutions
  • Hojae Song1·Kyoungphile Nam1*

  • 1Department of Civil and Environmental Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, Korea

  • 칼슘 및 칼륨 용액을 이용한 원자력발전소 주변 스트론튬과 세슘 오염토양 세척기술 연구
  • 송호재1·남경필1*

  • 1서울대학교 건설환경공학부

  • This article is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Calcium (Ca) and potassium (K) were introduced to remove Sr and Cs in soil, respectively. Four factor and three level Box-Bhenken design was employed to determine the optimal washing condition of Ca- and K-based solutions, and the ranges tested were 0.1 to 1 M of Ca or K, L/S ratio of 5 to 20, washing time of 0.5 to 2 h, and pH of 2 to 7. The optimal washing condition determined was 1 M of Ca or K, L/S ratio of 20, washing time of 1 h, and pH of 2, and Ca-based and K-based solutions showed 68 and 81% removal efficiency for Sr and Cs, respectively in soil. For comparison, widely used conventional washing agents such as 0.075 M EDTA, 0.01 M citric acid, 0.01 M oxalic acid, and 0.05 M phosphoric acid were tested, and they showed 25 to 30% of Sr and Cs removal efficiency. Tessier sequential extraction was employed to identify the changes in chemical forms of Sr and Cs during the washing. In contrast to the conventional washing agents, Ca-based and K-based solutions were able to release relatively strongly bound forms of Sr and Cs such as Fe/Mn-oxide and organic matter bound forms, suggesting the involvement of direct substitution mechanism, probably due to the physicochemical similarities between Sr-Ca and Cs-K.


Keywords: Soil washing, Box-Bhenken design, Substitution, Physicochemical similarity

This Article

  • 2022; 27(2): 76-86

    Published on Apr 30, 2022

  • 10.7857/JSGE.2022.27.2.076
  • Received on Feb 21, 2022
  • Revised on Mar 2, 2022
  • Accepted on Apr 11, 2022

Correspondence to

  • Kyoungphile Nam
  • Department of Civil and Environmental Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, Korea

  • E-mail: kpnam@snu.ac.kr