Browsing by Author "Gupta, Raju Kumar"

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    Editorial overview: From linear to circular economies: The importance and application of recycling and reuse
    (Elsevier, 2018-09-19) Gupta, Raju Kumar; Thakur, Vijay Kumar; Matharu, Avtar Singh
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    Graphite modified sodium alginate hydrogel composite for efficient removal of malachite green dye
    (Elsevier, 2020-01-16) Verma, Ankit; Thakur, Sourbh; Mamba, Gcina; Prateek; Gupta, Raju Kumar; Thakur, Pankaj; Thakur, Vijay Kumar
    Herein, porous sodium alginate/graphite based hybrid hydrogel was fabricated as an effective adsorbent for organic pollutant. Sodium alginate was modified through graft polymerization of acrylic acid and subsequently loaded with graphite powder to enhance its adsorption capability. The synthesized sodium alginate cross-linked acrylic acid/graphite (NaA-cl-AAc/GP) hydrogel composite was utilized in the removal of malachite green (MG) dye from aqueous solution using batch adsorption experiments. The NaA-cl-AAc/GP hydrogel composite was characterized by infrared spectroscopy, Raman spectroscopy, thermo-gravimetric analysis, scanning electron microscopy, x-ray photoelectron spectroscopy and x-ray diffraction. Under optimized experimental conditions, a maximum adsorption capacity of 628.93 mg g−1 was attained for malachite green dye. Moreover, the adsorption process could be well described by the Langmuir isotherm model and pseudo-second-order kinetic model. The hydrogel composite also showed 91% adsorption after three consecutive cycles of dye adsorption-desorption. Therefore, the NaA-cl-AAc/GP hydrogel composite is a potentially favourable material towards dye pollution remediation owing to its better swelling rate, environment friendliness, high adsorption potential and regeneration capability.
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    Hydrothermally tailored three-dimensional Ni-V layered double hydroxide nanosheets as high-performance hybrid supercapacitor applications
    (Amercian Chemical Society, 2019-02-14) Tyagi, Ankit; Joshi, Manish Chandra; Shah, Asmita; Thakur, Vijay Kumar; Gupta, Raju Kumar
    Here, we report a facile and easily scalable hydrothermal synthetic strategy to synthesize Ni–V layered double hydroxide applications. NiV LDH nanosheets with varying Ni-to-V ratios were prepared. Three-dimensional curved nanosheets of Ni0.80V0.20 LDH showed better electrochemical performance compared to other synthesized NiV LDHs. The electrode coated with Ni0.80V0.20 LDH nanosheets in a three-electrode cell configuration showed excellent pseudocapacitive behavior, having a high specific capacity of 711 C g–1 (1581 F g–1) at a current density of 1 A g–1 in 2 M KOH. The material showed an excellent rate capability and retained the high specific capacity of 549 C g–1 (1220 F g–1) at a current density of 10 A g–1 and low internal resistances. Owing to its superior performance, Ni0.80V0.20 LDH nanosheets were used as positive electrode and commercial activated carbon was used as negative electrode for constructing a hybrid supercapacitor (HSC) device, having a working voltage of 1.5 V. The HSC device exhibited a high specific capacitance of 98 F g–1 at a current density of 1 A g–1. The HSC device showed a higher energy density of 30.6 Wh kg–1 at a power density of 0.78 kW kg–1 and maintained a high value of 24 Wh kg–1 when the power density was increased to 11.1 kW kg–1. The performance of NiV LDHs nanosheets indicates their great potential as low-cost electrode material for future energy-storage devices
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    Surface modification of cellulose using silane coupling agent
    (Elsevier, 2014-05-26) Thakur, Manju Kumari; Gupta, Raju Kumar; Thakur, Vijay Kumar
    Recently there has been a growing interest in substituting traditional synthetic polymers with natural polymers for different applications. However, natural polymers such as cellulose suffer from few drawbacks. To become viable potential alternatives of synthetic polymers, cellulosic polymers must have comparable physico-chemical properties to that of synthetic polymers. So in the present work, cellulose polymer has been modified by a series of mercerization and silane functionalization to optimize the reaction conditions. Structural, thermal and morphological characterization of the cellulose has been done using FTIR, TGA and SEM, techniques. Surface modified cellulose polymers were further subjected to evaluation of their properties like swelling and chemical resistance behavior