Zinc oxide nanopillars as an electrocatalyst for direct redox sensing of cadmium

Bhanjana, G.,Dilbaghi, N.,Singhal, N.K.,Kim, K.H.,Kumar, S. THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2017 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.53 No.-

In this paper, we report an ultrasensitive and selective technique for direct electrochemical sensing of cadmium (Cd) by zinc oxide nanopillars (ZONPs) synthesized using a facile chemical method. The synthesized ZONPs have been characterized in terms of their topological, morphological, elemental, structural, and optical properties using various microscopic and spectroscopic techniques. A gold electrode was modified with the as-synthesized ZnO nanostructures and utilized for direct redox sensing of Cd using cyclic voltammetry (CV) and chronoamperometric techniques. This fabricated sensor demonstrated excellent sensitivity and selectivity for direct redox sensing of Cd in real and laboratory samples. Using chronoamperometry, the developed sensor demonstrated ultra-sensitivity (10μAcm<SUP>-2</SUP>ppb<SUP>-1</SUP>) with a detection limit of 4ppb (p-value<0.0001, R-value>0.99) in a linear range of 5-50ppb. The enhanced reproducibility of the sensor in the presence of common interfering ions offers the potential for use in diagnostic applications involving food adulteration and in clinical healthcare.

Robust and direct electrochemical sensing of arsenic using zirconia nanocubes

Bhanjana, Gaurav,Dilbaghi, Neeraj,Chaudhary, Savita,Kim, Ki-Hyun,Kumar, Sandeep Royal Society of Chemistry 2016 The Analyst Vol.141 No.13

<P>The presence of heavy metal ions in the environment and in food items can severely harm human health. Thus, simple, reliable, sensitive, quick, and accurate methods for their detection must be developed as a means to improve healthcare worldwide. To this end, a robust method was developed for the direct sensing of arsenic(III) in control and real environmental samples (at neutral pH) by a gold electrode that was modified with zirconia nanocubes synthesized via a facile hydrothermal route. This sensing system was used to build a sensing profile for arsenic ions after characterization of their elemental, optical, chemical, and morphological behavior. Electrochemical sensing of arsenic was achieved by cyclic voltammetry (CV) and chronoamperometry with an ultra-sensitivity of 550 nA cm(-2) ppb(-1) and a detection limit of 5 ppb (linear range of 5-60 ppb with a response time below 2 s). Although this system experienced small interference from Cd ions, the results of the real sample analysis were comparable to those of other standard techniques. The proposed method is advantageous and can be used to assess the toxicity of water, food, and other environmental samples without requiring any toxic solutions and/or gasses in any of the analytical steps. Moreover, due to its low price, portability, and easy mass production, it can be adopted for use in screen-printed electrodes.</P>

Carbon nanotubes as sorbent material for removal of cadmium

Bhanjana, Gaurav,Dilbaghi, Neeraj,Kim, Ki-Hyun,Kumar, Sandeep Elsevier 2017 Journal of molecular liquids Vol.242 No.-

<P>Heavy metal ions are highly toxic industrial pollutants of which maximum levels are regulated such as in the ppb range for drinking water. Elevated levels of heavy metals in natural water may have a detrimental effect on both human health and the environment. Carbon nanotubes (CNTs) have been investigated widely over last two decades for numerous potential applications to exert considerable technological impact on future miniaturized, compact, cost effective, and efficient devices. The novel tubular structures of CNTs became one of the most valuable materials in water management due to their distinct features such as inertness, porous structure, low density, and affinity for pollutants. Such astonishing features help make them overcome the shortcomings of activated carbon. In this research, we focused on the synthesis, characterization, and evaluation of multi walled carbon nano tubes (MWCNTs) as adsorbent for removal of cadmium. MWCNTs synthesized in size range of 60-70 nm (width) and length in microns using chemical vapour deposition (CVD) method were characterized by the field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Raman spectroscopic analyses. These MWCNTs when explored for the removal of cadmium ions (Cd2+) from their aqueous solutions exhibited a maximum adsorption capacity of 181.8 mg/g with the Langmuir isotherm model (R-2 = 0.98). The findings of this research work project that CNTs can play a vital role as nanoadsorbent towards heavy metals management. (C) 2017 Elsevier B.V. All rights reserved.</P>

Direct ultrasensitive redox sensing of mercury using a nanogold platform

Bhanjana, G.,Dilbaghi, N.,Bhalla, V.,Kim, K.H.,Kumar, S. Elsevier 2017 Journal of molecular liquids Vol.225 No.-

<P>Rapid industrialization and innovative material processing routes have resulted in the contamination of natural resources. Qualitative and quantitative estimation of mercury in food, beverages, water sources, and other environmental media has become of prime importance for human well-being. The present healthcare sector desires cheap, easy to use, and portable field-based monitoring kits for the detection of hazardous pollutants like mercury. In view of these facts, there is a strong need for robust, cost effective, reproducible, ultrasensitive, selective, and portable technology for the detection of mercury in samples. Here, we report the facile direct redox sensing of mercury ions at the ppb level. In this work, a combined application of linear sweep voltammetry (LSV) and chronoamperometry techniques was made for the direct electrochemical sensing of mercury ions on a nanogold platform. This is the first report in which the direct electrochemical sensing of mercury is demonstrated based on LSV & chronoamperometry techniques without the use of any biomolecule/co-coordinating ligand. ISV works in one direction/sweep, thereby diminishing the possible occurrence of interfering agents in a reverse sweep. This new approach is more reliable, robust, ultrasensitive, and user friendly relative to previous methods. The fabricated Au/Nafion/GC electrode showed ultra-high sensitivity of 11.75 A cm(-2) ppb(-1) [detection limit of 3.78 ppb (19 nM) with a linearity ranging up to 50 ppm] at a response time of <2 s, demonstrating wide applicability and efficacy of this technique for sensing mercury. (C) 2016 Published by Elsevier B.V.</P>

Low temperature synthesis of copper oxide nanoflowers for lead removal using sonochemical route

Bhanjana, Gaurav,Dilbaghi, Neeraj,Kim, Ki-Hyun,Kumar, Sandeep Elsevier 2017 Journal of molecular liquids Vol.244 No.-

<P>In this research, copper oxide (CuO) nanoflowers were obtained using a low-temperature synthesis technique with a high yield rate, and were tested as an adsorbent for the removal of lead ions (Pb2+) in aqueous systems. These CuO nanoflowers were initially characterized according to their topological, morphological, chemical, elemental, and structural parameters. Their morphology and size were investigated by field emission scanning electron microscopy (FESEM). It was found that the synthesized CuO nanoflowers ranged in size range from 20 to 90 nm with consistent features in a monoclinic phase, as elucidated by X-ray powder diffraction (XRD) analysis. Fourier transform infrared (FTIR) and energy-dispersive X-ray spectroscopy (EDS) analyses confirmed their composition to be pure CuO with minimal impurities. When these nanoflowers were utilized as an adsorbent for the removal of Pb2+, they yielded a maximum adsorption capacity of 188.7 mg/g at an adsorbent dose of 0.5 mg/mL with R-2 = similar to 0.98. The adsorption capacity of our CuO nanoflowers was considerably higher than that of adsorbents,explored by other researchers. Therefore, these CuO nanoflowers are proposed as an efficient sorbent material for waste water treatment. (C) 2017 Elsevier B.V. All rights reserved.</P>

Zinc oxide nanopillars as an electrocatalyst for direct redox sensing of cadmium

Gaurav Bhanjana,Neeraj Dilbaghi,Nitin Kumar Singhal,김기현,Sandeep Kumar 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.53 No.-

In this paper, we report an ultrasensitive and selective technique for direct electrochemical sensing of cadmium (Cd) by zinc oxide nanopillars (ZONPs) synthesized using a facile chemical method. The synthesized ZONPs have been characterized in terms of their topological, morphological, elemental, structural, and optical properties using various microscopic and spectroscopic techniques. A gold electrode was modified with the as-synthesized ZnO nanostructures and utilized for direct redox sensing of Cd using cyclic voltammetry (CV) and chronoamperometric techniques. This fabricated sensor demonstrated excellent sensitivity and selectivity for direct redox sensing of Cd in real and laboratory samples. Using chronoamperometry, the developed sensor demonstrated ultra-sensitivity (10 mA cm2 ppb1) with a detection limit of 4 ppb (p-value < 0.0001, R-value > 0.99) in a linear range of 5–50 ppb. The enhanced reproducibility of the sensor in the presence of common interfering ions offers the potential for use in diagnostic applications involving food adulteration and in clinical healthcare.

Carbon nanotubes: a novel material for multifaceted applications in human healthcare

Kumar, Sandeep,Rani, Ruma,Dilbaghi, Neeraj,Tankeshwar, K.,Kim, Ki-Hyun The Royal Society of Chemistry 2017 Chemical Society reviews Vol.46 No.1

<P>Remarkable advances have been achieved in modern material technology, especially in device fabrication, and these have facilitated the use of diverse materials in various applications. Carbon nanotubes (CNTs) are being successfully implemented in drug delivery, sensing, water purification, composite materials, and bone scaffolds. Thus, CNTs must meet a wide range of criteria such as surface modification, high aspect ratio, desired conductivity, high porosity and loading, non-toxicity, specificity, and selectivity, and compatibility for device fabrication. The main focus of this review is to explore the maximum applications of CNTs for human health, and we particularly focus on nanocarrier and biomedical applications. The scope of this review initially covers the basic aspects of CNTs and is also extended further to describe their synthesis strategies as well as various challenges encountered in their functionalization, dispersion, and toxicity. Our discussion also emphasizes future directions for these emerging fields of research.</P>

Novel electrochemical sensing of arsenic ions using a simple graphite pencil electrode modified with tin oxide nanoneedles

Bhanjana, Gaurav,Mehta, Navjot,Chaudhary, Ganga Ram,Dilbaghi, Neeraj,Kim, Ki-Hyun,Kumar, Sandeep Elsevier 2018 Journal of molecular liquids Vol.264 No.-

<P><B>Abstract</B></P> <P>Electrochemical sensors have attained enormous attention in last few years. Various contaminants like pesticides, explosives, pharmaceutical drugs, and biological fluids have been determined qualitatively as well as quantitatively with the assistance of cyclic voltammetry (CV), linear sweep voltammetry (LSV), amperometry, and impedance-based techniques. Nanoengineering based modified electrodes have contributed to the establishment of the on-site detection platform for various harmful analytes with the aid of electrochemical method. In this research, CV-based detection method has been developed and validated against arsenic (As<SUP>3+</SUP>) in real as well as laboratory samples. Lead pencil (<I>cost around 0.015 USD</I>) has been utilized as working electrode after modification with tin oxide (SnO<SUB>2</SUB>) nanoneedles. SnO<SUB>2</SUB> nanoneedles (size: 60–80 nm), synthesized using chemical precipitation method, were characterized for their elemental, topological, morphological and structural features. The surface of lead pencil (containing graphite/carbon (C)) was then coated with these nanoneedles with the help of nafion (as binding agent). This fabricated sensor recorded a detection limit of 10 ppb (linear range: 50–500 ppb) with ultrasensitivity of 28.13 μA cm<SUP>−2</SUP> ppb<SUP>−1</SUP>. This method was then applied to the direct ion quantitation of arsenic in real environmental and industrial samples collected from diverse locations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Low temperature synthesis of SnO<SUB>2</SUB> nanoneedles </LI> <LI> In-depth characterization using TEM, SEM, FTIR and XRD analyses </LI> <LI> Fabrication of SnO<SUB>2</SUB>/Nafion/C pencil electrode </LI> <LI> Detection of As<SUP>3+</SUP> in real waste-water samples using fabricated electrode </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Recent advances and remaining challenges for polymeric nanocomposites in healthcare applications

Kumar, Sandeep,Sarita, Sandeep,Nehra, Monika,Dilbaghi, Neeraj,Tankeshwar, K.,Kim, Ki-Hyun Elsevier 2018 Progress in polymer science Vol.80 No.-

<P><B>Abstract</B></P> <P>Remarkable advancements in material technologies have accelerated the use of many new materials and their hybrids and composites in diverse applications. Among such available options, polymer nanocomposites are recognized to have the potential to bring future revolution, especially because of their flexible functionalities and related advantages (e.g., good strength, large surface area to volume ratio, large flame retardancy, high elastic modulus, enhanced density, and thermo-mechanical/optoelectronic/magnetic properties). These nanocomposites have been successfully incorporated into diverse fields of applications such as drug delivery, tissue engineering, gene therapy, food preservation, biosensing, and bioimaging. Thus, the primary focus of this review is placed to give an integrated overview of polymer nanocomposites along with their synthesis routes, surface treatment strategies, and applications in the healthcare sector (e.g., drug delivery, 3D bio-implant, bioimaging, food processing, and other miscellaneous biomedical applications). Our discussion also highlights future directions for this emerging field of research.</P>

Carbon nanotubes: A potential material for energy conversion and storage

Kumar, Sandeep,Nehra, Monika,Kedia, Deepak,Dilbaghi, Neeraj,Tankeshwar, K,Kim, Ki-Hyun Elsevier 2018 Progress in energy and combustion science Vol.64 No.-

<P><B>Abstract</B></P> <P>Carbon nanotube-based materials are gaining considerable attention as novel materials for renewable energy conversion and storage. The novel optoelectronic properties of CNTs (e.g., exceptionally high surface area, thermal conductivity, electron mobility, and mechanical strength) can be advantageous for applications toward energy conversion and storage. Although many nanomaterials are well known for the unique structure-property relations, such relations have been sought most intensively from CNTs due to their extreme diversity and richness in structures. For the development of energy-related devices (like photovoltaic cells, supercapacitors, and lithium ion batteries), it is critical to conduct pre-evaluation of their design, operation, and performance in terms of cost, life time, performance, and environmental impact. This critical review was organized to address the recent developments in the use of CNT-based materials as working/counter electrodes and electrolytes in photovoltaic devices and as building blocks in next-generation flexible energy storage devices. The most promising research in the applications of CNTs toward energy conversion and storage is highlighted based on both computational and experimental studies along with the challenges for developing breakthrough products.</P>