TY - JOUR
T1 - Recovery of rare-earth and radioactive elements from contaminated water through precipitation
T2 - A review
AU - Jun, Byung Moon
AU - Kim, Hak Hyeon
AU - Rho, Hojung
AU - Seo, Jiwon
AU - Jeon, Jin Woo
AU - Nam, Seong Nam
AU - Min Park, Chang
AU - Yoon, Yeomin
N1 - Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/11/1
Y1 - 2023/11/1
N2 - Recovery of rare-earth elements (REEs) and radioactive elements have become an important issue because they are precious materials for economic growth, environmental protection, and national security. This study provides a comprehensive review of precipitation processes for the recovery of REEs and radioactive elements according to precipitant type and precipitation mechanism. The optimal recovery performance of these approaches varies with several water quality factors, namely, solution pH, dissolved oxygen, temperature, the presence of co-ions, ionic strengths, the initial concentration of target elements, and the presence of organic substances (e.g., humic acids). For instance, an interesting phenomenon was observed when U(VI) was reductively precipitated by ferrous ion under high-O2 conditions, since precipitated U(IV) on iron surfaces reoxidized during groundwater remediation when it is exposed to O2. These optimal recovery performance and its precipitation mechanisms are clarified via three main characterization approaches: (i) optical and electron microscopy approaches, (ii) X-ray diffraction–based approaches, and (iii) spectroscopy approaches. These characterization methods are complementary and can enhance the reliability of precipitation mechanisms. Lastly, a concise overview is provided regarding the complex systems and potential research challenges of the precipitation process for the recovery of REEs and radioactive elements, based on the fact that complex recovery systems could be optimized by consideration of mass-balance calculations, economical assessment, timescale, and redox sources from an engineering perspective.
AB - Recovery of rare-earth elements (REEs) and radioactive elements have become an important issue because they are precious materials for economic growth, environmental protection, and national security. This study provides a comprehensive review of precipitation processes for the recovery of REEs and radioactive elements according to precipitant type and precipitation mechanism. The optimal recovery performance of these approaches varies with several water quality factors, namely, solution pH, dissolved oxygen, temperature, the presence of co-ions, ionic strengths, the initial concentration of target elements, and the presence of organic substances (e.g., humic acids). For instance, an interesting phenomenon was observed when U(VI) was reductively precipitated by ferrous ion under high-O2 conditions, since precipitated U(IV) on iron surfaces reoxidized during groundwater remediation when it is exposed to O2. These optimal recovery performance and its precipitation mechanisms are clarified via three main characterization approaches: (i) optical and electron microscopy approaches, (ii) X-ray diffraction–based approaches, and (iii) spectroscopy approaches. These characterization methods are complementary and can enhance the reliability of precipitation mechanisms. Lastly, a concise overview is provided regarding the complex systems and potential research challenges of the precipitation process for the recovery of REEs and radioactive elements, based on the fact that complex recovery systems could be optimized by consideration of mass-balance calculations, economical assessment, timescale, and redox sources from an engineering perspective.
KW - Precipitation
KW - Rare-earth and radioactive elements
KW - Recovery
KW - Water treatment
UR - http://www.scopus.com/inward/record.url?scp=85172696031&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2023.146222
DO - 10.1016/j.cej.2023.146222
M3 - Review article
AN - SCOPUS:85172696031
SN - 1385-8947
VL - 475
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 146222
ER -