Browsing by Author "Somasekhara Rao, T."

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    Removal of toxic arsenic from aqueous media using polyphenylsulfone/cellulose acetate hollow fiber membranes containing zirconium oxide
    (Elsevier B.V., 2020) Kumar, M.; Isloor, A.M.; Somasekhara Rao, T.; A.F., A.F.; Farnood, R.; Nambissan, P.M.G.
    Arsenic is one of the highly dangerous metalloid present in the polluted water, it's effective and economical removal is one of the major challenges to the researchers. It was planned to prepare hollow fiber membranes using polyphenylsulfone (PPSU) as a polymer, cellulose acetate (CA) and cellulose acetate phthalate (CAP) as additives with increased dosages (0.6, 1 and 1.5 wt%) of zirconium oxide (ZrO2) nanoparticle. The fabricated hollow fiber membranes were characterized by SEM, AFM, zeta potential, ATR-FTIR and XPS to analyze the membrane's morphologies (cross-section and surface), topography, surface charge and assessment of different functional groups. As used ZrO2 was characterized by TEM and XRD to analyze the morphology and crystallinity. The positron annihilation lifetime spectroscopy (PALS) analysis was carried out for neat and ZrO2 contained membranes, to study the expansion of free-volume in membrane morphology. Leaching studies of the used zirconium with respect to different pH from the ZrO2 contained hollow fiber membrane was also examined. The enhancement of membrane hydrophilicity was confirmed by contact angle, porosity, water uptake and pure water permeability measurements. Membranes prepared by 1 wt% of ZrO2 in PPSU/CA (PZCA-1) and 0.6 wt% of ZrO2 in PPSU/CAP (PZCAP-0.6) were proved to be efficient as arsenic removal membranes (i.e. PZCA-1 as 87.24% and PZCAP-0.6 as 70.48% and permeability of 89.94 L/m2h bar and 70.59 L/m2h bar respectively) using lab-prepared 1 ppm standard arsenic solution at pH range of 6.8 ± 0.2. Also, there is a decrease in the arsenic removal tendency was observed with the excessive dosages of ZrO2, which is due to the concentration polarization on surfaces of the membranes. Antifouling behavior of the prepared hollow fiber membranes was also studied using bovine serum albumin (BSA). © 2020
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    Self-powered flexible piezoelectric nanogenerator made of poly (vinylidene fluoride)/Zirconium oxide nanocomposite
    (Institute of Physics Publishing helen.craven@iop.org, 2019) Naik, R.; Somasekhara Rao, T.
    The electroactive ?-phase is the most desirable due to its highest piezo-, pyro-, and ferroelectric properties in Poly (vinylidene fluoride) (PVDF). The ?-phase can be nucleated by incorporation of nanoparticles into PVDF. The objective of this study is the preparation and characterization of the pristine PVDF film, and intensified dosages of the ZrO2 modified composite PVDF films, further piezoelectric properties of nanocomposites films are evaluated. The nanocomposite films have been prepared by solution casting method with different loadings of ZrO2. The prepared films are characterized by Scanning electron microscope (SEM), x-ray diffraction (X-RD) analysis, Fourier transform infrared spectra (FTIR), and Differential scanning calorimetry (DSC), to study surface morphology, ?-phase content, crystallinity, and melting temperature. The experimental analysis shows that the ?-phase percentage and melting temperature of the films increases with ZrO2 loading, but the percentage of crystallinity decreases. Nanogenerators are fabricated by using the films, and piezoelectric performances of the nanogenerators are evaluated under various external stresses. The maximum voltage generated in the case of 5 wt% loading of ZrO2 is 1560 mV for 100 g of load, which is approximately eight times higher than the voltage generated in the pristine-PVDF and 2.2 V is generated while tapping by hand. © 2019 IOP Publishing Ltd.