Luminescent metal-organic frameworks for the detection of nitrobenzene in aqueous media

Vellingiri, Kowsalya,Boukhvalov, Danil W.,Pandey, Sudhir Kumar,Deep, Akash,Kim, Ki-Hyun Elsevier 2017 Sensors and actuators. B Chemical Vol.245 No.-

<P><B>Abstract</B></P> <P>The feasibility of highly water stable Zr-based metal organic frameworks (MOFs: UiO-66-NH<SUB>2</SUB>) as a sensing probe material was explored for the detection of the electron deficient nitrobenzene (NB) molecule in an aqueous phase. The probe system was highly sensitive toward the NB molecule within the range of 10–100ppm with a linear range of 0–30ppm and a quenching efficiency of around 95% (at 100ppm). The limit of detection (LOD) of the proposed probe was estimated to be 0.9ppm. In contrast, this method was not affected sensitively by potential interferences such as other aromatic compounds. For instance, benzene (B), toluene (T), and chlorobenzene (CB) showed reduced quenching efficiencies (<40%). The specificity toward NB molecules for the proposed probe was appreciable in the presence of co-existing components (B, T, and CB). DFT calculations showed that the sensing mechanism was ascribable to electron transfer from the excited missed-linker induced sites of the ZrOH to the NB molecule. This interaction was confirmed by an FTIR analysis of the UiO-66-NH<SUB>2</SUB>-NB material. Therefore, the proposed UiO-66-NH<SUB>2</SUB> probe can be used as a potent sensing material for the NB even at low concentrations in an aqueous medium.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Quenching mechanism of the metal-organic frameworks (MOFs) is good for sensing hazardous compounds. </LI> <LI> The environmental significance of nitro aromatic compounds is well known due to their health impacts. </LI> <LI> The sensing efficiency of a Zr-based MOFs (UiO-66-NH<SUB>2</SUB>) is assessed against the detection of nitrobenzene. </LI> <LI> The performance of UiO-66-NH<SUB>2</SUB> was demonstrated along with the temporal stability and regenerability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Towards high-efficiency sorptive capture of radionuclides in solution and gas

Vellingiri, Kowsalya,Kim, Ki-Hyun,Pournara, Anastasia,Deep, Akash Elsevier 2018 Progress in materials science Vol.94 No.-

<P><B>Abstract</B></P> <P>As globalization and rapid population growth have raised global energy needs, the demand for nuclear energy has increased drastically. To make use of such energy more reliably, the efficient disposal of nuclear wastes has become a major challenge. With this in mind, numerous research efforts have been put to safely store, capture, and immobilize radioactive waste. As a result, a variety of sorbent materials with different physical, chemical, and structural properties have been invented or discovered. The maximum removal capacity of these sorbents were then assessed for a variety of radionuclides in soluble and/or gaseous forms. The pre-/post-synthetic modification of these sorbent materials has also been investigated intensively to help enhance their overall stability, tunability, and capacity without altering or damaging the main framework. In this review, we explored the performance of different materials for the sorption of most important radionuclide species including uranium, cobalt, europium, iodine, cesium, strontium, technetium, krypton, xenon, and argon. To begin with, we classified sorbent materials into three categories in light of their structural evolvement over time. We also described the critical factors to consider for the proper application of these categorized sorbents (e.g., sorption properties, structural characteristics, reversibility, and renewability). Finally, we discussed briefly the present limitations and future prospects of these technologies.</P>

Ambient particulate matter in a central urban area of Seoul, Korea

Vellingiri, Kowsalya,Kim, Ki-Hyun,Ma, Chang-Jin,Kang, Chang-Hee,Lee, Jin-Hong,Kim, Ik-Soo,Brown, Richard J.C. Elsevier 2015 CHEMOSPHERE - Vol.119 No.-

<P><B>Abstract</B></P> <P>The concentrations of PM<SUB>2.5</SUB> and PM<SUB>10</SUB> were monitored at a central urban area of Yongsan (YS), Seoul, Korea during 2013. The daily average concentrations of both PM<SUB>2.5</SUB> and PM<SUB>10</SUB> fractions, were 26.6±12.6 and 45.0±20.4μgm<SUP>−3</SUP>, respectively. The observed PM<SUB>2.5</SUB> concentration slightly exceeded the annual standard value (25μgm<SUP>−3</SUP>) set by the Korean Ministry of Environment (KMOE), while that of PM<SUB>10</SUB> was slightly lower than its guideline value (50μgm<SUP>−3</SUP>). Comparison of the monthly mean values (μgm<SUP>−3</SUP>) of both PM fractions showed maximum concentrations in January (PM<SUB>2.5</SUB>: 36.9 and PM<SUB>10</SUB>: 59.7) and minimum concentrations in September (PM<SUB>10</SUB>: 28.1) and October (PM<SUB>2.5</SUB>: 14.9). The existence of strong correlations between the concentrations of PM and some gaseous pollutants (e.g., CO, SO<SUB>2</SUB>, and NOx) indicated the commonality of contributing source processes, such as traffic and industrial emissions. The results of a back-trajectory (BT) analysis also suggests that the PM pollution in the study area is likely to have been affected by many sources such as Asian dust, volcanic emissions, and industrial activities in the surrounding countries (China, Russia, and Japan).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sources of ambient particulate matter are diverse enough to deteriorate air quality in urban areas. </LI> <LI> A study has been undertaken to account for the factors governing particle pollution in an urban area. </LI> <LI> Different transport routes of air masses into the area were assessed to differentiate the sources for PM. </LI> <LI> It suggests potent roles of many sources, e.g., Asian dust, volcanic emissions, and industrial activities. </LI> </UL> </P>

The utilization of zinc recovered from alkaline battery waste as metal precursor in the synthesis of metal-organic framework

Vellingiri, Kowsalya,Tsang, Daniel C.W.,Kim, Ki-Hyun,Deep, Akash,Dutta, Tanushree,Boukhvalov, Danil W. Elsevier 2018 Journal of Cleaner Production Vol.199 No.-

<P><B>Abstract</B></P> <P>In the treatment of spent wastes, seeking extra economic incentives (e.g., through their regeneration into value-added end products) along with environmental protection is a highly ideal option to consider. In this context, a process was developed to utilize spent alkaline battery waste as a source medium of zinc (Zn<SUP>2+</SUP>) ions for the synthesis of a high-value material, metal organic frameworks (MOFs). For this purpose, multiple options including acid leaching and base precipitation were first compared for separation of Zn<SUP>2+</SUP> ions from battery waste. Secondly, MOF-5 synthesis was carried out through two different routes: one using the Zn<SUP>2+</SUP> ions separated from waste batteries (W-MOF-5) and the other using pure chemicals (P-MOF-5). Finally, differences in the structural properties (e.g., crystallinity and morphology) between the two MOF-5 types were assessed through characterization experiments (e.g., FTIR, PXRD, and SEM analyses) and modeling (DFT) studies. W-MOF-5 was found to possess tetragonal lattice parameters which indicated decrease in the Zn<SUP>2+</SUP> ions in the framework. This deficiency increased the interplanar Bragg angles which led to the different size and shape of W-MOF-5. Also, the PXRD spectrum indicated the presence of all peaks at similar position with that of P-MOF-5. Additionally, the preparation of 1 kg of W-MOF-5 requires a low cost (42 USD) when one considers >90% of solvent recovery. Also in terms of materials cost, the synthesis of W-MOF-5 was highly cost-effective than that of ZnO nanoparticles. In light of many compatibilities between MOFs synthesized through the two different routes, the method proposed in this work can be further developed toward a simple, fast, and reliable route for MOF-5 production from battery waste.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Metal–organic frameworks as media for the catalytic degradation of chemical warfare agents

Vellingiri, Kowsalya,Philip, Ligy,Kim, Ki-Hyun Elsevier Publishing Company 2017 Coordination chemistry reviews Vol.353 No.-

<P><B>Abstract</B></P> <P>Because of the highly toxic properties of chemical warfare agents (CWA), an effective technology for the deactivation/detoxification of CWAs is desperately needed. Due to the safety issues involved in treating CWAs, catalytic conversion into (an)other non-toxic or less toxic material is suggested as one of the most favorable routes for their treatment. In this respect, many materials including zeolites, activated carbon, and metal oxides have been used as catalysts for the hydrolysis/methanolysis of the highly toxic organophosphate bonds of CWAs. However, the limited structural flexibility of these catalytic materials has been a hurdle to expanding detoxification on a large scale. A new option of using various porous materials for this application, including metal–organic frameworks (MOFs), has provided the potential for structural tailoring of the deactivation of CWAs. To discuss the potential of MOFs as deactivation/detoxification platforms for CWAs, we have initially described the structural pre-requisites for improving the catalytic activity of the MOF catalysts. A detailed explanation of the MOF catalysis and suitable examples are provided along with future perspectives and recommendations for such applications. We hope that this review will help provide a new roadmap for the scientists who are working in the area of heterogeneous catalytic approaches for the efficient degradation of CWAs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Degradation of chemical warfare agents (CWA) is an important socioenvironmental concern. </LI> <LI> MOFs have been studied for the degradation of various CWAs due to their functional moieties. </LI> <LI> Such capacity was expanded further through functionalization viz coordinating/conjugating agents. </LI> <LI> Here the potential use of MOFs as the key media for the CWA degradation is described. </LI> </UL> </P>

Metal–organic framework composites as electrocatalysts for electrochemical sensing applications

Kempahanumakkagari, Sureshkumar,Vellingiri, Kowsalya,Deep, Akash,Kwon, Eilhann E.,Bolan, Nanthi,Kim, Ki-Hyun Elsevier 2018 Coordination chemistry reviews Vol.357 No.-

<P><B>Abstract</B></P> <P>Metal–organic frameworks (MOFs) are porous coordination polymers linked by metal ions and ligands. With the progress of MOF research, many redox active MOFs have been synthesized by judicious selection of the electroactive metal ions and/or organic functional groups. Due to the unique properties (e.g., high surface areas, tailorable pore sizes, and exposed active sites), MOFs are found to have a wide range of redox activities to be applied in various fields (e.g., microporous conductors, electrocatalysts, energy storage devices, and electrochemical sensors). The potential of the MOFs composites has also been realized as ideal hosts for functional materials (like conducting nanoparticles). These composites are thus demonstrated to have superior electrocatalytic/electrochemical sensing properties than their pristine forms. Accordingly, various MOF composite-based platforms have been developed as efficient electrochemical sensors for environmental and biochemical targets. This review was organized to provide up-to-date information and insights into the fundamental aspects of MOF composites as electrocatalytic/electrochemical sensors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MOF composites have been developed with superior electrocatalytic properties. </LI> <LI> MOF composites can be applied as electrocatalysts for electrochemical sensing. </LI> <LI> They were employed for sensing environmental analytes like metals and organics. </LI> <LI> Their use was extended further to detect various biological targets like glucose. </LI> </UL> </P>

Recent advances in controlled modification of the size and morphology of metal-organic frameworks

Liu, Botao,Vellingiri, Kowsalya,Jo, Sang-Hee,Kumar, Pawan,Ok, Yong Sik,Kim, Ki-Hyun Springer-Verlag 2018 Nano research Vol.11 No.9

Activation strategies of metal-organic frameworks for the sorption of reduced sulfur compounds

Deng, Yaxin,Vellingiri, Kowsalya,Kim, Ki-Hyun,Boukhvalov, Danil W.,Philip, Ligy Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.350 No.-

<P><B>Abstract</B></P> <P>In order to investigate the possible options to improve the pore properties of metal-organic frameworks (MOFs), the sorptive capacity of MOF-199 was assessed based on the two contrasting activation approaches (i.e., ‘chemical (<B>C</B>)’ and ‘thermal (<B>T</B>)’ activation) against four reduced sulfur (S) compounds <B>(</B>RSCs: H<SUB>2</SUB>S, CH<SUB>3</SUB>SH, (CH<SUB>3</SUB>)<SUB>2</SUB>S (DMS), and CH<SUB>3</SUB>SSCH<SUB>3</SUB> (DMDS)). In order to represent the pristine (<B>C1</B>) and chemically activated forms of MOF-199 (<B>C2</B>), the pores were filled by N,N′-dimethylformamide (DMF) (i.e., as synthesized) and dichloromethane (CH<SUB>2</SUB>Cl<SUB>2</SUB>), respectively. For comparative purpose, these samples were further subject to thermal treatment (150 °C under 100 mL min<SUP>−1</SUP>) and named as <B>T1</B> and <B>T2</B>, respectively. The combined effects of chemical/thermal activation were found to be most effective to enhance the sorption capacity of MOF-199. (Note that such advantage was not evident when treated by chemical activation only.) Overall, the relative ordering of sorption capacities between four different types of MOF-199, when tested against diverse S compounds, was found to be DMDS > CH<SUB>3</SUB>SH > H<SUB>2</SUB>S > DMS. The mechanism for such sorption patterns was ascribed to two major competing interactions: a) S-Cu for lighter S and b) –CH<SUB>3</SUB> group (in S compound) and aromatic ring (in MOF ligand) for heavier S. This synergetic effect was also confirmed by both theoretically (density functional theory (DFT)) and experimentally (Fourier Transform Infrared (FTIR) spectroscopy analysis). As such, MOF-199 prepared through both chemical and thermal treatments was identified as an efficient sorbent to capture S compounds even in ambient conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> It is a delicate goal to develop an efficient tool to control reduced sulfur compounds (RSCs). </LI> <LI> The feasibility of chemical/solvent and thermal activation of MOF-199 was tested against RSCs. </LI> <LI> The sorption properties of MOF-199 were then explored against their mixtures. </LI> <LI> The sorption capacities of activated MOF-199 were compared in terms of breakthrough volume. </LI> <LI> The processes controlling the sorption of RSCs to MOFs were analyzed from various respects. </LI> </UL> </P>

Recent progress in biological and chemical sensing by luminescent metal-organic frameworks

Kukkar, Deepak,Vellingiri, Kowsalya,Kim, Ki-Hyun,Deep, Akash Elsevier 2018 Sensors and actuators. B Chemical Vol.273 No.-

<P><B>Abstract</B></P> <P>Luminescent metal organic frameworks (LMOFs), formed by coordinated bridging between metal ions and multidentate organic ligands with relevant fluorescent structures, have been the subject of intense research due to their tunable photoluminescent properties. The numerous permutations and combinations of available metal ions and organic linkers can yield novel LMOFs for countless applications. The luminescent characteristics of LMOFs depend upon many factors, including their structural components, coordination milieu of the metal ions, chemical structure/volume of the pore surfaces, and host-guest interactions between the LMOFs and reacting species (e.g., non-covalent interactions, coordination bonds, and π-π interactions). The combined effects of these parameters justify the expansion of their application in various fields. In addition, they are recognized as ideal candidates for biological applications due to their high loading capacity of functional molecules, facile surface modification and conjugation with biocompatible ligands (such as antibodies and proteins), tunable structural geometry, and intrinsic biocompatibility. By elaborating on these points, this article provides up-to-date information on the developments in the scientific/technological application of LMOFs, with special emphasis on the types, properties, and potential in sensing and biological applications. The discussion is further expanded to describe the major challenges and constraints of this research field.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A Test of Relative Removal Properties of Various Offensive Odors by Zeolite

Adedeji A. Adelodun,Kowsalya Vellingiri,전병훈,오종민,Sandeep Kumar,김기현 한국대기환경학회 2017 Asian Journal of Atmospheric Environment (AJAE) Vol.11 No.1

The adsorptive removal properties of synthetic A4 zeolite were investigated against a total of 16 offensive odors consisting of reduced sulfur compounds (RSCs), nitrogenous compounds (NCs), volatile fatty acids (VFAs), and phenols/indoles (PnI). Removal of these odors was measured using a laboratory-scale impinger-based adsorption setup containing 25 g of the zeolite bed (flow rate of 100 mL min-1). The high est and lowest breakthrough (%) values were shown for PnIs and RSCs, respectively, and the maximum and minimum adsorption capacity (μg g-1) of the zeolite was observed for the RSCs (range of 0.77-3.4) and PnIs (0.06-0.104), respectively. As a result of sorptive removal by zeolite, a reduction in odor strength, measured as odor intensity (OI), was recorded from the minimum of approximately 0.7 OI units (indole [from 2.4 to 1.6]), skatole [2.2 to 1.4], and p-cresol [5.1 to 4.4]) to the maximum of approximately 4 OI units (methanethiol [11.4 to 7.5], n-valeric acid [10.4 to 6.5], i-butyric acid [7.9 to 4.4], and propionic acid [7.2 to 3.7]). Likewise, when removal was examined in terms of odor activity value (OAV), the extent of reduction was significant (i.e., 1000-fold) in the increasing order of amy acetate, ibutyric acid, phenol, propionic acid, and ammonia.