Browsing by Author "Padil, Vinod V. T."
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- ItemA Polymeric Composite Material (rGO/PANI) for Acid Blue 129 Adsorption(MDPI, 2020-05-03) Kukulski, Tomasz; Wacławek, Stanisław; Silvestri, Daniele; Krawczyk, Kamil; Padil, Vinod V. T.; Fryczkowski, Ryszard; Janicki, Jarosław; Černík, MiroslavOver the years, polyaniline (PANI) has received enormous attention due to its unique properties. Herein, it was chosen to develop a new polymeric composite material: reduced graphene oxide/polyaniline (rGO/PANI). The composite was prepared by a simple and cost-effective fabrication method of formation by mixing and sonication in various conditions. The obtained materials were characterized and identified using various techniques such as scanning electron microscopy (SEM), Raman and ATR–FTIR spectroscopy, and X-ray diffraction (XRD). The objective of the paper was to confirm its applicability for the removal of contaminants from water. Water could be contaminated by various types of pollutants, e.g., inorganics, heavy metals, and many other industrial compounds, including dyes. We confirmed that the Acid Blue 129 dyes can be substantially removed through adsorption on prepared rGO/PANI. The adsorption kinetic data were modeled using the pseudo-first-order and pseudo-second-order models and the adsorption isotherm model was identified.
- ItemAntimicrobial gum bio-based nanocomposites and their industrial and biomedical applications(ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND, 2019-01-01) Zare, Ehsan Nazarzadeh; Makvandi, Pooyan; Borzacchiello, Assunta; Tay, Franklin R.; Ashtari, Behnaz; Padil, Vinod V. T.Gum polysaccharides are derived from renewable sources. They are readily available, inexpensive, non-hazardous and eco-friendly. Depending upon the source, gums may be categorized as microbial gums, plant exudate gums or seed gums. Naturally occurring gum carbohydrates find multiple applications in the biomedical arena, compared with synthetic compounds, because of their unique structures and functionalities. Gums and their biocomposites are preferred for sustained drug delivery because they are safe and edible as well as more susceptible to biodegradation. The present review provides a state-of-the-art conspectus on the industrial and biomedical applications of antimicrobial gum-based biocomposites. Different kinds of gums polysaccharides will first be addressed based on their sources. Metal-, carbon- and organic-based nanostructures that are used in gum nanocomposites will then be reviewed with respect to their industrial and biomedical applications, to provide a backdrop for future research.
- ItemBioplastic Fibers from Gum Arabic for Greener Food Wrapping Applications(AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA, 2019-03-18) Padil, Vinod V. T.; Senan, Chandra; Waclawek, Stanislaw; Černík, Miroslav; Agarwal, Seema; Varma, Rajender S.The fabrication of bioplastic fibers from gum arabic (GA), a natural tree gum exudate, is described via the electrospinning method. The enrichment in surface properties of this bioplastic fiber was evaluated by methane plasma and gamma-ray irradiation treatments. The fibers with their modified forms, both treated and untreated, were investigated by various characterization techniques such as scanning electron microscopy, atomic force microscopy, X-ay diffraction and attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, BET surface area, water contact angle, and tensile strength measurements. A switchable hydrophobic/hydrophilic functionality on GA bioplastic fibers was established through CH4 plasma and gamma-ray irradiation treatments; higher water contact angle (130 degrees) was observed in GA bioplastic fibers that had undergone methane plasma treatment. However, the untreated and gamma-ray-irradiated GA bioplastics exhibited hydrophilic behavior. The comparative properties such as water resistance, antioxidant potency, gas barrier attributes, antibacterial effectiveness, biodegradability and food contact migration through the GA bioplastic fibers (untreated, plasma treated, and gamma-ray-irradiated) were assessed. The present work, in contrast to other existing bioplastic fibers, has the potential of becoming a viable option in greener food packaging as well as in environmental and medically related products based on tree gums.
- ItemChemical oxidation and reduction of hexachlorocyclohexanes: A review(2019-01-01) Waclawek, Stanislaw; Silvestri, Daniele; Hrabák, Pavel; Padil, Vinod V. T.; Torres-Mendieta, Rafael; Waclawek, Maria; Černík, Miroslav; Dionysiou, Dionysios D.Lindane (gamma-hexachlorocyclohexane) and its isomers (HCH) are some of the most common and most easily detected organochlorine pesticides in the environment. The widespread distribution of lindane is due to its use as an insecticide, accompanied by its persistence and bioaccumulation, whereas HCH were disposed of as waste in unmanaged landfills. Unfortunately, certain HCH (especially the most reactive ones: gamma- and alpha-HCH) are harmful to the central nervous system and to reproductive and endocrine systems, therefore development of suitable remediation methods is needed to remove them from contaminated soil and water. This paper provides a short history of the use of lindane and a description of the properties of HCH, as well as their determination methods. The main focus of the paper, however, is a review of oxidative and reductive treatment methods. Although these methods of HCH remediation are popular, there are no review papers summarising their principles, history, advantages and disadvantages. Furthermore, recent advances in the chemical treatment of HCH are discussed and risks concerning these processes are given.
- ItemFunctionalization of Polymers and Nanomaterials for Biomedical Applications: Antimicrobial Platforms and Drug Carriers(MDPI, 2020-06-23) Delfi, Masoud; Ghomi, Matineh; Zarrabi, Ali; Mohammadinejad, Reza; Baghban, Taraghdari Zahra; Ashrafizadeh, Milad; Nazarzadeh Zare, Ehsan; Agarwal, Tarun; Padil, Vinod V. T.; Mokhtari, Babak; Rossi, Filippo; Perale, Giuseppe; Sillanpaa, Mika; Borzacchiello, Assunta; Maiti, Tapas Kumar; Makvandi, PooyanThe use of polymers and nanomaterials has vastly grown for industrial and biomedical sectors during last years. Before any designation or selection of polymers and their nanocomposites, it is vital to recognize the targeted applications which require these platforms to be modified. Surface functionalization to introduce the desired type and quantity of reactive functional groups to target a cell or tissue in human body is a pivotal approach to improve the physicochemical and biological properties of these materials. Herein, advances in the functionalized polymer and nanomaterials surfaces are highlighted along with their applications in biomedical fields, e.g., antimicrobial therapy and drug delivery.
- ItemMicroscopic Techniques for the Analysis of Micro and Nanostructures of Biopolymers and Their Derivatives(MDPI, 2020-03-01) Venkateshaiah, Abhilash; Padil, Vinod V. T.; Nagalakshmaiah, Malladi; Waclawek, Stanislaw; Černík, Miroslav; Varma, Rajender S.Natural biopolymers, a class of materials extracted from renewable sources, is garnering interest due to growing concerns over environmental safety; biopolymers have the advantage of biocompatibility and biodegradability, an imperative requirement. The synthesis of nanoparticles and nanofibers from biopolymers provides a green platform relative to the conventional methods that use hazardous chemicals. However, it is challenging to characterize these nanoparticles and fibers due to the variation in size, shape, and morphology. In order to evaluate these properties, microscopic techniques such as optical microscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM) are essential. With the advent of new biopolymer systems, it is necessary to obtain insights into the fundamental structures of these systems to determine their structural, physical, and morphological properties, which play a vital role in defining their performance and applications. Microscopic techniques perform a decisive role in revealing intricate details, which assists in the appraisal of microstructure, surface morphology, chemical composition, and interfacial properties. This review highlights the significance of various microscopic techniques incorporating the literature details that help characterize biopolymers and their derivatives.
- ItemProduction of electrospun nanofibers based on graphene oxide/gum Arabic(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2019-03-01) Silvestri, Daniele; Mikšíček, Jiří; Waclawek, Stanislaw; Torres-Mendieta, Rafael; Padil, Vinod V. T.; Černík, MiroslavOver the last few years, the electrospinning technique has attracted significant attention for the production of novel nanofibrous materials. At the same time, the use of graphene oxide and the natural products extracted from plants and/or trees have become very popular in various fields of science. In this work, a new method for the production of nanofibers based on a combination of Gum Arabic (GA), as a natural tree gum exudate, PVA, as an environmentally-friendly stabilizer, and graphene oxide (GO) has been developed and characterized. SEM analysis showed fundamental differences on the surface of bare nanofibers with and without GO, and also significantly smaller fiber diameters in the case of the presence of GO (fibers <100 nm present). Raman spectroscopy confirmed and TGA analysis approximated the content of GO in the nanofibers. Adsorption of methylene blue on the produced nanofibrous membrane was about 50% higher in the presence of GO, which opens the possibility to use GO/GA/PVA fibers in several applications, for example for the removal of dyes.
- ItemRecycling non-food-grade tree gum wastes into nanoporous carbon for sustainable energy harvesting(ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND, 2020-02-21) Venkateshaiah, Abhilash; Cheong, Jun Young; Shin, Sung-Ho; Akshaykumar, K. P.; Yun, Tae Gwang; Bae, Jaehyeong; Waclawek, Stanislaw; Černík, Miroslav; Agarwal, Seema; Greiner, Andreas; Padil, Vinod V. T.; Kim, Il-Doo; Varma, Rajender S.The disposal of natural wastes has become a global problem and the use of lower-grade gums is very limited owing to their impurities as well as sticky nature. Rather than disposing these wastes, nanoporous carbon (nC) has instead been synthesized by carbonization and exfoliation. The synthesized nC exhibits a substantially high surface area along with abundant micro/mesopores. This desirable and useful nature of nC is well-suited for water-driven effective electrical energy conversion, which enables the fast evaporation of water via a capillary action through nanopores. Under asymmetric wetting in a water container and ambient conditions, the nC-based energy harvesters showed high capability of electricity production and reliable output generation, easily turning on a blue light-emitting diode (2.5 V and 20 mA) using a stored power source. In summary, many energy harvesters can be manufactured for the scale-up of electricity, and the suitability of regenerated carbon nanomaterials for green energy harvesting can contribute toward alleviating chronic environmental issues.
- ItemTree Gum-Graphene Oxide Nanocomposite Films as Gas Barriers(AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA, 2020-01-01) Venkateshaiah, Abhilash; Cheong, Jun Young; Habel, Christoph; Waclawek, Stanislaw; Lederer, Tomáš; Černík, Miroslav; Kim, Il-Doo; Padil, Vinod V. T.; Agarwal, SeemaTo reduce the dependency on petro-based conventional plastics, research focusing on bioplastics derived from biological origin has gained precedence. Herein, we report an ecofriendly and a facile synthetic route to develop a freestanding nanocomposite film prepared from the combination of nonedible biodegradable tree gum waste and graphene oxide (GO). Three variants of bionanocomposite films such as GO-gum arabic (GA-GO), GO-gum karaya (GK-GO), and GO- kondagogu gum (KG-GO) were fabricated via solution casting of respective gums with GO (0.5% and 1.0%) in an aqueous environment. GO was thoroughly blended within different types of gum matrices via the hydrogen bond interaction and electrostatic attraction, thus forming interconnected homogeneous GO-gum layered structure. Morphological analysis revealed a natural nacre-like structure comprised of gum-intercalated graphene sheets, which was further confirmed by X-ray diffraction studies. The addition of GO further transformed the brittle gum film into a freestanding film with substantial mechanical strength. Furthermore, the layered nanocomposite films demonstrated enhanced oxygen gas barrier property as well as reduced water vapor transmittance. The barrier properties are comparable to the plastics traditionally used in packaging, emphasizing the potential of tree gums nanocomposite films in packaging applications. Such frugally viable gums can be a cost-effective alternative in the development of nanocomposite films that could be readily used for applications in food packaging, pharmaceutical, and various biomedical industries.
- ItemUV-Catalyzed Persulfate Oxidation of an Anthraquinone Based Dye(MDPI, 2020-01-01) Krawczyk,Kamil; Wacławek, Stanisław; Kudlek, Edyta; Silvestri, Daniele; Kukulski, Tomasz; Grübel, Klaudiusz; Padil, Vinod V. T.; Černík, MiroslavWastewater from the textile industry has a substantial impact on water quality. Synthetic dyes used in the textile production process are often discharged into water bodies as residues. Highly colored wastewater causes various of problems for the aquatic environment such as: reducing light penetration, inhibiting photosynthesis and being toxic to certain organisms. Since most dyes are resistant to biodegradation and are not completely removed by conventional methods (adsorption, coagulation-flocculation, activated sludge, membrane filtration) they persist in the environment. Advanced oxidation processes (AOPs) based on hydrogen peroxide (H2O2) have been proven to decolorize only some of the dyes from wastewater by photocatalysis. In this article, we compared two very different photocatalytic systems (UV/peroxydisulfate and UV/H2O2). Photocatalyzed activation of peroxydisulfate (PDS) generated sulfate radicals (SO4•−), which reacted with the selected anthraquinone dye of concern, Acid Blue 129 (AB129). Various conditions, such as pH and concentration of PDS were applied, in order to obtain an effective decolorization effect, which was significantly better than in the case of hydroxyl radicals. The kinetics of the reaction followed a pseudo-first order model. The main reaction pathway was also proposed based on quantum chemical analysis. Moreover, the toxicity of the solution after treatment was evaluated using Daphnia magna and Lemna minor, and was found to be significantly lower compared to the toxicity of the initial dye.