Successful Decontamination of ⁹⁹TcO₄⁻ in Groundwater at Legacy Nuclear Sites by a Cationic Metal‐Organic Framework with Hydrophobic Pockets

Abstract

99 Tc contamination at legacy nuclear sites is aserious and unsolved environmental issue.The selective remediation of 99 TcO 4 À in the presence of al arge excess of NO 3 À and SO 4 2À

99TcO4− removal from legacy defense nuclear waste by an alkaline-stable 2D cationic metal organic framework

“…3e , the removal percentages remain higher than 97% for the molar ratios of NO 3 − to ReO 4 − ranging from 1:1 to 20:1 and K d values higher than 7.96 × 10 3 mL/g can still be achieved (Supplementary Table 6 ). Even at a ratio of 100:1, >88% of ReO 4 − ions could be sequestered, comparable to that of SCU-102 45 . Impressively, when SO 4 2− is present in 6000 fold excess, SCU-103 can still retain high relative amounts of ReO 4 − removal (82%, Fig.…”

“…Moreover, high positive charge density and hydrophobicity also increase the affinity of the 2D layers for 99 TcO 4 − anions. Note that SCU-103 exhibits very high anion-exchange efficiency in contrast to typical commercial resins (A532E and A530E) 16 , 18 and other anion exchangers designed for the removal of anionic contaminants including NDTB-1 13 , 14 , SLUG-21 39 , UiO-66-NH 3 + 48 , comparable to those of SCU-100 16 , SCU-101 42 , and SCU-102 45 . The ultrafast sorption kinetics has great application significance and unique advantages as the short contact time between sorbents and radioactive waste solution would effectively reduce the risk of nuclear leakage and lower the damage of sorbents induced by radiation and hydrolysis.…”

“…3c , the sorption isotherm curves plotted by the equilibrium concentration against the ion-exchange capacity q (mg/g) are fit well with the Langmuir model and the maximum anion-exchange capacity ( q m ) was calculated to be 318 ± 8 mg/g (Supplementary Tables 3 and 4 ). This greatly exceeds the capacity of Yb 3 O(OH) 6 Cl (48.6 mg/g) 49 , NDTB-1 (49.4 mg/g) 49 , UiO-66-NH 3 + (159 mg/g) 48 , NU-1000 (210 mg/g) 47 , SCP-IHEP-1 (211 mg/g) 46 , SCU-101 (247 mg/g) 42 , and SCU-102 (291 mg/g) 45 , but is lower than those of SCU-CPN-1 (999 mg/g) 21 , SCU-100 (541 mg/g) 16 , SLUG-21 (602 mg/g) 39 , PAF-1-F (420 mg/g) 59 .…”

Rapid Room-Temperature Preparation of Hierarchically Porous Metal–Organic Frameworks for Efficient Uranium Removal from Aqueous Solutions

“…Therefore, the development of effective methods for adsorption and removal of uranium from radioactive wastewater is of great significance. Over the past decades, available approaches such as chemical precipitation [ 4 ], solvent extraction [ 5 ], ion exchange [ 6 ], coagulation [ 7 ], and adsorption [ 8 , 9 ] have been developed to extract and remove uranium. Among them, adsorption is considered an effective method for the removal of uranium due to its simple operation process, high efficiency, and low cost, especially for use with low concentrations [ 10 , 11 ].…”

Sb-doped zirconium dioxide submicron fibers for separation of pertechnetate (TcO4–) from aqueous solutions

“…[4,5] However, performances of ion exchange resins and adsorbents often suffer from the presence of other ions, and organic resins are prone to radiation damage. [6] For that reason, several inorganic materials have been developed for more selective removal of TcO 4 and ReO 4 such as mesoporous alumina, [7] metalorganic frameworks, [8,9,10,11] zero valent iron (ZVI), [12,13] Fe 2 O 3 and Fe 3 O 4 [12] and zirconium dioxide nanoparticles anchored onto reduced graphene oxide (ZrO 2 @rGO). [14] In addition, universal nonselective sorbent materials including activated carbon have been utilized in TcO 4 removal.…”