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CMPO-Functionalized Silica Sorbents for pH-Tunable Separation and Enrichment of Rare-Earth Elements from
Ahmed K Sakr1, Sai Praneeth1, Preetom K Roy1
1Department of Civil and Environmental Engineering, Wayne State University, 5050 Anthony Wayne Drive, Detroit, Michigan 48202, United States.
ACS Sustainable Chemistry & Engineering
|March 6, 2026
Summary
A novel CMPO-functionalized silica sorbent offers efficient separation of rare-earth elements (REEs). This pH-tunable material enables selective REE recovery from complex solutions with high enrichment factors and water-elutable properties.
Area of Science:
- Materials Science
- Inorganic Chemistry
- Separation Science
Background:
- Rare-earth elements (REEs) are vital for modern technologies but challenging to separate due to similar chemical properties.
- Octyl-phenyl-N,N-diisobutyl carbamoyl methyl phosphine oxide (CMPO) is a ligand effective for actinide and lanthanide extraction.
Purpose of the Study:
- To develop a pH-tunable CMPO-functionalized silica sorbent for selective REE separation.
- To evaluate the sorbent's performance in complex aqueous matrices and real-world samples.
Main Methods:
- Synthesis and characterization of CMPO-functionalized silica gel using BET, SEM, and XPS.
- Performance evaluation with synthetic multi-element solutions and phosphate rock leachate.
- Packed-bed column studies to assess enrichment and elution capabilities.
Main Results:
- The sorbent demonstrated selective REE separation and successful elution with ultrapure water, controlled by pH.
- Packed-bed column studies achieved a 20-fold increase in REE mass fraction and up to 30-fold enrichment of neodymium.
- Adsorption followed Langmuir isotherm behavior and pseudo-second-order kinetics, with a ligand:REE(III) ratio of 4:1.
Conclusions:
- CMPO-functionalized silica is a promising platform for sustainable REE recovery.
- The material offers selectivity, water-elutability, and low chemical input requirements.
- This approach is suitable for recovering REEs from environmental and industrial sources.
Keywords:
chelating ligandscritical mineralsmesoporous silicaphosphate rock fertilizerseparationsolid−liquid extractionMore Related Videos
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