Journal
JOURNAL OF HAZARDOUS MATERIALS
Volume 409, Issue -, Pages -Publisher
ELSEVIER
DOI: 10.1016/j.jhazmat.2020.124925
Keywords
Calcite decomposition; Calcination; Red mud; Uranium; Electrostatic attraction
Categories
Funding
- National Natural Science Foundation of China [41877290, 22076034, 51708143]
- Foundation of Department of Education of Guangdong Province of China [2018KTSCX176]
- Project of Guangdong Provincial Key Laboratory of Radioactive Contamination Control and Resources [2017B030314182]
- Guangzhou University Intramural Scientific Research Project [YG2020012]
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This study produced macroporous iron and carbon combined calcined red mud (ICRM) and carbon calcined red mud (CRM) through calcination in the range of 500-800 degrees C, revealing advantageous performances with stable U adsorption capacities. The main adsorption mechanisms of ICRM are surface electrostatic attraction, physical adsorption by porous structure, and chemical adsorption by active Al and Fe components. Overall, ICRM offers theoretical guidances to radioactive drainage management and red mud reuse by exhibiting superior U adsorption capacity and positive potential charges under acidic conditions.
Iron-rich red mud is a potent radioactive drainage treatment material. However, the calcite in red mud attenuates its U adsorption capacity by restricting U adsorption onto adsorbent; it captures U as a dissociative complex in aqueous systems. This study produced macroporous iron and carbon combined calcined red mud (ICRM) and carbon calcined red mud (CRM) through calcination in the range of 500-800 degrees C. XRD results revealed that both series generated advantageous magnetite and calcite were fully decomposed. SEM and batch experiments highlighted ICRM calcined at 600 degrees C has more stable and favorable performance. The components of post-adsorption ICRM remained active, as demonstrated by FT-IR results. Additionally, ICRM@600 displayed superior U adsorption capacity (59.45 mg/g) than did all red mud adsorbents from our previous research. Zeta-potential results revealed ICRM has positive potential charges in acidic conditions, indicating it adsorbs U(VI) ions via electrostatic attraction. The main adsorption mechanisms of ICRM are surface electrostatic attraction, physical adsorption by porous structure, and chemical adsorption by active Al and Fe components. In application, ICRM@600 obtained a 82.20% U adsorption ratio in uranium mine pit drainage. Overall, this study offers theoretical guidances to radioactive drainage management and red mud reuse.
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