An Efficient Sulfuric Acid- and Hydrazine-based Process for Recycling Wastewater Generated From U(VI)-Contaminated Soil-Washing

• Published in: Journal of nuclear fuel cycle and waste technology (Online) Vol. 22; no. 2; pp. 159 - 171
• Main Authors: Lee, Hyun-Kyu, Jun, Byung-Moon, Kim, Tack-Jin, Park, Sungbin, Choi, Seonggyu, Jung, Jun-Young, Eun, Hee-Chul
• Format: Journal Article
• Language: English
• Published: 한국방사성폐기물학회 01.06.2024
• Subjects: 원자력공학; Water recycling; Soil-washing; Hydrazine decomposition; Uranium precipitation; Wastewater treatment
• ISSN: 1738-1894; 2288-5471
• DOI: 10.7733/jnfcwt.2024.020

This study aimed to develop an efficient recycling process for wastewater generated from soil-washing used to remediate uranium (U(VI))-contaminated soil. Under acidic conditions, U(VI) ions leached from the soil were precipitated and separated through neutralization using hydrazine (N2H4). N2H4, employed as a pH adjuster, was decomposed into nitrogen gas (N2), water (H2O), and hydrogen ions (H+) by hydrogen peroxide (H2O2). The residual N2H4 was precipitated when the pH was adjusted using sulfuric acid (H2SO4) to recycle the wastewater in the soil-washing process. This purified wastewater was reused in the soil-washing process for a total of ten cycles. The results confirmed that the soil-washing performance for U(VI)-contaminated soil was maintained when using recycled wastewater. All in all, this study proposes an efficient recycling process for wastewater generated during the remediation of U(VI)-contaminated soil.