Insights into the adsorption capacity and breakthrough properties of a synthetic zeolite against a mixture of various sulfur species at low ppb levels

Vellingiri, K.,Kim, K.H.,Kwon, E.E.,Deep, A.,Jo, S.H.,Szulejko, J.E. Academic Press 2016 Journal of environmental management Vol.166 No.-

<P>The sorptive removal properties of a synthetic A4 zeolite were evaluated against sulfur dioxide (SO2) and four reference reduced sulfur compounds (RSC: hydrogen sulfide (H2S), methanethiol (CH3SH), dimethyl sulfide (DMS, (CH3)(2)S), and dimethyl disulfide (DMDS, CH3SSCH3). To this end, a sorbent bed of untreated (as-received) A4 zeolite was loaded with gaseous standards at four concentration levels (10-100 partper-billion (ppb (v/v)) at four different volumes (0.1, 0.2, 0.5, and 1 L increments) in both increasing (IO: 0.1-1.0 L) and decreasing volume order (DO: 1.0 to 0.1 L). Morphological properties were characterized by PXRD, FTIR, and BET analysis. The removal efficiency of SO2 decreased from 100% for all concentrations at 0.1 L (initial sample volume) to similar to 82% (100 ppb) or similar to 96% (10 ppb) at 3.6 L In contrast, removal efficiency of RSC was near 100% at small loading volumes but then fell sharply, irrespective of concentration (10-100 ppb) (e.g., 32% (DMS) to 52% (H2S) at 100 ppb). The adsorption capacity of zeolite, if expressed in terms of solid-gas partition coefficient (e.g., similar to the Henry's law constant (mmol kg(-1) Pa-1)), showed moderate variabilities with the standard concentration levels and S compound types such as the minimum of 2.03 for CH3SH (at 20 ppb) to the maximum of 13.9 for SO2 (at 10 ppb). It clearly demonstrated a notable distinction in the removal efficiency of A4 zeolite among the different S species in a mixture with enhanced removal efficiency of SO2 compared to the RSCs. (c) 2015 Elsevier Ltd. All rights reserved.</P>

Probing Out-of-Plane Charge Transport in Black Phosphorus with Graphene-Contacted Vertical Field-Effect Transistors

Kang, Junmo,Jariwala, Deep,Ryder, Christopher R.,Wells, Spencer A.,Choi, Yongsuk,Hwang, Euyheon,Cho, Jeong Ho,Marks, Tobin J.,Hersam, Mark C. American Chemical Society 2016 Nano letters Vol.16 No.4

<P>Black phosphorus (BP) has recently emerged as a promising narrow band gap layered semiconductor with optoelectronic properties that bridge the gap between semimetallic graphene and wide band gap transition metal dichalcogenides such as MoS2. To date, BP field-effect transistors have utilized a lateral geometry with in-plane transport dominating device characteristics. In contrast, we present here a vertical field-effect transistor geometry based on a graphene/BP van der Waals heterostructure. The resulting device characteristics include high on-state current densities (>1600 A/cm(2)) and current on/off ratios exceeding 800 at low temperature. Two distinct charge transport mechanisms are identified, which are dominant for different regimes of temperature and gate voltage. In particular, the Schottky barrier between graphene and BP determines charge transport at high temperatures and positive gate voltages, whereas tunneling dominates at low temperatures and negative gate voltages. These results elucidate out-of-plane electronic transport in BP and thus have implications for the design and operation of BP-based van der Waals heterostructures.</P>

A facile chemical route for recovery of high quality zinc oxide nanoparticles from spent alkaline batteries

Deep, A.,Sharma, A.L.,Mohanta, G.C.,Kumar, P.,Kim, K.H. Pergamon Press ; Elsevier Science Ltd 2016 Waste management Vol.51 No.-

Recycling of spent domestic batteries has gained a great environmental significance. In the present research, we propose a new and simple technique for the recovery of high-purity zinc oxide nanoparticles from the electrode waste of spent alkaline Zn-MnO<SUB>2</SUB> batteries. The electrode material was collected by the manual dismantling and mixed with 5M HCl for reaction with a phosphine oxide reagent Cyanex 923® at 250<SUP>o</SUP>C for 30min. The desired ZnO nanoparticles were restored from the Zn-Cyanex 923 complex through an ethanolic precipitation step. The recovered particle product with about 5nm diameter exhibited fluorescent properties (emission peak at 400nm) when excited by UV radiation (excitation energy of 300nm). Thus, the proposed technique offered a simple and efficient route for recovering high purity ZnO nanoparticles from spent alkaline batteries.

The sensitive detection of formaldehyde in aqueous media using zirconium-based metal organic frameworks

Vellingiri, K.,Deep, A.,Kim, K.H.,Boukhvalov, D.W.,Kumar, P.,Yao, Q. Elsevier Sequoia 2017 Sensors and actuators. B, Chemical Vol.241 No.-

<P>The amino derivative of the UiO-66 metal organic framework (MOF) was investigated for potential use as a sensing probe for formaldehyde (FA) in an aqueous medium. The sensitivity and specificity of this MOF probe were virtually unaffected by the presence of other tested reference aldehydes, e.g., propionaldehyde( PA), butyraldehyde (BA), and valeraldehyde (VA). The maximum incubation time for the interaction of the MOF probe against 100 ppm of FA standard was estimated at 2 min. The linear detection of FA molecules using the proposed probe was performed in the range of 10-100 ppm with a limit of detection (LOD) at 4 ppm. The stability of the MOF for FA detection was estimated through a series of adsorption-desorption cycles. DFT calculations showed that the selective sensing/capture of FA corresponded to the formation of a stable, non-covalent bond between FA and the C6H3NH2 unit of the MOF. This interaction decreased the HOMO/LUMO gap of FA by approximately 0.8 eV, a trend that was not evident for all other aldehydes. The results of FTIR, TGA, and XPS analysis confirmed a small but visible change in the chemical environment of the N-H and C-H bonds of UiO-66-NH2 upon their interactions with FA molecules. Therefore, the proposed MOF probe appears suitable for sensing FA in an aqueous medium. (C) 2016 Elsevier B.V. All rights reserved.</P>

Application of MoS₂ modified screen-printed electrodes for highly sensitive detection of bovine serum albumin

Kukkar, M.,Sharma, A.,Kumar, P.,Kim, K.H.,Deep, A. Elsevier Pub. Co 2016 Analytica chimica acta Vol.939 No.-

The present work reports the application of a new molybdenum disulphide (MoS<SUB>2</SUB>)-based electrochemical platform for highly sensitive quantitation of an iron-binding protein, bovine serum albumin (BSA). The gold screen-printed electrodes were modified with MoS<SUB>2</SUB> nanoflakes, followed by bioconjugation with anti-BSA antibodies. Using the above bioelectrode, cyclic voltammetric analysis was carried out in the presence of a Fe<SUP>3+</SUP>/Fe<SUP>2+</SUP> redox probe which exhibited a linear response of peak current with varying concentrations of BSA up to 10 ng/mL (with a detection limit of 0.006 ng/mL). This study is novel in that it shows a considerable enhancement of signal during electrochemical sensing of a protein.

Recent advances in the photovoltaic applications of coordination polymers and metal organic frameworks

Kaur, Rajnish,Kim, Ki-Hyun,Paul, A. K.,Deep, Akash The Royal Society of Chemistry 2016 Journal of Materials Chemistry A Vol.4 No.11

<▼1><P>Coordination polymers and metal organic frameworks (CPs/MOFs) have attracted a great deal of attention in a variety of scientific fields due to their unique and intriguing structural properties.</P></▼1><▼2><P>Coordination polymers and metal organic frameworks (CPs/MOFs) have attracted a great deal of attention in a variety of scientific fields due to their unique and intriguing structural properties. Photovoltaic applications of these porous polymers belong to a relatively new area of research. The current status of research on this subject amply highlights the usefulness of CPs/MOFs in improving the properties of next-generation photovoltaic devices (<I>e.g.</I>, dye-sensitized solar cells). This review article was written to cover the recent advancements that have been achieved in this rapidly expanding area of research. It also compares and contrasts the energy conversion efficiencies in photovoltaic applications using different MOFs and other systems.</P></▼2>

Graphene quantum dot modified screen printed immunosensor for the determination of parathion

Mehta, J.,Bhardwaj, N.,Bhardwaj, S.K.,Tuteja, S.K.,Vinayak, P.,Paul, A.K.,Kim, K.H.,Deep, A. Academic Press 2017 Analytical biochemistry Vol.523 No.-

<P>The widespread use of pesticides has immense effect on increased crop productions. However, they are also responsible for posing detrimental health hazards and/or for contaminating the environment with chemical residues. A routine and an on-field detection of pesticide residues in different food, water, and soil samples has become a need of the hour for which biosensors can offer a viable alternative. The present work reports a functionalized graphene quantum dot (GQD) based screen printed electro-chemical immunosensor for the detection of parathion. The application of GQDs has permitted the realization of a sensitive, robust, and reproducible sensor unlike those carried out earlier for the similar purposes. This immunosensor exhibited a dynamic linear response for parathion within the range of 0.01 -10(6) ng/L with a very low detection limit of 46 pg/L. According to the analysis of potential interferences, the proposed sensor was specifically detecting parathion even in the presence of its metabolite, paraoxon. The investigations of the proposed sensing approach with respect to stability, response reproducibility, and regeneration have fully supported its potential practical applicability. (C) 2017 Elsevier Inc. All rights reserved.</P>

A critical review on the diverse preconcentration procedures on bag samples in the quantitation of volatile organic compounds from cigarette smoke and other combustion samples

Kim, K.H.,Szulejko, J.E.,Kwon, E.,Deep, A. Elsevier Scientific Pub. Co 2016 Trends in analytical chemistry Vol.85 No.3

<P>It is challenging to analyze environmental tobacco smoking (ETS) samples given the diversity of hazardous toxic components and the difficulty of collecting/treating the samples. As one of the simple means to quantify volatile organic compounds (VOCs) in ETS samples, researchers have used such combinations as the bag sampling method and in-bag solid-phase microextraction for GC-MS analysis. In this review, we describe various factors involved in the application of paired sampling/preconcentration procedures for the analysis of VOCs, especially in ETS samples (and other combustion sources). The reliability of such paired procedures is also evaluated by considering several components, e.g., the factors controlling QA/QC, the associated sources of bias, and the effect of temporal stability (on bag sampling). Accordingly, it is recommended that several QA-related terms involved in such application (e.g., accuracy, robustness, high throughput, and quantitativeness) ought to be assessed properly and reported in a more objective manner. (C) 2016 Elsevier B.V. All rights reserved.</P>

Metal organic frameworks for sensing applications

Kumar, P.,Deep, A.,Kim, K.H. Elsevier Scientific Pub. Co 2015 Trends in analytical chemistry Vol.73 No.-

A metal organic framework (MOF) represents a new class of hybrid material built from metal ions with well-defined coordination geometry and organic bridging ligands. Over the past few years, MOFs have attracted a great deal of attention due to their intriguing framework architecture, topology, and optical properties. MOFs have provided promising perspectives in various research fields, such as catalysis, energy storage, drug-delivery systems, non-linear optics, and gas storage. Recently, the application of MOFs was further extended to cover new, interesting fields of sensing toward various target components, including small molecules, solvents, pesticides, explosives, and biological markers. In this review, we focus on recent progress achieved in MOF research with respect to general sensing principles and analytical performance. This review also discusses future industrial applications in sensing that are of immense research interest.

Genetic Algorithm: A Tutorial Review

Deep Malya Mukhopadhyay,Maricel O. Balitanas,Alisherov Farkhod A,Seung-Hwan Jeon,Debnath Bhattacharyya 보안공학연구지원센터(IJGDC) 2009 International Journal of Grid and Distributed Comp Vol.2 No.3