Anion-exchanged and quaternary ammonium functionalized MIL-101-Cr metal-organic framework (MOF) for ReO4−/TcO4− sequestration from groundwater

Abstract

There are few effective technologies for the sequestration of highly water-soluble pertechnetate (TcO 4 − ) from contaminated water despite the urgency of environmental and public health concerns. In this work, anion exchanged and cetyltrimethylammonium bromide (CTAB) functionalized MIL-101-Cr-NO 3 were investigated for perrhenate (ReO 4 − ), a surrogate of TcO 4 − , sequestration from artificial groundwater. Cl − , I − , and CF 3 SO 3 − exchanged MIL-101-Cr proved more effective at ReO 4 − removal than the parent MIL-101-Cr-F. Compared to the parent framework, CTAB functionalized MIL-101-Cr-NO 3 increased ReO 4removal capacity from 39 to 2 139 mg/g, improved the reaction kinetics from ~30 to < 10 minutes to reach full adsorption capacity and the selectivity for ReO 4 − over competing NO 3 − , CO 3 2− , SO 4 2− , and Cl − . Spectroscopic data indicated that the chemical speciation of Re in the exchanged MIL-101-Cr remained ReO 4 − , indicating synergistic sequestration through both anion exchange and non-ion exchange binding with the positively charged ligand of CTAB. These studies foreshadow potential applications of MOFs for the remediation of 99 TcO 4 − from contaminated environments.

Stepwise Assembly of a Multicomponent Heterometallic Metal–Organic Framework via Th6-Based Metalloligands

“…As shown in Figure c, a batch kinetic experiment shows that removal of ReO 4 – by IHEP-11 follows the pseudo-first-order model (Figure S15 and Table S3) and achieves 73% removal at 3 min and up 95% after 10 min. The fast kinetics of ReO 4 – exchange by IHEP-11 is comparable to those of other MOFs reported in the literature. ,− As shown in Figure d, the calculated maximum sorption capacity of IHEP-11 for ReO 4 – at pH 4 is 206 mg g –1 based on the Langmuir model (Figure S16 and Table S4), which can be compared with that of SCU-101 (217 mg g –1 ) and is higher than those for LDH (130 mg – g –1 ) and UiO-66-NH 3 + (159 mg of g –1 ) . IHEP-11 still selectively removes ReO 4 – in the presence of 10 equiv of competing anions including CO 3 2– , ClO 4 – , and NO 3 – (Figure S17).…”

“…The reversible N 2 adsorption–desorption isotherm (Figure S13) indicates that the measured Brunauer–Emmett–Teller surface area of IHEP-11 is 124 m 2 g –1 . ReO 4 – is often used as a nonradioactive alternative to simulate the anion-exchange behavior of radioactive TcO 4 – because they have almost the same charge densities and spatial structures. − Currently, polyoxometalates, cationic MOFs, cationic covalent–organic frameworks, and Ti 2 CT x /poly­(diallyldimethylammonium chloride) nanocomposite are widely studied and applied to the removal of ReO 4 – .…”

Heterometallic Actinide‐Containing Photoresponsive Metal‐Organic Frameworks: Dynamic and Static Tuning of Electronic Properties

“…Exploring optical, catalytic,a nd electronic properties of actinide-containing metal-organic frameworks (An-MOFs) is paramount to addressing the growing challenge of radioactive waste accumulation. [1][2][3][4][5][6][7][8][9][10] However,u nlocking the full potential of An-MOFs for future applications requires acquiring extensive fundamental knowledge relative to their behavior, which is an imperative first step,and thus,isthe primary focus of the presented studies. [11][12][13][14][15][16][17][18][19][20][21][22] Hierarchical hybrids,s uch as metal-organic frameworks (MOFs), allow for performing studies of material properties in astepwise manner by varying one parameter at atime (Scheme 1a).…”

“…Exploring optical, catalytic, and electronic properties of actinide‐containing metal‐organic frameworks (An‐MOFs) is paramount to addressing the growing challenge of radioactive waste accumulation [1–10] . However, unlocking the full potential of An‐MOFs for future applications requires acquiring extensive fundamental knowledge relative to their behavior, which is an imperative first step, and thus, is the primary focus of the presented studies [11–22] .…”

Three coordination polymers built by quaternary-ammonium-modified isophthalic acid

“…Porous coordination polymers (PCPs) or metal-organic frameworks (MOFs) are a new class of porous solids consisting of metal-based nodes (single ions or clusters) bridged by organic linking groups that have attracted much recent attention in many fields, such as carbon capture (Ding et al, 2019), molecular separation (Lin et al, 2019) and heterogeneous catalysis (Hosono & Kitagawa, 2018). Introducing QACs into PCPs would combine the functionalities and porosity of QACs and PCPs, and afford materials which would be promising in many applications, such as the removal/ sequestration of toxic contamination [Hg II (Liu & Du, 2011), ReO 4 À /TcO 4 À (Li et al, 2020) and metal cyanide complexes (Zhang et al, 2018)], heterogeneous catalysis (Wang et al, 2016) and antimicrobials (Han et al, 2020). ISSN 2053ISSN -2296 The method of post-synthetic modification is usually used to build QAC-based PCPs, that is, to build a PCP first and then to introduce a QAC into the PCP network via certain binding forces, such as covalent bonding or hydrogen bonding (Ma et al, 2015;Hahm et al, 2015).…”