Simultaneous detection of Lead and Cadmium using a composite of Zeolite Imidazole Framework and Reduced Graphene Oxide (ZIF-67/rGO) via electrochemical approach

Naini Garg,Akash Deep,Amit L Sharma 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.4

Present work reports the application of a composite of ZIF-67/rGO for the simultaneous detection of traces of lead and cadmium via square wave anodic stripping voltammetry (SWASV) technique. For this, graffoil sheets were modified with synthesized composite for the electrode fabrication [(ZIF-67/rGO)/Graffoil] for its use in sensing studies. The SWASV response of (ZIF-67/rGO)/Graffoil electrode was optimized against deposition potential (-1.0 V) and time (350 s), required for the accumulation of metal ions onto the sensor electrode. The performance of the sensing electrode was then evaluated for lead (Pb<SUP>2+</SUP>) and cadmium (Cd<SUP>2+</SUP>) ions at various concentrations. The sensor displayed linear response in a wide concentration range of 5-100 ppb. The peak current of the electrode was found to be shifted towards the higher potential at higher metal ion concentrations. Based on the response measured, the limit of detection (LOD) of the fabricated sensor has been estimated and found to be 5 and 2.93 ppb for Pb<SUP>2+</SUP> and Cd<SUP>2+</SUP> ions, respectively. The results obtained revealed good specificity of the proposed sensor towards Pb<SUP>2+</SUP> and Cd<SUP>2+</SUP> ions in the co-presence of several other ions. In addition, the sensor exhibited good reproducibility with a relative standard deviation (RSD) of ~2% for both Pb<SUP>2+</SUP> and Cd<SUP>2+</SUP> ions.

Nanomaterial-based electrochemical sensors for arsenic - A review

Kempahanumakkagari, Sureshkumar,Deep, Akash,Kim, Ki-Hyun,Kumar Kailasa, Suresh,Yoon, Hye-On Elsevier Applied Science 2017 Biosensors & Bioelectronics Vol. No.

<P><B>Abstract</B></P> <P>The existence of arsenic in the environment poses severe global health threats. Considering its toxicity, the sensing of arsenic is extremely important. Due to the complexity of environmental and biological samples, many of the available detection methods for arsenic have serious limitations on selectivity and sensitivity. To improve sensitivity and selectivity and to circumvent interferences, different electrode systems have been developed based on surface modification with nanomaterials including carbonaceous nanomaterials, metallic nanoparticles (MNPs), metal nanotubes (MNTs), and even enzymes. Despite the progress made in electrochemical sensing of arsenic, some issues still need to be addressed to realize cost effective, portable, and flow-injection type sensor systems. The present review provides an in-depth evaluation of the nanoparticle-modified electrode (NME) based methods for the electrochemical sensing of arsenic. NME based sensing systems are projected to become an important option for monitoring hazardous pollutants in both environmental and biological media.</P> <P><B>Highlights</B></P> <P> <UL> <LI> About 140 million people inadvertently consume groundwater containing high levels of As. </LI> <LI> Sensitive and selective analysis of As is of high importance to identify the contaminated source. </LI> <LI> This review summarizes nanomaterial-modified electrode interfaces for sensing inorganic As. </LI> <LI> The use of nanoparticle-modified electrodes are set to meet the commercial challenges. </LI> <LI> It is desirable to develop cost effective, field portable, and highly selective sensors to monitor As. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Various types of nanoparticles used in electrode modification for electrochemical sensing applications toward arsenic</P> <P>[DISPLAY OMISSION]</P>

An engineering insight into block copolymer self-assembly: Contemporary application from biomedical research to nanotechnology

Samaddar, Pallabi,Deep, Akash,Kim, Ki-Hyun Elsevier 2018 Chemical engineering journal Vol.342 No.-

<P><B>Abstract</B></P> <P>Because of their unique ordered structures, block copolymers (BCPs) are known to form a broad range of morphologies (e.g., cylinders, vesicles, spheres, and lamellae). These types of assemblies can be utilized for various potential and practical applications in numerous fields including nanotechnology. This review addresses classification of different BCPs based on polymeric moieties and arrangement of polymer chains present in their structure. Physicochemical characteristics of BCP micelles in aqueous media are also discussed along with the beneficial features of BCP self assembly in the generation of nanostructures. Potential applications of BCP-drug conjugates have also been described with numerous case studies. In addition, successful implementation of BCP self-assembly in modern age research of nanoporous ultrafiltration membrane, nanolithography, functionalized nanomaterial preparation has been overviewed with mechanistic details. Finally, we offer a brief perspective on the future opportunities of BCPs in diverse research fields.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Block copolymers (BCPs) tend to occur exclusively in nature. </LI> <LI> Through aggregation of different monomers, BCPs exhibit enhanced stability and durability. </LI> <LI> BCPs are here classified by the structure/shape of the dissimilar blocks in the polymer chain. </LI> <LI> Property of BCPs is assessed in terms of micelle-forming capacity, solubility, and functionality. </LI> <LI> Coverage of this review highlight the future prospects of BCPs to benefit their future research. </LI> </UL> </P>

Performance of Air Fresher System for the Removal of Various Odorants Released from Foodstuffs

김기현,Adedeji A. Adelodun,Akash Deep,권일한,전의찬,김용현,조상희,이민희,조성백,황옥화 한국대기환경학회 2017 Asian Journal of Atmospheric Environment (AJAE) Vol.11 No.1

The effectiveness of four air fresher (AF) systems was evaluated with respect to their removal efficiencies against offensive odorants. For this purpose, malodorous species were generated by exposing freshly cooked foods emitting odorants with levels moderately above their respective threshold values in a confined room. The deodorization efficiency of the four AF systems was then tested for a period of 30 min by estimating the extent of reduction in odorant levels after the operation of each AF. The removal efficiency of the four AF units against each odorant was evaluated as follows: (1) between AF products from different manufacturers, (2) between odorants and ultrafine particulate matter (PM2.5), and (3) between operation and natural degassing. The average sorptive removal of odorants was generally <80% and considered less effective or non-effective relative to PM2.5. Further examination of odor reduction, if evaluated in terms of odor indices like odor intensity (OI) and odor activity value (OAV), recorded a mean of 33% and 87%, respectively. The overall results of this study confirmed that all tested AF units were not effective to resolve odor problems created under our testing conditions.

Quantum-sized nanomaterials for solar cell applications

Kumar, Sandeep,Nehra, Monika,Deep, Akash,Kedia, Deepak,Dilbaghi, Neeraj,Kim, Ki-Hyun Elsevier 2017 RENEWABLE & SUSTAINABLE ENERGY REVIEWS Vol.73 No.-

<P><B>Abstract</B></P> <P>To date, the development of clean and sustainable energy sources has been a central focal point of research, supporting the worldwide rising demand for energy along with associated environmental concerns. The abundance of solar energy on the surface of the earth and its popular appeal makes it a promising candidate to comply with long-term energy demands. In this article, we provide a comprehensive review on different generations of solar cell based on the technological and economic aspects. The focus is on nanomaterial-based solar cells such as quantum dot sensitized solar cells (QDSSCs), a new PV mechanism that offers a new pathway for controlling energy flow. Over the past few years, a significant improvement has been achieved in the energy conversion efficiency (ECE) of QDSSCs (e.g., from 1% to beyond 11%). As such, they are a very promising alternative to conventional crystalline and thin film PV technologies due to their low cost, easy fabrication, and high performance. This review highlights the progress of QDSSCs along with future scope of innovative graphene structures, e.g., graphene-semiconductor nanomaterial (G-SNM), graphene-carbon nanotubes (G-CNT), and graphene-metal nanomaterial (G-MNM) hybrids in PV cells. In addition to graphene, we discuss other 2D materials that have remarkable optoelectronic properties for PV devices. The ECE of green QDSSCs (~11.61% certified) is now approaching that of dye-sensitized solar cells (~13%) through the technical advancement of many counterparts (e.g., photo-electrodes, sensitizers, electrolytes, and counter electrodes). Therefore, QDSSCs exhibit sufficient potential for future research focusing on the development of highly efficient solar cells.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</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>

Metal–organic frameworks (MOFs) for the removal of emerging contaminants from aquatic environments

Dhaka, Sarita,Kumar, Rahul,Deep, Akash,Kurade, Mayur B.,Ji, Sang-Woo,Jeon, Byong-Hun Elsevier 2019 Coordination chemistry reviews Vol.380 No.-

<P><B>Abstract</B></P> <P>Metal–organic frameworks (MOFs) have gained attention as promising materials for aqueous-phase sorptive removal of emerging contaminants (ECs). Attributes such as large adsorption capacity, high surface area, tunable porosity, hierarchical structure, and recyclability give MOFs an edge over conventional adsorbents. The poor stability of MOFs in water is a major challenge to their real-world environmental application. The performance of MOFs and their selectivity toward targeted pollutants for removal can be regulated by judicious selection of metal ion and organic linker. A range of water-stable MOFs (e.g., MIL-53, MIL-100, MIL-101, UiO-66, and MIL-125) and their composites with other materials have been reported to remove the ECs from water. The present review critically addressed the performance of MOFs for the adsorptive removal of different categories of ECs from water and the adsorption mechanisms involved. The performance of MOFs compared with other adsorbents has also been discussed. This body of rapidly developing research signifies the emerging importance of MOFs in environmental applications and provides a future direction for the development of treatment technology to effectively remove ECs from aqueous environments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MOFs offer great opportunities in environmental remediation of different pollutants. </LI> <LI> MOFs are potential adsorbents for water purification. </LI> <LI> Strategies to improve the aqueous phase stability of MOFs are reviewed. </LI> <LI> Performance of MOFs in aqueous phase emerging contaminants removal are highlighted. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Recovery of nanomaterials from battery and electronic wastes: A new paradigm of environmental waste management

Dutta, Tanushree,Kim, Ki-Hyun,Deep, Akash,Szulejko, Jan E.,Vellingiri, Kowsalya,Kumar, Sandeep,Kwon, Eilhann E.,Yun, Seong-Taek Elsevier 2018 RENEWABLE & SUSTAINABLE ENERGY REVIEWS Vol.82 No.3

<P><B>Abstract</B></P> <P>Recycling battery and electronic wastes for the recovery of nanomaterials (NMs) has ushered in a new era in nanotechnology and environmental research. Essentially, NM recycling offers a two-way method of environmental remediation. The potential economic benefits of high-value NM end-products are conducive for industrial scale operations. Simultaneously, it reduces the industrial consumption of finite primary resources. The added benefits of abating environmental pollution (e.g., from VOCs, VFAs, SO<SUB>2</SUB>, NOx, and heavy metals) further contributes to the significance of ongoing research in this particular area. However, some challenges still persist due to the lack of motivation for recycling and the problem of the limited usability (or low stability) of many of the end-products. In this study, we aimed to evaluate different basic aspects of waste recycling in relation to NM recovery, along with other associated techniques. The utility of recovered NMs and potential options for NM recovery are described as highlighting features to help construct a future roadmap for this emerging scientific field. In addition, an assessment of the potential economic returns from recycling high-purity NMs is provided. Outcomes of this review may fuel further innovations for optimizing the current recycling methods for the efficient synthesis of commercial-grade, high purity NMs at minimal cost.</P>

Cyclodextrin-metal–organic framework (CD-MOF): From synthesis to applications

T. Rajkumar,Deepak Kukkar,김기현,손종렬,Akash Deep 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-

Porous coordination compounds, commonly known as metal–organic frameworks (MOFs), exhibit manyunique characteristics (e.g., high surface area, high porosity, and tunability). The corresponding naturallyoccurring counterparts, CD-MOFs have opened a new avenue of research in light of its non-toxic, edible,and renewable nature. These characteristics have led to their applications into numerous directionsincluding drug delivery, CO2 capture, separation/purification, adsorption, sensors, food packaging,electrical conductors, memristors, photocatalysis, and polymerization. In this review, we provide a briefdiscussion about the available technologies for the synthesis of CD-MOFs and their applications in manyprospective areas.

A novel CdTe/Eu-MOF photoanode for application in quantum dot-sensitized solar cell to improve power conversion efficiency

Rajnish Kaur,Amit L. Sharma,김기현,Akash Deep 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.53 No.-

The quantum dots (QDs) and metal-organic frameworks (MOFs) have emerged as the efficient nanomaterials for light harvesting, photocatalysis, and photovoltaic applications. Here, the application of a composite of CdTe QDs with a europium-MOF was demonstrated as a novel photoanode to achieve the improvement in the short circuit current density from 19.8 (CdTe QD) to 28.45 mA/cm2 (CdTe QD/Eu- MOF). So does power conversion efficiency (PCE) between the former (1.67%) and the latter (3.02%). This 1.35% of difference (or absolute enhancement) in the PCE can be attributed to an enhanced surface area and increased photon absorption capacity.