Uranium-contaminated soil can be effectively decontaminated through acid leaching; however, this process process generates significant amounts of radioactive wastewater. Therefore, developing efficient methods to remove uranium from wastewater is essential to minimize radioactive waste generation. This study investigates the applicability of various precipitation methods for uranium removal from acidic wastewater produced during soil-washing processes. Three methods were evaluated: metal hydroxide (M–OHx) co-precipitation, uranium peroxide (UO4) precipitation, and uranium phosphate (KUO2PO4) precipitation. The M–OHx precipitation method removes uranium by precipitating excess metal ions in wastewater by adjusting the pH. This method is easy to use and has a high removal efficiency. The UO4 and KUO2PO4 precipitation methods involve adding reagents to precipitate uranium in the mineral phase. They enable selective uranium separation and further volume reduction. In the results, M–OHx and KUO2PO4 precipitation methods remove uranium to less than 1 mg∙L−1 within 2 h, demonstrating superior capabilities compared to UO4 precipitation. The optimal method is different depended on the management strategy for the recovered uranium. The M–OHx precipitation method was suitable for permanent disposal, whereas KUO2PO4 could be recycled. Based on these findings, guidelines for the effective treatment of wastewater containing uranium from the soil-washing process can be established.

1. Introduction
2. Experimental
    2.1 Simulated Soil-Washed (SSW) Wastewater
    2.2 Precipitation Experiments
    2.3 Analysis Method
3. Results and Discussion
    3.1 Uranium Removal Efficiency
    3.2 Characterization of M–OHx Co-precipitationWith Different Fe Concentrations
    3.3 Evaluation of KUO2PO4 Precipitation WithDifferent PO43− Concentrations
4. Conclusions
Conflict of Interest
Acknowledgements
REFERENCES

• Maengkyo Oh(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea) Corresponding author
• Jun-Young Jung(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea)
• Keunyoung Lee(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea)
• Hee-Chul Eun(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea)
• Byung-Moon Jun(Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Republic of Korea)