Acoustic Properties of Metal-Organic Frameworks

Water covers about 70% of the Earth’s surface, but the amount of freshwater available for human use is only 2.5% and, although it is continuously replenished via the water cycle, freshwater is a finite and limited resource. The Earth’s water is affected by pollution and while water quality is an issue of global concern, the specific regulations on contaminants of emerging concern (CECs) are limited. In order to achieve the goals set by EU regulations, the treatment of wastewater is a scientifically and technologically challenging issue. Metal–organic frameworks (MOFs) are promising materials used for the removal of priority and emerging contaminants from wastewater, since they can mitigate those contaminants via both adsorption as well as catalysis processes. MOFs can offer selective adsorption of CECs by various adsorption mechanisms. The catalytic removal of priority and emerging organic contaminants from wastewater using MOFs implies Fenton, electro-Fenton, and photo-Fenton processes. Overall, MOFs can be considered as promising materials for the elimination of priority and emerging organic contaminants from various wastewater types, but the involved processes must be studied in detail for a larger number of compounds.

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“…In general, crystal shape of a MOF is related to its internal structure (see Figure 1 B for MOF-5 [ 45 ], UiO-66, and ZIF-8) [ 44 ].…”

Section: Types Of Environmentally Relevant Mofsmentioning

confidence: 99%

“…[ 13 ] 2021, Elsevier ( A ). The crystal structure diagrams for MOF-5 (I), UiO-66 (II), and ZIF-8 (III) [ 44 ] ( B ).…”

Section: Figurementioning

confidence: 99%

Recent Progress in the Removal of Legacy and Emerging Organic Contaminants from Wastewater Using Metal–Organic Frameworks: An Overview on Adsorption and Catalysis Processes

Badea

Niculescu

2022

Materials

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“…There are other works on piezoelectricity in MOFs where electromechanical (EM) response was measured using piezoelectric force microscopy (PFM). − Whereas they are worthy to be mentioned, it must be noted that several nonpiezoelectric effects can induce additional contributions to PFM response, thus leading to misinterpretation. Several issues due to the calibration of the microscope and challenges in excluding the contribution of electrostatic and other forces have been discussed in the literature, thus indicating that piezoelectric constants with high precision cannot be measured from PFM in most cases. − Recently, also the theoretical prediction of the piezoelectric tensor for three MOFs whose d ik values range between 2 and 23 pC/N has been reported …”

Section: Introductionmentioning

confidence: 99%

“…22−24 Recently, also the theoretical prediction of the piezoelectric tensor for three MOFs whose d ik values range between 2 and 23 pC/N has been reported. 25 Another factor that is considered important in piezoelectric energy harvesting applications is the dielectric constant of the material, as noted from the figure of merit (FOM)…”

Section: Introductionmentioning

confidence: 99%

Structure–Property Relationship of Piezoelectric Properties in Zeolitic Imidazolate Frameworks: A Computational Study

Mula

Donà

Civalleri

et al. 2022

ACS Appl. Mater. Interfaces

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Metal−organic frameworks (MOFs) are a class of nanoporous crystalline materials with very high structural tunability. They possess a very low dielectric permittivity ε r due to their porosity and hence are favorable for piezoelectric energy harvesting. Even though they have huge potential as piezoelectric materials, a detailed analysis and structure−property relationship of the piezoelectric properties in MOFs are lacking so far. This work focuses on a class of cubic non-centrosymmetric MOFs, namely, zeolitic imidazolate frameworks (ZIFs) to rationalize how the variation of different building blocks of the structure, that is, metal node and linker substituents affect the piezoelectric constants. The piezoelectric tensor for the ZIFs is computed from ab initio theoretical methods. From the calculations, we analyze the different contributions to the final piezoelectric constant d 14 , namely, the clamped ion (e 14 0 ) and the internal strain (e 14 int ) contributions and the mechanical properties. For the studied ZIFs, even though e 14 (e 14 0 + e 14 int ) is similar for all ZIFs, the resultant piezoelectric coefficient d 14 calculated from piezoelectric constant e 14 and elastic compliance constant s 44 varies significantly among the different structures. It is the largest for CdIF-1 (Cd 2+ and −CH 3 linker substituent). This is mainly due to the higher elasticity or flexibility of the framework. Interestingly, the magnitude of d 14 for CdIF-1 is higher than II−VI inorganic piezoelectrics and of a similar magnitude as the quintessential piezoelectric polymer polyvinylidene fluoride.

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“…Crystalline metal–organic frameworks (MOFs) appeared to be promising solids for application as gas sorbents, separators, and new active elements in opto- and micro-electronic devices. − The highly ordered porous structure of MOFs provides an efficient and lossless propagation of mechanical, thermal, and electromagnetic energy, as well as molecules and charged particles along the structure, which underlies the operation of the above devices. Meanwhile, the transformation of the parent crystal structure into various amorphous and liquid phases − allows for designing new MOF-based materials for which a long-range order plays a minor role.…”

mentioning

confidence: 99%

Insights into Solid-To-Solid Transformation of MOF Amorphous Phases

et al. 2022

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Metal–organic frameworks (MOFs) have been recently explored as crystalline solids for conversion into amorphous phases demonstrating non-specific mechanical, catalytic, and optical properties. The real-time control of such structural transformations and their outcomes still remain a challenge. Here, we use in situ high-resolution transmission electron microscopy with 0.01 s time resolution to explore non-thermal (electron induced) amorphization of a MOF single crystal, followed by transformation into an amorphous nanomaterial. By comparing a series of M-BTC (M: Fe3+, Co3+, Co2+, Ni2+, and Cu2+; BTC: 1,3,5-benzentricarboxylic acid), we demonstrate that the topology of a metal cluster of the parent MOFs determines the rate of formation and the chemistry of the resulting phases containing an intact ligand and metal or metal oxide nanoparticles. Confocal Raman and photoluminescence spectroscopies further confirm the integrity of the BTC ligand and coordination bond breaking, while high-resolution imaging with chemical and structural analysis over time allows for tracking the dynamics of solid-to-solid transformations. The revealed relationship between the initial and resulting structures and the stability of the obtained phase and its photoluminescence over time contribute to the design of new amorphous MOF-based optical nanomaterials.

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Acoustic Properties of Metal-Organic Frameworks

Cited by 14 publications

References 54 publications

Recent Progress in the Removal of Legacy and Emerging Organic Contaminants from Wastewater Using Metal–Organic Frameworks: An Overview on Adsorption and Catalysis Processes

Recent Progress in the Removal of Legacy and Emerging Organic Contaminants from Wastewater Using Metal–Organic Frameworks: An Overview on Adsorption and Catalysis Processes

Structure–Property Relationship of Piezoelectric Properties in Zeolitic Imidazolate Frameworks: A Computational Study

Insights into Solid-To-Solid Transformation of MOF Amorphous Phases

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