Papers by Keyword: FTIR

Abstract: Glasses with chemical composition of (60-x)P₂O₅-25ZnO-(15+x)Li₂O with 0.0 ≤ x ≤ 5.0 mol % are prepared by melt quenching technique. The physical properties, by mean of density and molar volume are determined. The amorphous nature, absorption and structural behaviour are characterized using X-ray Diffraction (XRD), Ultraviolet-visible-near infrared (UV-Vis-NIR) and Fourier transform infrared (FTIR) respectively. In this work, the glass densities are found increases in the range of 2.70 - 2.78 gcm^-3 and molar volume decreases from 37.48 - 40.75 gcm^-3 with respect to Li₂O concentration. Meanwhile, the optical band gap energy for direct and indirect transition are found decreases from 3.074 eV to 2.525 eV and 2.699 eV to 1.670 eV respectively. The Urbach energy is varies as Li₂O content increases. The refractive index of these glasses is ranging from 2.48 to 2.90. FTIR spectra exhibited seven bands which centered at 512 cm⁻¹, 767 cm⁻¹, 918 cm⁻¹, 1087 cm⁻¹, 1281 cm⁻¹, 1627 cm⁻¹ and 3441 cm⁻¹ wavenumber that assigned as vibration of Zn-O, symmetric stretching vibration of P-O-P rings, asymmetric stretching vibration of P-O-P groups, asymmetric stretching of PO2-group, asymmetric stretching vibration P=O, bending vibration of water molecule and fundamental stretching of hydroxyl group.

Abstract: Silica borotellurite glasses doped with manganese oxide with chemical formula {[(TeO₂)_0.7(B₂O₃)_0.3­]_0.8[SiO₂]_0.2}_1-x{MnO₂}_x (where x = 0.0, 0.01, 0.02, 0.03, 0.04 and 0.05 molar fraction) were fabricated. Silica were extracted from the burning process of rice husk. Glass samples were prepared by using the melt-quenching technique. The FTIR spectra showed that the addition of MnO₂ contributed to the transformation of TeO₄ to TeO₃. The diffraction pattern of XRD showed a broad hump which indicates the amorphous nature of the samples. The result for both optical band gap and Urbach energy showed decreasing trend as the concentration of manganese increased.

Abstract: In this work, Hydrogenated silicon rich nitride (SRN) films were deposited by varying NH3/SiH4 ratio and thermally annealed within the temperature range of 700-1000 °C in N2 ambient to precipitate silicon nanocrystals in the film. The optical and structural properties of SiNx:H films were studied. Chemical composition and structural investigations were performed by Secondary ion mass spectrometry (SIMS), Infrared and Raman spectrometry experiments.Fourier Transform Infrared Spectroscopy (FTIR) indicates a new band which appeared as a “shoulder” in the 850-900 cm−1 range and is attributed to a reordering in the films towards an increased SiN4 bonding configuration resulting from the precipitation of silicon nanocrystals.The Raman analysis clearly evidences a high density of Si nanoclusters as shown by the broadened and asymmetric Raman peak approaching 520 cm-1.Strong visible photoluminescence (PL) can be observed in silicon nitride and the evolution of the photoluminescence with annealing temperature is correlated to the evolution of the structure. Radiative defects in the films and the quantum confinement effect in silicon nanoparticles were proposed to explain the origin of light emission from the samples.

Abstract: In this paper, the presence of calcium oxalate on calcareous stone, is studied. The patina consists mainly of calcium oxalate which exists in three forms: monohydrated whewellite (small, smooth, globular yellow-green to brown crystals radial fibrous) (COM), dehydrated weddelite (small crystals, and spherical clusters of plaques consisting of brown or yellow platelets, which are sharp) (COD) and trihydrate caoxite (rarely observed, as mono or dihydrated precursor forms)(COT). Scanning electron microscope with Energy Dispersive X-ray Spectroscopy (SEM/EDS), Fourier Transform Infrared spectroscopy (FTIR), Raman Spectroscopy are used for characterization. The oxalate films were found to form a thin compact non-porous shell and penetrate deeply in an intergranular position or along microfractures, with effects on longer stability.

Abstract: This paper reports studies to investigate the relationships between hydrophobicity of biochar surface and soil water retention. The studied biochars were produced from acacia wood, cashew wood and bamboo. The resulting materials were oxidized via liquid oxidation to generate hydrophilic biochars containing oxygenated functional groups on the surface. All biochars were characterized and their ability as soil additives to enhance water retention was assessed. Our results suggest that hydrophobicity/hydrophilicity of biochars is not the major factor governing water retention ability of this particular soil. However, hydrophilicity of biochar helps improve soil permeability by providing better wettability to the soil.

Abstract: Synthesis and characterization of bioglass^® of general composition (45-X-Y) SiO₂, 24.5 Na₂O, 24.5 CaO and 6.0 P₂O₅ (wt %) was modified by addition of X= (0-1) wt % of CeO₂ and Y= (0-1) wt % of La₂O₃ respectively. These five samples were prepared in alumina crucible via melting route at a temperature of 1400±5 °C with air as a furnace atmosphere. These glass samples were immersed in simulated body fluid (SBF) for different time period and their bioactivity were determined by Fourier transform infrared spectroscopy (FTIR) analysis. Surface morphology was studied by using Scanning electron microscope (SEM). Bioactivity, pH measurement of bioactive glass was carried out and mechanical properties of these glasses increased with increasing concentration of CeO₂ and La₂O₃.

Abstract: The isolation and characterization of nanocrystalline cellulose (NCC) from water hyacinth (WH) fibers were carried out. There are two treatments to obtain NCC from WH fibers by chemical and mechanical treatments. The chemical treatment involved alkalization with NaOH 25% in a highly-pressured tube, acid hydrolysis with 5M HCl, and bleaching with (NaClO₂:CH₃COOH) in ratio 5:2. The mechanical treatment was performed by using ultrasonic homogenizing at 12000 Rpm for 2 h. The morphological surface was observed by Transmission Electron Microscopy (TEM). TEM reported that the size of NCC was 10–40 nm. Crystallinity index and functional group analysis of the NCC WH fibers were also examined using X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. XRD reported that the crystallinity index increased significantly after chemical and mechanical treatment due to the presents of crystalline area in the WH fibers. The crystallinity index of raw fiber, digester, bleaching, and ultrasonic homogenizing were 7%, 68%, 69%, and 73% respectively. The content cellulose of final product was 68% as measured by the chemical composition test. Meanwhile, FTIR reported that WH fibers after being given chemical treatment lead the functional group change due to removal hemicellulose and lignin. The result of XRD and FTIR were indicated that the sample of NCC WH fibers presents the structure of cellulose crystal type I.

Abstract: The cerium dioxide films were prepared with cerium foils as raw materials by anodization in Na₂C₂O₄-NH₃∙H₂O-H₂O-(CH₂OH)₂ electrolyte. The anodic cerium oxide film was heat treated at 550°C. The cerium dioxide films were characterized with X-ray diffraction (XRD), energy-dispersive analyses of X-ray (EDAX), Fourier transform infrared (FTIR) techniques and scanning electron microcopy (SEM), respectively. The anodic cerium oxide film is semi crystalline film. The heat treated anodic cerium oxide film at 550°C is the fluorite-structured cerium dioxide film, and the crystal structure of the cerium dioxide film becomes more complete than that of the anodic cerium oxide film. The cerium dioxide film is porous film. The water, ethylene glycol and CO₂ are adsorbed in the anodic cerium oxide film. The adsorbing water, ethylene glycol and CO₂ in the anodic cerium oxide film are removed at 550°C. The cerium dioxide film has strong absorption in the range of 1400~4000cm^-1.

Abstract: This work reports the isolation and characterization of chitin from green algae using XRD, 13C CP/MAS NMR, FTIR and Microscopy. The XRD diffraction pattern confirmed orthorhombic structure of the crystalline polysaccharide, whereas the FTIR spectra revealed strong absorption bands at 896.9 cm-1 and 852 cm-1 typical of C–H axial and C–H equatorial vibrations within the anomeric center of the glucopyranosicyclic moiety. Another strong absorption band was observed at 1039.9 cm-1 and was assigned to C–O–C, C–O stretching bands. The purity and structure of the deacetylated chitin was confirmed using 13C NMR, showing overlapping peaks around 65 ppm assigned to both the sugar carbon at C2, as well as a methylene carbon at C6. An intense peak at 74 ppm is assigned to C3 and C5 with corresponding resonances at 81 and 104 ppm assigned to C4 and C1 respectively. Zeolite/Chitosan nanocomposites were synthesized by ionic cross-linking of chitosan with sodium tripolyphosphate. Chitosan nanoparticles and LTA of different concentrations were incubated with HeLa cancer cells to investigate their cytotoxicity effects. The exposure of the cells to chitosan nanoparticles resulted in a decreased in cell growth and this was concentration-dependent. Our results revealed the utility of locally available materials to produce new biodegradable nanoparticles to investigate their biological nanotoxicity.

Abstract: Transmission infrared spectroscopy (FTIR) was used to study the effect of the temperature and concentration of octadecylamine (surfactant) in the conformation state of amine chains incorporated in a bentonite matrix by organophilization process. The temperature is the most important factor in conformational changes-gauche/trans. Whereas the simultaneous increase of the temperature and concentration of surfactant favors the disordered conformation-gauche. This result is very important in the development of organo-bentonite based polymeric nanocomposites because the intercalation of the polymer in the galleries of the organo-bentonite is dependent on the conformation of the alkyl chains.