Experimental and theoretical investigations on Se(<scp>iv</scp>) and Se(<scp>vi</scp>) adsorption to UiO-66-based metal–organic frameworks

Wei, Jingmiao; Zhang, Wei; Pan, Weiyi; Li, Chaoran; Sun, Weiling

doi:10.1039/c8en00180d

Cited by 83 publications

(39 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Lewis acid–base complexation (i.e., chemisorption) between the Zr 4+ CUS and the sulfonate headgroup of PFOS was ruled out via the FTIR spectra of the MOFs after adsorption (Figure S3b). No significant changes to the peak heights in the region corresponding to the Zr cluster were observed, consistent with the observations of Sini et al This indicates that no inner-sphere complexation between Zr and PFOS has occurred during the adsorption process …”

Section: Resultsmentioning

confidence: 99%

“…No significant changes to the peak heights in the region corresponding to the Zr cluster were observed, consistent with the observations of Sini et al 32 This indicates that no inner-sphere complexation between Zr and PFOS has occurred during the adsorption process. 61 UiO-66-10 showed significantly greater adsorption capacity than UiO-66-25 despite having similar surface area and pore structure. Given that PFOS was likely completely ionized during the adsorption experiments (pK a = −3.27), 50 a contributing factor to the difference in adsorption behavior between UiO-66-10 and UiO-66-25 could be the electrostatic repulsion resulting from increased amounts of Cl − in the nodes and at linker defect sites.…”

Section: ■ Materials and Methodsmentioning

confidence: 94%

See 1 more Smart Citation

Highly Defective UiO-66 Materials for the Adsorptive Removal of Perfluorooctanesulfonate

Clark

Heck

Powell

et al. 2019

ACS Sustainable Chem. Eng.

159

View full text Add to dashboard Cite

Perfluorooctanesulfonate (PFOS) is a persistent organic pollutant that is bioaccumulative and toxic. While its use in most countries has been restricted to certain industrial applications due to environmental and health concerns, chrome plating and semiconductor manufacturing facilities are industrial point sources of PFOS-containing wastewater. Current remediation technologies are ineffective at treating these highly concentrated industrial effluents. In this work, UiO-66 metal–organic frameworks (MOFs) of several defect concentrations were studied as sorbents for the removal of PFOS from concentrated aqueous solutions. PFOS sorption isotherms indicated that defective UiO-66, prepared with HCl as a modulator, had a maximum Langmuir sorption capacity of 1.24 mmol/g, which was ∼2× greater than powdered activated carbon (PAC), but ∼2× less than that of a commercial ion-exchange resin. Defective UiO-66 adsorbed PFOS 2 orders of magnitude faster than the ion-exchange resin. Large pore defects (∼16 and ∼20 Å) within the framework were critical to the increased adsorption capacity due to higher internal surface area and an increased number of coordinatively unsaturated Zr sites to bind the PFOS head groups. Of the common co-contaminants in chrome plating wastewaters, chloride ions have a negligible effect on PFOS sorption, while sulfate and hexavalent chromium anions compete for cationically charged adsorption sites. These materials were also effective adsorbents for the shorter-chain homologue, perfluorobutanesulfonate (PFBS). The enhanced PFOS and PFBS adsorptive properties of UiO-66 highlight the advantage of structurally defective MOFs as a water treatment approach toward environmental sustainability.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 94%

Highly Defective UiO-66 Materials for the Adsorptive Removal of Perfluorooctanesulfonate

Clark

Heck

Powell

et al. 2019

ACS Sustainable Chem. Eng.

159

View full text Add to dashboard Cite

show abstract

“…This indicates that Zr/Hf and Cu in MOF-818-(Zr, Hf) act as Lewis acid sites, accepting epoxide electron pairs, leading to an increase in the surrounding electron cloud density, thereby shifting the binding energy toward a low direction. [46,47] Compared with fresh MOF-818-(Zr, Hf) catalyst, the surface metal content (see Supporting Information Table S2) and binding energy of MOF-818-(Zr, Hf) catalyst washed with acetone did not change significantly. The XPS characterization of MOF-818-(Zr, Hf) before and after the reaction further proved that MOF-818-(Zr, Hf) is stable in the cycloaddition reaction of CO 2 Table 2.…”

Section: Cycloaddition Of Co 2 and Styrene Oxide Under Different Conditionsmentioning

confidence: 99%

Study of the Cycloaddition of CO₂ with Styrene Oxide Over Six‐Connected spn Topology MOFs (Zr, Hf) at Room Temperature

Jin

Qin

Dong

et al. 2021

Chemistry A European J

View full text Add to dashboard Cite

A series of MOFs with a 6-connected spn topology were synthesized Hf), Hf), Hf)). Through the in situ DRIFTS of NH 3 adsorptiondesorption, we found that the activated catalyst mainly contains Lewis acid sites. The effects of different organic ligands on the Lewis acid of the Zr 6 cluster were analyzed by XPS and NH 3 -TPD, and the relative Lewis acidity of the same metal was obtained: PCN-777 > MOF-808 > MOF-818. In the Py-FTIR results, we confirmed that MOF-818 has a higher acid site density. In the activity test, MOFs with mesoporous structure showed better catalytic activity under normal temperature and pressure. Among them, MOF-818 can still maintain a high degree of crystallinity after catalysis. Finally, we use density functional theory to propose the mechanism of the cycloaddition reaction of carbon dioxide and styrene oxide. The results show that the metal is coordinated with styrene oxide and halogens attack the β carbon of the epoxide.

show abstract

“…We note that the pH conditions will also affect the UiO-66 surface based on previous studies of UiO-66 p K a s and isoelectric point. The first p K a of the μ3-OH group has been identified to be in the region of 3–3.5, − and the isoelectric point of the UiO-66 node is between 4 and 6. ,,− This would suggest that at neutral pH some but not all of the μ3-OH groups on the MOF might be deprotonated. Hence, our neutral UiO-66 cluster model is still a good representation of UiO-66 under different pH conditions.…”

Section: Resultsmentioning

confidence: 99%

Computational Insights into As(V) Removal from Water by the UiO-66 Metal–Organic Framework

2021

View full text Add to dashboard Cite

Metal–organic frameworks (MOFs) such as UiO-66 have shown great promise for the removal of toxic As(V) species from water, but the precise adsorption mechanism is not yet well understood. In this study, we use density functional theory calculations and cluster models to determine accurate energetics and geometries for the adsorption of As(V) species present under varying pH conditions, namely, arsenic acid and related oxyanions. As a result of this analysis, we identify a new adsorption mode in which two As(V) molecules adsorb in a monodentate fashion on two neighboring Zr open metal sites resulting from capping ligand displacement. This mode is preferred over other adsorption modes previously proposed in the literature at acidic and neutral pH. Multidentate adsorption modes involving adsorption of a single As(V) molecule onto both neighboring Zr sites become more competitive as the pH increases, consistent with the lower adsorption performance observed at basic pH. Additionally, we study the influence of the ligands capping the Zr sites on As(V) adsorption thermodynamics. We show that the hydroxide–water ligand pair is the capping ligand most easily displaced by adsorbing As(V) species, suggesting that defects present in the aqueous environment are the ideal site for As(V) species adsorption. Furthermore, we find that adsorption of phosphate oxyanions can thermodynamically compete with As(V) adsorption, thus potentially explaining the observed decreased As(V) adsorption performance in the presence of phosphates. The molecular-level insights gained in this study are used to draw general design principles for the development of new MOFs that can be employed to remove toxic oxyanions from water.

show abstract

Experimental and theoretical investigations on Se(iv) and Se(vi) adsorption to UiO-66-based metal–organic frameworks

Abstract: HSeO3−/SeO32− bonds to UiO-66 on Zr mainly through Lewis acid/base complexation and H2SeO3 bonds on Zr–O–C mainly through hydrogen bonding.

Cited by 83 publications

References 71 publications

Highly Defective UiO-66 Materials for the Adsorptive Removal of Perfluorooctanesulfonate

Highly Defective UiO-66 Materials for the Adsorptive Removal of Perfluorooctanesulfonate

Study of the Cycloaddition of CO₂ with Styrene Oxide Over Six‐Connected spn Topology MOFs (Zr, Hf) at Room Temperature

Computational Insights into As(V) Removal from Water by the UiO-66 Metal–Organic Framework

Contact Info

Product

Resources

About

Experimental and theoretical investigations on Se(iv) and Se(vi) adsorption to UiO-66-based metal–organic frameworks

Abstract: HSeO3−/SeO32− bonds to UiO-66 on Zr mainly through Lewis acid/base complexation and H2SeO3 bonds on Zr–O–C mainly through hydrogen bonding.

Cited by 83 publications

References 71 publications

Highly Defective UiO-66 Materials for the Adsorptive Removal of Perfluorooctanesulfonate

Highly Defective UiO-66 Materials for the Adsorptive Removal of Perfluorooctanesulfonate

Study of the Cycloaddition of CO2 with Styrene Oxide Over Six‐Connected spn Topology MOFs (Zr, Hf) at Room Temperature

Computational Insights into As(V) Removal from Water by the UiO-66 Metal–Organic Framework

Contact Info

Product

Resources

About

Study of the Cycloaddition of CO₂ with Styrene Oxide Over Six‐Connected spn Topology MOFs (Zr, Hf) at Room Temperature