NOPR Community:

Construction of magnetic BiOBr@Fe3O4 hybrid nanoparticles via a sol-gel route for photocatalysis application

Mon, 01 Nov 2021 00:00:00 GMT

Title: Construction of magnetic BiOBr@Fe3O4 hybrid nanoparticles via a sol-gel route for photocatalysis application Authors: Song, Yunfeng; Zhang, Dongfang; Wang, Jiaxun Abstract: Development of a highly active visible-light-driven and magnetically recyclable photocatalyst is a challenge for chemical use of solar energy. In this study, Fe3O4 nanoparticles (NP), BiOBr and a superior magnetic separable BiOBr@Fe3O4 hybrid material have been synthesized via a facile chemical method. The structures, morphological, optical and physical properties of as-synthesized samples have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transforminfrared (FT-IR) spectroscopy, photoluminescence (PL) spectroscopy. The photocatalytic activity of the as-synthesized materials is evaluated by photocatalytic degradation of aromatic, heterocyclic organic compound such as methylene blue (MB) and 85% of MB could be removed by BiOBr@Fe3O4 hybrid within 60 min. It is found that the composite yield a significantly larger amount of hydroxyl radicals through free radical scavenging test. It is proposed that the observed synergistic effect between Fe3O4 and BiOBr is due to the charge transfer between the two oxides, improving the separation of the photogenerated charge carriers via the Z-scheme mechanism, and thus accelerating the photocatalytic degradation of MB and leading to high photocatalytic stability of BiOBr@Fe3O4 material. Page(s): 663-673

Functionalized polyacrylamide/graphite composites - Biodegradable adsorbents for the removal of synthetic dye from aqueous solution

Mon, 01 Nov 2021 00:00:00 GMT

Title: Functionalized polyacrylamide/graphite composites - Biodegradable adsorbents for the removal of synthetic dye from aqueous solution Authors: Kumarasamy, Gayathri; Samiyappan, Sathishkumar Abstract: Eco friendly, biodegradable functionalized polyacrylamide/graphite composites have been used to adsorb synthetic dye from aqueous medium. The polymer composites have been synthesized and characterized with FT-IR, 1H and 13C NMR. The composite’s adsorptive features have been analyzed using different parameters. The efficiency of adsorption process is determined using kinetic, equilibrium and thermodynamic analysis. The equilibrium uptake capacity was obtained from Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich models. The correlation coefficients indicate that the Langmuir model show satisfactory fit for the uptake of dye. The adsorption process follows pseudo second order in addition to intraparticle diffusion model with a good correlation coefficient. The thermodynamic parameters ΔG, ΔH and ΔS show that the adsorption process is spontaneous (ΔG < 0), endothermic (ΔH > 0) and had decreased entropy (ΔS > 0). The equilibrium and kinetic experiments confirm that the temperature and pH play an important role i.e., the dye uptake increases with increased temperature and decreased pH. FTIR and desorption studies confirm the involvement of functional groups in adsorption mechanism. Page(s): 674-683

Efficient removal of Cr (VI) using raw and phosphoric acid modified Sterculia Alata nutshell

Mon, 01 Nov 2021 00:00:00 GMT

Title: Efficient removal of Cr (VI) using raw and phosphoric acid modified Sterculia Alata nutshell Authors: Nawaz, Ahmad; Singh, Bineeta; Kumar, Pradeep Abstract: The adsorption behaviour of Cr (VI) onto raw Sterculia Alata nutshell (RSN) and phosphoric acid modified Sterculia Alata nutshell (PSN) from aqueous solution has been studied. Specific constraints such as initial pH (2-12), adsorbent dose (0.4-3.2 g/L) and temperature (24-32°C) have been investigated to examine the optimum process parameter for adsorption. Both the biosorbents are characterized based on their physicochemical characterization such as FTIR, SEM-EDS and XRD. The adsorption characteristics were assessed using the isotherms (Langmuir and Freundlich) to match the adsorption details. The maximum chromium adsorption capacity is obtained to be 39.89mg/g and 88.30mg/g for RSN and PSN at 28°C respectively. Both the biosorbents confirmed the aptness of pseudo second order kinetics throughout the chromium (VI) abstraction phase with R2 value greater than 0.99. Page(s): 684-692

Optical characterization of different oxide nanomaterials dispersed PVA/PEO blend matrix-based hybrid polymer nanocomposites for advances in optoelectronic device technologies

Mon, 01 Nov 2021 00:00:00 GMT

Title: Optical characterization of different oxide nanomaterials dispersed PVA/PEO blend matrix-based hybrid polymer nanocomposites for advances in optoelectronic device technologies Authors: Dhatarwal, Priyanka; Choudhary, Shobhna; Sengwa, R J Abstract: Optical properties of different oxide nanomaterials (viz. zinc oxide (ZnO), tin oxide (SnO2), silica (SiO2), and alumina (Al2O3)) as nanofillers (NFs) and a host polymer matrix of poly(vinyl alcohol) (PVA)/poly(ethylene oxide) (PEO) blend based hybrid polymer nanocomposites (HPNCs) have been investigated by employing ultraviolet-visible (UV-Vis) spectroscopy. The UV-Vis absorbance spectra over the photons wavelength range 200-800 nm, and the absorption coefficient, energy bandgap, and Urbach energy of the PVA/PEO/NFs HPNC films are determined and reported. The dependence of the optical characteristics of these HPNCs on the type of oxide nanofillers and their concentration have been studied which is found correlated with the optical properties of the nanofillers. Considering the results, suitability of PVA/PEO/NFs materials as potential candidates for UV-shielder, light diffuser, bandgap tuner, and photo-sensor/detector in the design and evolution of various flexible-type optoelectronic devices/components have been discussed. Page(s): 693-700