Browsing by Author "Singh, Janpreet"

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    Evaluation of synergistic adsorption approach for terbinafine removal by cotton shell powder immobilized zerovalent copper: Adsorption kinetics and DFT simulation
    (Elsevier B.V., 2023-08-30T00:00:00) Kaur, Parminder; Hussain, Khadim; Kumar, Atul; Singh, Janpreet; Nagendra Babu, J.; Kumar, Sandeep
    Cotton shell powder (CS), nano zerovalent copper (nZVC) and cotton shell powder immobilized zerovalent copper (ZVC@CS) were evaluated for their adsorption efficiencies towards terbinafine hydrochloride (TBH), an antifungal drug. The nZVC and ZVC@CS synthesized via one pot redox precipitation method were characterized by FTIR, XRD, BET, FESEM and TGA analysis. The TGA and AAS analysis confirmed the loading of nearly 10% of nZVC on cotton shell powder in ZVC@CS. The effect of operational parameters (pH, adsorbent dose, initial drug concentration, time, etc.) determining the extent of terbinafine hydrochloride adsorption on ZVC@CS were investigated to ascertain the optimal experimental conditions to achieve maximum adsorption efficiencies. To investigate the adsorption behavior of TBH on ZVC@CS, the experimental data were fitted for five different adsorption models viz. Langmuir, Freundlich, Temkin, Redlich-Peterson and Hill isotherms. The TBH adsorption data was best fit with Hill isotherm model indicating cooperative sorption of TBH molecules on ZVC@CS surface. Among the five kinetic equations namely the pseudo-first-order (PFO), the pseudo-second-order (PSO), Elovich model, the intraparticle diffusion model, and Boyd kinetic model used to estimate the adsorption mechanism, the PFO kinetic model give best fit with a good correlation for the physisorption of TBH on ZVC@CS composite. The mechanism of the adsorption process was observed to be complex, consisting of both surface adsorption and pore diffusion. However, the Boyd plot confirms external mass transport as the rate limiting step for the adsorption of TBH on ZVC@CS. The synergistic adsorption of TBH on ZVC@CS was hypothesized, and the idea was supported by structure optimization results from DFT studies. The ZVC@CS exhibits equilibrium TBH adsorption efficiency (qmax) of 285.3 mg.g?1, significantly higher than adsorbents used in literature for the TBH removal. It is suggested that ZVC@CS may serve as sustainable adsorbents for the removal of cationic contaminants from acidic medium. � 2023 Elsevier B.V.
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    Identifying the preferred interaction mode of naringin with gold nanoparticles through experimental, DFT and TDDFT techniques: Insights into their sensing and biological applications
    (Royal Society of Chemistry, 2016) Singh, Baljinder; Rani, Monika; Singh, Janpreet; Moudgil, Lovika; Sharma, Prateek; Kumar, Sanjeev; Saini, G.S.S.; Tripathi, S.K.; Singh, Gurinder; Kaura, Aman
    In this work, the binding behaviour of naringin-a flavonoid with AuNPs is explained by combining experimental and theoretical approaches. We have systematically analysed the effect of temperature and concentration of naringin and gold (Au) in the formation of naringin stabilized Au nanoparticles (N-AuNPs). The interaction of naringin with gold nanoparticles (AuNPs) is investigated by various techniques such as UV-visible spectroscopy, TEM, FT-IR, XRD and gel electrophoresis. These studies indicate that naringin acts as a reducing and stabilizing agent. Further, we have modelled the two side chains of naringin with the functional groups [C10H7O2] and [C6H5O]-, and identified the lowest energy configurations of these groups with AuNPs with the help of density functional theory (DFT). The [C10H7O2]-Au13 has higher binding energy than [C6H5O]--Au13 and it is attributed to delocalized molecular orbitals in [C10H7O2], hence higher charge transfer to the Au13 cluster. On the basis of the resulting structures, we examine the optical properties using time-dependent density functional theory (TDDFT). We observe significant changes in the optical spectra of the representative structures of side chains with the AuNPs. The peak in the spectra of the Vis region of [C10H7O2]-Au13 undergoes a shift towards lower wavelength in comparison to [C6H5O]--Au13. Natural transition orbitals (NTOs) of hole and particle states of the [C10H7O2]-Au13 conjugate system are localized on [C10H7O2] and Au13, respectively, whereas for the [C6H5O]--Au13 both hole and particle states are localized on the Au13 cluster. These N-AuNPs show their applicability as a sensor for detecting aluminium ions (Al3+) in aqueous solution. These NPs are also found to be biocompatible with normal red blood cells and MDAMB-231 breast carcinoma cell lines, as evaluated from hemolysis and cytotoxicity assays. Thus, naringin offers non-toxic and bio friendly N-AuNPs, which are considered to be the best vehicle for drug release and other possible biomedical and sensing applications. ? 2016 The Royal Society of Chemistry.