School Of Basic And Applied Sciences
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Item Adsorption and Activation of CO2on Small-Sized Cu-Zr Bimetallic Clusters(American Chemical Society, 2021-03-17T00:00:00) Megha; Mondal, Krishnakanta; Ghanty, Tapan K.; Banerjee, ArupAdsorption and activation of CO2 is a key step in any chemical reaction, which aims to convert it to other useful chemicals. Therefore, it is important to understand the factors that drive the activation process and also search for materials that promote the process. We employ the density functional theory to explore the possibility of using small-sized bimetallic Cu-Zr clusters, Cu4-nZrn, with n = 1-3 for the above-mentioned key step. Our results suggest that after adsorption, a CO2 molecule preferably resides on Zr atoms or at the bridge and triangular faces formed by Zr atoms in bimetallic Cu-Zr clusters accompanied with its high degree of activation. Importantly, maximum activation occurs when CO2 is adsorbed on the CuZr3 cluster. Interestingly, we find that the adsorption energy of CO2 can be tuned by varying the extent of the Zr atom in Cu-Zr clusters. We rationalize the high adsorption of CO2 with the increase in the number of Zr atoms using the d-band center model and the concept of chemical hardness. The strong chemisorption and high activation of CO2 are ascribed to charge migration between Cu-Zr clusters and the CO2 molecule. We find an additional band in the infrared vibrational spectra of CO2 chemisorbed on all of the clusters, which is absent in the case of free CO2. We also observe that the energy barriers for the direct dissociation of the CO2 molecule to CO and O decrease significantly on bimetallic Cu-Zr clusters as compared to that on pure Cu4. In particular, the barrier heights are considerably small for Cu3Zr and CuZr3 clusters. This study demonstrates that Cu3Zr and CuZr3 clusters may serve as good candidates for activation and dissociation of the CO2 molecule. � 2021 American Chemical Society.Item Synergistic effect of pistachio shell powder and nano-zerovalent copper for chromium remediation from aqueous solution(Springer Science and Business Media Deutschland GmbH, 2021-07-06T00:00:00) Kumar, Sandeep; Brar, Ravinderdeep Singh; Babu, J. Nagendra; Dahiya, Amarjeet; Saha, Sandip; Kumar, AvneeshPistachio shell powder supported nano-zerovalent copper (ZVC@PS) material prepared by borohydride reduction was characterized using SEM, FTIR, XRD, TGA/DTA, BET, and XPS. SEM, XRD, and XPS revealed the nano-zerovalent copper to consist of a core-shell structure with CuO shell and Cu(0) core with a particle size of 40�100 nm and spherical morphology aggregated on PS biomass. ZVC@PS was found to contain 39% (w/w %) Cu onto the pistachio shell biomass. Batch sorption of Cr(VI) from the aqueous using ZVC@PS was studied and was optimized for dose (0.1�0.5 g/L), initial Cr(VI) concentration(1�20 mg/L), and pH (2�12). Optimized conditions were 0.1 g/L doses of sorbent and pH=3 for Cr(VI) adsorption. Langmuir and Freundlich adsorption isotherm models fitted well to the adsorption behavior of ZVC@PS for Cr(VI) with a pseudo-second-order kinetic behavior. ZVC@PS (0.1g/L) exhibits qmax for Cr(VI) removal up to 110.9 mg/g. XPS and other spectroscopic evidence suggest the adsorption of Cr(VI) by pistachio shell powder, coupled with reductive conversion of Cr(VI) to Cr(III) by ZVC particles to produce a synergistic effect for the efficient remediation of Cr(VI) from aqueous medium. Graphical abstract: [Figure not available: see fulltext.] � 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Functional characterization of microbes and their association with unwanted substance for wastewater treatment processes(Elsevier Ltd, 2023-07-06T00:00:00) Swapnil, Prashant; Singh, Laishram Amarjit; Mandal, Chandan; Sahoo, Abhishek; Batool, Farida; Anuradha; Meena, Mukesh; Kumari, Pritee; Harish; Zehra, AndleebNowadays, microorganisms can be used to eliminate a variety of pollutants such as toxic metal ions from wastewater. These emergences of harmful elements in wastewater, high-priced cultivation of microbes and technical hitches in industrial scale production appeared as main challenges for thriving coupling of microbes with wastewater. These microbes serve as potential sorbents by following suitable adsorption mechanisms. There are some photobioreactors have been also mentioned in this review which is based on microbial biofilm and emerged as an alternative technology to predictable photosynthetic systems for treatment of wastewater based on biomass production at low cost. Bioremediation using different microbes showed contrast results to remove heavy metals from wastewater. Microorganism such as Nostoc sp., Aspergillus versicolor, Aspergillus lentulus and Aspergillus niger remediate 99.6, 99.89, 99.7 and 98 % of Pb, Cr, Cu and Ni, respectively. In this review, mechanistic approaches and distinct pathways of the microbes for removal of various inorganic and organic compounds from wastewater have been methodically discussed. We have also discussed some major commercial production challenges such as techno-economic feasibility genetic engineering research and biorefinery approach. Overall the review discussed the microbial biodiversity in wastewater and their role in remediation of wastewater and their ability to be a potent candidate headed for sustainable industrial wastewater treatment applications through different approaches such as phytoremediation and bioremediation. This article provides valuable insights into multiple aspects of environmental biotechnology, including photobioreactors, metal uptake capacity of microorganisms, heavy metal contamination and its effects and bioremediation using molecular approaches and wastewater treatment through phytoremediation. Moreover, it contributes to our understanding of these topics and can help in the development of sustainable solutions for environmental remediation and pollution control in wastewater though microorganisms. � 2023 Elsevier LtdItem Functional characterization of microbes and their association with unwanted substance for wastewater treatment processes(Elsevier Ltd, 2023-07-06T00:00:00) Swapnil, Prashant; Singh, Laishram Amarjit; Mandal, Chandan; Sahoo, Abhishek; Batool, Farida; Anuradha; Meena, Mukesh; Kumari, Pritee; Harish; Zehra, AndleebNowadays, microorganisms can be used to eliminate a variety of pollutants such as toxic metal ions from wastewater. These emergences of harmful elements in wastewater, high-priced cultivation of microbes and technical hitches in industrial scale production appeared as main challenges for thriving coupling of microbes with wastewater. These microbes serve as potential sorbents by following suitable adsorption mechanisms. There are some photobioreactors have been also mentioned in this review which is based on microbial biofilm and emerged as an alternative technology to predictable photosynthetic systems for treatment of wastewater based on biomass production at low cost. Bioremediation using different microbes showed contrast results to remove heavy metals from wastewater. Microorganism such as Nostoc sp., Aspergillus versicolor, Aspergillus lentulus and Aspergillus niger remediate 99.6, 99.89, 99.7 and 98 % of Pb, Cr, Cu and Ni, respectively. In this review, mechanistic approaches and distinct pathways of the microbes for removal of various inorganic and organic compounds from wastewater have been methodically discussed. We have also discussed some major commercial production challenges such as techno-economic feasibility genetic engineering research and biorefinery approach. Overall the review discussed the microbial biodiversity in wastewater and their role in remediation of wastewater and their ability to be a potent candidate headed for sustainable industrial wastewater treatment applications through different approaches such as phytoremediation and bioremediation. This article provides valuable insights into multiple aspects of environmental biotechnology, including photobioreactors, metal uptake capacity of microorganisms, heavy metal contamination and its effects and bioremediation using molecular approaches and wastewater treatment through phytoremediation. Moreover, it contributes to our understanding of these topics and can help in the development of sustainable solutions for environmental remediation and pollution control in wastewater though microorganisms. � 2023 Elsevier LtdItem Zirconia nanoparticles/ferroelectric liquid crystal composites for ionic impurity-free memory applications(2013) Chandran, A.; Prakash, J.; Ganguly, P.; Biradar, A.M.We observed an ionic impurity-free memory effect using a zirconia nanoparticles (ZNPs)/ferroelectric liquid crystal (FLC) composite. The pure and ZNPs doped FLC cells have been analyzed by means of dielectric spectroscopy, polarizing optical microscopy and electrical resistance/conductivity measurements. The memory behavior in ZNPs/FLC composite was confirmed by dielectric dispersion, electrical, and optical studies, whereas dielectric loss spectra confirmed the disappearance of the low-frequency relaxation peak, which appears due to the presence of ionic impurities in FLC materials. The observed memory effect has been attributed to minimization of the depolarization field and ionic charges, whereas the reduction of ionic effects has been attributed to the strong adsorption of ionic impurities on the surface of ZNPs. The ZNPs dispersed in FLCs may play a role in trapping the impurity ions (minimize the depolarization fields) under applied voltage and cause a better memory effect in ZNPs doped FLC material. Moreover, the ion adsorption capability of ZNPs is found to be almost independent of temperature as the value of resistance did not change remarkably on increasing the temperature. The reduction of ionic impurities of FLCs by doping ZNPs did not show degradation over time, as we repeated the experiments on the same sample cells after many days and did not find ionic effects in the ZNPs doped FLC materials. These studies would be helpful to provide an idea for designing ionic impurity-free memory devices. ? 2013 The Royal Society of Chemistry.