US EPA

3842059 

Journal Article 

Ship-in-a-bottle CMPO in MIL-101(Cr) for selective uranium recovery from aqueous streams through adsorption 

De Decker, J; Folens, K; De Clercq, J; Meledina, M; Van Tendeloo, G; Du Laing, G; Van Der Voort, P 

2017 

Yes 

Journal of Hazardous Materials
ISSN: 0304-3894
EISSN: 1873-3336 

335 

1-9 

English 

28414943 

10.1016/j.jhazmat.2017.04.029 

WOS:000402948600001 

Mesoporous MIL-101(Cr) is used as host for a ship-in-a-bottle type adsorbent for selective U(VI) recovery from aqueous environments. The acid-resistant cage-type MOF is built in-situ around N,N-Diisobutyl-2-(octylphenylphosphoryl)acetamide (CMPO), a sterically demanding ligand with high U(VI) affinity. This one-step procedure yields an adsorbent which is an ideal compromise between homogeneous and heterogeneous systems, where the ligand can act freely within the pores of MIL-101, without leaching, while the adsorbent is easy separable and reusable. The adsorbent was characterized by XRD, FTIR spectroscopy, nitrogen adsorption, XRF, ADF-STEM and EDX, to confirm and quantify the successful encapsulation of the CMPO in MIL-101, and the preservation of the host. Adsorption experiments with a central focus on U(VI) recovery were performed. Very high selectivity for U(VI) was observed, while competitive metal adsorption (rare earths, transition metals...) was almost negligible. The adsorption capacity was calculated at 5.32mg U/g (pH 3) and 27.99mg U/g (pH 4), by fitting equilibrium data to the Langmuir model. Adsorption kinetics correlated to the pseudo-second-order model, where more than 95% of maximum uptake is achieved within 375min. The adsorbed U(VI) is easily recovered by desorption in 0.1M HNO3. Three adsorption/desorption cycles were performed.