Nano-MOF⁺ Technique for Efficient Uranyl Remediation

Abstract

The nano-MOF+ technique was employed by assembling nanoporous metal-organic framework (MOF) UiO-66 with nanoscale zero-valent iron (ZVI) particles to remove uranyl ions from aqueous solution under anoxic condition for the first time. The synthesized composite of Fe0@UiO-66-COOH exhibits a synergic effect between uranyl sorption by MOF host of UiO-66-COOH and chemical reduction by ZVI, reaching much elevated removal capacity and rate in comparison to those of the pristine UiO-66-COOH. The combined complexation and reduction mechanisms are further elucidated by the synchrotron radiation X-ray absorption near-edge structure analysis. This work highlights the bright future of the nano-MOF+ technique in the application of uranium removal, especially for the remediation of the uranium-contaminated subsurface environment.

Regenerable and stable sp2 carbon-conjugated covalent organic frameworks for selective detection and extraction of uranium

“…However, the performance of amorphous POPs is affected by its irregular pores, burying a large fraction of porosity 9 , and hindering fast mass transfer needed for real-time response 10 . Although MOFs have regular pores and good crystallinity 8 , stability under extreme conditions (acid, base, temperature, and radiation) remains a challenge [11][12][13] . High stability is particularly important for the extraction of UO 2 2+ , as the sample matrix is likely to be strongly radioactive and acidic.…”

Metal‐Organic‐Framework Based Functional Materials for Uranium Recovery: Performance Optimization and Structure/Functionality‐Activity Relationships

“…Wang et al reported a nZVI@UiO-66-COOH composite with nZVI assembled in the pores of UiO-66-COOH. [37] Compared with UiO-66-COOH, Fe 0 @UiO-66-COOH showed much faster adsorption kinetics with nearly 100 % removal of uranium in the first 10 min (Figure 8b). Furthermore, the uptake capacity of the composite for uranium was up to 504 mg/g, 7-fold that of UiO-66-COOH (Figure 8c).…”

“…Wang et al. reported a nZVI@UiO‐66‐COOH composite with nZVI assembled in the pores of UiO‐66‐COOH [37] . Compared with UiO‐66‐COOH, Fe 0 @UiO‐66‐COOH showed much faster adsorption kinetics with nearly 100 % removal of uranium in the first 10 min (Figure 8b).…”

“…The composites of MOFs with other functional materials, such as graphene oxide (GO), [35,69] Fe 3 O 4 , [70] graphitic carbon nitride (g-C 3 N 4 ), [36] nanoscale zero-valent iron (nZVI) [37,71] and carbon sponge (CS), [72] are also promising materials with enhanced uranium uptake performance. The GO-COOH/UiO-66 composite was fabricated by coordination between the Zr(IV) of UiO-66 and the À COOH of GO.…”

“…(d) Potential sequestration mechanism of uranium by Fe 0 @UiO-66-COOH under anaerobic condition. [37] Reprinted with permission from ref. [37].…”