Iodine in Metal–Organic Frameworks at High Pressure

Lobanov, Sergey S.; Daly, John A.; Goncharov, Alexander F.; Chan, Xiaojun; Ghose, Sanjit; Zhong, Hui; Ehm, Lars; Kim, Tae Jin; Parise, John B.

doi:10.1021/acs.jpca.8b05443

Cited by 32 publications

(36 citation statements)

References 67 publications

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“…Occurrence, Applications Most research on the adsorption of halogens by metal-organic frameworks has focused on I2, which is motivated by the capture of volatile radioisotopes of I2 from nuclear waste streams. [213][214][215][216][217][218][219][220] Here, we focus on the more volatile lighter halogens Cl2 and Br2, which are much less commonly explored even though the capture and reversible storage of the highly toxic halogen elemental gases is of great interest to improve personal protective equipment, as well as to more safely handle, store, and transport X2.…”

Section: Halogensmentioning

confidence: 99%

Kinetic stability of metal–organic frameworks for corrosive and coordinating gas capture

2019

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Metal-organic frameworks (MOFs) have demonstrated their utility for a variety of applications involving the storage, separation, and sensing of weakly interacting gases of high purity. Exposure to more realistic, impure gas streams and interactions with corrosive and coordinating gases raises the question of chemical robustness, which remains a paramount concern for practical applications of MOFs. However, factors that determine the stability of MOFs remain incompletely understood. Although past researchers attempted to categorize framework materials as either thermodynamically stable or kinetically stable, recent work has elucidated an energetic penalty for porosity for all materials in this class with respect to a dense material. The metastability of porous phases has important implications for the design of materials for gas storage, heterogeneous catalysts, and electronic materials. Here, we focus on two main strategies for stabilization of the porous phase, either by using inert metal ions, or by increasing the heterolytic metal-ligand bond strength, both of which increase the activation barrier for framework collapse. These two strategies have led to exceptionally robust materials for the capture of coordinating and corrosive gases such as water vapor, ammonia, H2S, SO2, NOx, and even elemental halogens, and we review the progress in designing stable materials for these gases. Looking forward, we envision that the continued pursuit of strategies for kinetic stabilization in the synthesis of new MOFs will provide increasing numbers of robust frameworks suited to harsh conditions, and that short-term stability towards these challenging gases will be predictive of long-term stability for applications in less demanding environments.

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Section: Halogensmentioning

confidence: 99%

Kinetic stability of metal–organic frameworks for corrosive and coordinating gas capture

2019

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“…The decrease of the PXRD peak intensity is probably due to the I 2 molecules being incommensurate with the periodicity of the framework, and is also often observedi no ther guest@MOF systems. [13] As showni nF igure2,a tr oom temperature, I 2 is relatively quickly adsorbed and the uptake capacity reaches 34 wt %( 340 mg g À1 MOF )a fter 200 hours. The adsorption rate is then decreased, and by 1000 hours,t he total adsorptioni s 46 wt %( 460 mg g À1 MOF ).…”

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confidence: 92%

Incarceration of Iodine in a Pyrene‐Based Metal–Organic Framework

Gładysiak

Nguyen

Spodaryk

et al. 2018

Chemistry A European J

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Ap yrene-based metal-organic framework (MOF) SION-8 captured iodine (I 2 )v apor with ac apacity of 460 and 250 mg g À1 MOF at room temperature and 75 8C, respectively.S ingle-crystal X-ray diffraction analysisa nd van-der-Waals-correctedd ensity functional theory calculations confirmed the presence of I 2 molecules within the pores of SION-8 and their interaction with the pyrene-based ligands.T he I 2 -pyrene interactions in the I 2 -loaded SION-8 led to a1 0 4 -fold increase of its electrical conductivity compared to the bare SION-8.U pon adsorption, ! 95 %o fI 2 molecules were incarcerated and could not be washed out, signifying the potentialofSION-8 towardst he permanent capture of radioactiveI 2 at room temperature.Radioactivei sotopes of iodine, mainly 129 Ia nd 131 I, are produced in nuclear-related processes and maya ccidentally be released into the atmosphere, as witnessed in Fukushima and Chernobyl,c onstituting am ajor hazard to humans and the environment. Isotope 131 Ih as ar adioactive decay half-life of about eight days, emits b À and g rays, and concentrates in the thyroid gland of the person exposed to the radioactive source causing thyroidc ancer.T he 129 Ii sotope has am uch longerl ife, with ah alf-lifeo f1 5.7 million years, and poses al ong-term disposalr isk. Capturing radioactive iodine is therefore necessary for safe nuclear wastes torage. [1] Wet scrubbing and the use of solid adsorbentsa re two general methodsf or iodine capture, with the latter being often preferred because it does not require the use of highly corrosive liquids. [1] The benchmark solid adsorbents for radioactive iodinec apture is thes ilver (Ag)-exchanged zeolitic mordenite, with an average I 2 -adsorption capacityo fa pproximately 100-130 mg g À1 mordernite at high temperatures (150-200 8C). [1, 2] In recenty ears, metal-organic frameworks (MOFs), which are crystalline materials formed by linkingm etal ions or metal clusters with multi-topic organic ligands, [3] have emergeda sp romising adsorbents for I 2 captured ue to their high porosity [4] and chemicaltunability. [5] For example, our group has previouslyreportedahigh I 2 vapor uptake by HKUST-1 and ZIF-8,a nd their composites with polymers, reaching 538 mg g À1HKUST-1 at 75 8C.[6] The Nenoff group and the Thallapally group have studied the adsorption of I 2 on HKUST-1a nd SBMOFs, respectively,i nt he presence of humidity. [7] However,t he degradation of these MOFs in water,a nd the leaching of I 2 from the I 2 -loaded MOFs when they are in contact with water and common organic solvents,g ive rise to considerable concerns regarding the potential of theseM OFs for I 2 capture. The I 2 leachingi st hought to be due to the weak interaction between the I 2 molecules with the pore surface of the MOF.Here, we report aM OF named SION-8,w hich is based on the employment of 1,3,6,8-tetrakis(p-benzoic acid)pyrene (H 4 TBAPy)a nd Ca II , [8] that can efficientlyc aptureI 2 vapor at both room temperature and at 75 8C. The strategy for I 2 capture is based on the well-know...

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“…[34][35][36][37][38] Another method of catenation of polyiodide subunits is the application of high pressure. [39][40][41][42] It can force the polyiodide building blocks (e.g. I 2 and I 3…”

Section: Introductionmentioning

confidence: 99%