Powder Fourier Transform Infrared Research Articles

Effects of Ca<sup>2+</sup>/Mg<sup>2+</sup> ions in recycled water on the reverse flotation properties of iron oxides

Water quality, particularly hardness, plays an important role in affecting the floatability of minerals as it interferes with the chemical/electro-chemical characteristics of mineral surfaces and their interactions with flotation reagents. It could become unpredictable when water sources characterized by different calcium or magnesium ion distributions were involved. This study aimed to identify the role of Ca<sup>2+</sup>/Mg<sup>2+</sup> ions in the recycled water on the cationic reverse flotation selectivity of iron oxides through a series of bench/micro flotation tests, zeta potential, powder contact angle, and Fourier Transform Infrared (FTIR), etc. The results pointed out that the use of recycled tailing water deteriorates the flotation selectivity and dilutes the concentrates. This can be largely attributed to the presence of Ca<sup>2+</sup> ions at higher concentrations as they induce a drop in the Fe recovery and an increase in SiO2 content while an increase in the content of Mg<sup>2+</sup> ions seems to have little effect on the quality of concentrate. As evidenced by the data from micro-flotation, powder contact angle, zeta potentials, and FTIR, a hydrophilic colloidal layer formed by Ca-based hydrolyzed compounds, such as Ca(OH)<sup>+</sup> or, CaCO<sub>3(s)</sub>, etc., on quartz could change its zeta potentials and disturb its interactions with a cationic collector. They also play a role in weakening the flocculation of starch on hematite probably by pre-locking the acidic groups on the starch remnants and contracting their configurations, thus preventing their adsorption on mineral surfaces. However, magnesium ions seem to be beneficial to in strengthening the flocculation of starch on hematite as magnesium-based species could act as adsorption bridges of between starch and mineral surfaces.

IMPORTANCE OF THE COLOR TEMPERATURE IN COLD WHITE LIGHT EMISSION OF Ca2MgSi2O7: Dy3+ PHOSPHOR

A promising candidate of white light-emitting (Ca2MgSi2O7: Dy3+) phosphor was successfully synthesized via traditional high-temperature solid-state synthesis technique using boric acid (H3BO3) as a fuel. The synthesized material sample was characterized with the help of powder X-ray diffraction (PXRD), FT-IR (Fourier Transform Infra-red) Spectroscopy, FESEM (Field Emission Scanning Electron Microscopy) and PL (Photoluminescence) spectra. Using the Debye-Scherer formula and UDM method, the crystallite size and crystal lattice strain were evaluated, respectively. Photoluminescence (PL) properties (both excitation & emission spectra) for the prepared phosphor were systematically investigated in detail. Photoluminescence spectra were revealed that the strong transition of spectral emission lines centered at 484nm (blue), 578nm (yellow) and weak transition of spectral emission lines centered at 615nm (red) wavelength. These peaks were assigned to following transitions (4F9/2 → 6H15/2,13/2,11/2), which are responsible for the (f→f) transitions from the ground level (lower energy state) to excited level (higher energy state) in the 4f9electronic configuration of dopant [Dy3+] ions. CIE color chromaticity coordinates and Color Correlated Temperature (CCT) of synthesized Ca2MgSi2O7: Dy3+ phosphor sample is well suited for the generation of cold white light emission with a CIE coordinate value of (X = 0.31, Y = 0.32) and CCT value also calculated as 5167K. Here upon, it is highly applicable to be a novel hopeful phosphor for cold WLEDs.

Discrete Arsonate-Grafted Inverted-Keggin 12-Molybdate Ion [Mo12O32(OH)2(4-N3C2H2-C6H4AsO3)4]2- and Formation of a Copper(II)-Mediated Metal-Organic Framework.

The discrete inverted-Keggin ion [Mo12O32(OH)2(4-N3C2H2-C6H4AsO3)4]2- (1) has been prepared in an aqueous acidic (pH 0.8) medium by the reaction of MoO3 with the (4-triazolylphenyl)arsonic acid 4-N3C2H2-C6H4AsO3H2 under hydrothermal conditions and was isolated as a sodium salt in 21% yield. The exact same reaction in the presence of Cu2+ ions resulted in the neutral metal-organic framework (MOF) Cu2[Mo12O34(4-N3C2H2-C6H4AsO3)4] (Cu-1) in 68% yield. The inverted-Keggin ion 1 comprises a metal-oxo core, which is capped by four organoarsonate groups, and in Cu-1, individual polyanions are linked in the solid state by coordination of the Cu2+ ions with the triazolyl groups. The discrete ion 1 was characterized by single-crystal X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and atomic absorption (AA) spectroscopy, as well as thermogravimetric analysis (TGA), and the POM-MOF Cu-1 was characterized by single-crystal and powder XRD, FT-IR, TGA, and gas sorption. Cu-1 has channels with a diameter of around ∼0.9 nm and exhibits a water-vapor adsorption capacity of 89.7 cm3 g-1 (p/p0 = 0.95).

New Insight into the Relationships Between Structural and Ftir Spectroscopic Features of Kaolinites

AbstractTo resolve the existing ambiguities in the interpretation of the OH-stretching vibrations of kaolinites, relationships were, for the first time, established between the structural and Fourier-transform infrared (FTIR) spectroscopic features for a set of kaolinite samples which differed in terms of their relative amounts of coexisting high- and low-ordered phases. For this purpose, a representative collection of kaolinites differing in origin, particle size, and degree of disorder was studied by powder X-ray diffraction (XRD) and FTIR spectroscopy. Modeling of the experimental XRD patterns based on the orthogonal layer unit cell having a mirror plane showed each sample to be a mixture of nearly defect-free high-ordered (HOK) and low-ordered (LOK) kaolinite phases, with HOK varying from 86 to 4%. The wavenumbers, heights, areas, and full widths at half-maximum (FWHM) were determined for the OH-stretching bands at ~3697 (ν1), ~3670 (ν2), ~3652 (ν3), and 3620 cm–1 (ν4) by decomposition and fitting of the FTIR spectra. The FWHM(ν1)/FWHM(ν4) and FWHM(ν3)/FWHM(ν2) values were related linearly to the HOK content, which may be associated with the in-phase and out-of-phase character of the corresponding pairs of vibrations, respectively. A novel interpretation was suggested for the variations in the relative integrated intensities of the OH bands with the amount of the HOK phase. The intensity distribution of the ν2 and ν3 bands is controlled by the triclinic structure symmetry in the defect-free kaolinite and the mirror symmetry of the layers in low-ordered structures, in agreement with the observed evolution of the corresponding band intensities. The ν1 and ν2 band positions for the low-ordered samples are within the wavenumber range for the high-ordered samples. In contrast, the ν3 and ν4 band positions for the low-ordered samples are shifted toward higher wavenumbers, indicating that some of the low-ordered kaolinites should contain dickite-like structural fragments distributed among kaolinite layers.

Structural Elucidation and Position Identification of Cu(II) ion in Hexaaquazinc(diaquabismalonto)zincate: Single Crystal EPR and Optical Studies

Single crystal electron paramagnetic resonance (EPR), powder X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) and UV–Visible (UV–Vis) spectroscopy studies of Cu(II) doped in hexaaquazinc(diaquabismalonto)zincate (HZDMZ) have been investigated at room temperature. Angular variation of copper hyperfine lines in the three orthogonal planes shows the presence of a single site in substitutional position, with spin Hamiltonian parameters calculated from EPR spectra are gxx = 2.3940; gyy = 2.0919; g-zz = 2.0700; A–xx = 13.85 mT; Ayy = 1.79 mT; Azz = 1.39 mT. Molecular orbital coefficients β2 = 0.765 and e2 = 0.275 have been calculated, which reveal a moderately covalent metal–ligand bond. Optical and EPR data have been collaborated to obtain crystal field parameters, admixture and molecular orbital coefficients. Powder XRD, FT-IR and UV–Vis data confirms the structure of host complex and presence of the dopant.

Characterization of calcium-containing phases in alkali-activated municipal solid waste incineration bottom ash binder through chemical extraction and deconvoluted Fourier transform infrared spectra

Abstract It has been reported that municipal solid waste incineration bottom ash (IBA) can be a potential precursor for alkali-activated materials (AAM). This study investigates chemical composition and structure of calcium-containing phases in an alkali-activated IBA (AA-IBA) binder by a novel combination of selective chemical extraction and Fourier transform infrared (FTIR) spectral subtraction and deconvolution. Salicylic acid/methanol extraction is used to isolate the calcium-containing phases from the AA-IBA binder. X-ray powder diffraction and FTIR spectroscopy are used for sample characterization. Spectral subtraction is carried out to assign FTIR peaks of calcium-containing phases and deconvolution is used to discover various individual Si-O peaks hidden in the single broad FTIR peak. Results show that the AA-IBA consists of about 20 wt.% calcium silicate hydrate (C-S-H) and pirssonite (Na2Ca(CO3)2·2H2O). Chemical structure of the C-S-H in AA-IBA is found to be broadly similar to that in aged Portland cement paste, with possibly a higher degree of polymerization of the silicate chains. The methodology established in this study is significant and can greatly benefit the development of sustainable construction materials because many industry by-products and solid wastes are Si and/or Al rich, which could be potential AAM precursor.

Synthesis, modification, characterization and application of AC@Fe 2 O 3 @MnO 2 composite for ultrasound assisted dispersive solid phase microextraction of refractory metals in environmental samples

Activated carbon-coated iron oxide @ manganese oxide nanoparticles ([email protected]2O3@MnO2) were synthesized by sol-gel method. Activated carbons (AC) were prepared from tyres after carbonization at 900 °C and chemically activated using H2O2. The composite was characterized by scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM), X-ray powder diffraction (XRD), nitrogen adsorption and FTIR. The Fourier Transform Infrared (FTIR) confirmed the presence of carboxyl and hydroxyl groups on the surface of AC. In addition, the TEM, SEM/EDS and XRD revealed attractive properties of the composite which further confirmed the union of metal oxide nanoparticles with the surface of AC. The composite was used as an adsorbent for ultrasound assisted dispersive solid phase microextraction (UA-DSPME) of Ge, Hf, Mo, Nb, Sb, Ta, Te, Sn, Ti, W and Zr in environmental water samples. Under optimized conditions, the limits of detection and quantification ranged 0.0004–0.02 μg L−1 and 0.001–0.07 μg L−1, respectively. The precisions expressed in terms of the relative standard deviation (%RSD) were less than or equal to 5.2%. The developed adsorbent was applied in real water samples. The results obtained by the developed method were not statistically different with those obtained by the reference method.

Sol–Gel Synthesis and Characterization Studies of NiMoO<SUB>4</SUB> Nanostructures for Photocatalytic Degradation of Methylene Blue Dye

Nanostructured nickel molybdate (NiMoO4) nanoparticles (NPs) were successfully synthesized by using nickel nitrate and ammonium molybdate as the precursors and citric acid as the fuel by a simple modified sol-gel method. The prepared samples were characterized by powder X-ray diffraction (XRD), Fourier transform Infrared (FT-IR) spectra, high resolution scanning electron microscope (HR-SEM), energy dispersive X-ray (EDX), UV-Visible diffuse reflectance spectra (DRS), photoluminescence (PL) spectra and vibrating sample magnetometer (VSM) techniques. Powder XRD, FT-IR and EDX results were confirmed that the resultant powders was pure and single phase crystalline with monoclinic structure. HR-SEM images show that the morphology of the obtained powder consist nanostructued particles-like morphology. VSM results showed ferromagnetic behavior of the samples. Photo-catalytic activity of NiMoO4 NPs was tested for the photo-catalytic degradation (PCD) of methylene blue (MB) and it was found that higher PCD efficiency.

Sesamum indicum Plant Extracted Microwave Combustion Synthesis and Opto-Magnetic Properties of Spinel MnxCo₁₋xAl₂O₄Nano-Catalysts.

Spine Mn(x)Co₁₋xAl₂O₄ (x = 0, 0.3 and 0.5) nanoparticles were synthesized using Sesamum indicum (S. indicum) plant extracted microwave-assisted combustion method. S. indicum plant extract simplifies the process, provides an alternative process for a simple, economical and environment friendly synthesis. The absence of surfactant/catalysts has led to a simple, cheap and fast method of synthesis of spinel nanoparticles. The as-synthesized spinel nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, high resolution scanning electron microscopy (HR-SEM), high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), Brunauer Emmett Teller (BET) surface area analysis, UV-Visible diffuse reflectance spectroscopy (DRS), Photoluminescence (PL) spectroscopy, and vibrating sample magnetometer. The formation of spinel nanoparticles was confirmed by HR-SEM and HR-TEM and their possible formation mechanisms were also proposed. Powder XRD, FT-IR, SAED and EDX results confirmed the formation of pure and single cubic phase CoAl₂O₄ with well-defined crystalline. The optical property was determined by DRS and PL spectra. VSM measurements revealed that pure and Mn-doped CoAl₂O₄ samples have weak ferromagnetic behavior and the magnetization values increases with increasing the concentration of Mn²⁺ ions in the CoAl₂O₄ lattice. The sample Mn₀.₅Co₀.₅Al₂O₄ possessed higher surface area and smaller crystallite size than other samples, which led to enhance the performance toward the selective oxidation of benzyl alcohol into benzaldehyde.

Magneto-Optical and Catalytic Properties of Recyclable Spinel NiAl 2 O 4 Nanostructures Using Facile Combustion Methods

Spinel nickel aluminate (NiAl 2 O 4) nanospheres (NSPs) and nanoplatelets (NPLs) were successfully synthesized using a facile microwave combustion method (MCM) and conventional combustion method (CCM), respectively, using urea as the fuel. The as-prepared samples were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high-resolution scanning electron microscopy (HR-SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDX), selected area electron diffraction (SAED), UV–Visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, and vibrating sample magnetometer (VSM) analysis. Powder XRD, FT-IR, EDX, and SAED results showed that the samples were pure phase spinel NiAl 2 O 4 nanocrystals without any other secondary phase impurity. UV–Vis DRS and PL spectroscopy results were used to calculate the energy band gap (E g) value of the samples which is 3.41 and 3.08 eV for NiAl 2 O 4 NSPs and NiAl 2 O 4 NPLs, respectively. VSM results of the NiAl 2 O 4 NPLs sample show lower M s (49.16 × 10 −3 emu/g) values compared with the NiAl 2 O 4 NSPs sample (73.42 × 10 −3 emu/g), which confirm that both the products have ferromagnetic behavior. NiAl 2 O 4 NSPs were found to have higher surface area than NiAl 2 O 4 NPLs, which in turn leads to the improved performance towards the selective oxidation of benzyl alcohol into benzaldehyde, with 100 % selectivity, and it was found that the NiAl 2 O 4 NSPs sample show higher conversion (96.25 %) than NiAl 2 O 4 NPLs (85.37 %). The as-prepared samples show high activity, good reusability, remarkable stability, and environmentally friendly materials for industrial and technological applications.

Polarization Imaging and Characterization of Chitosan for applications in tissue engineering

In this study we described the optical properties of Chitosan as a biomaterial using light polarization Mueller analytical model which are not well understood by conventional characterization techniques. Despite the physical, mechanical and chemical properties measured by Scanning Electron Microscope (SEM), X-ray Powder Diffraction (XRD) and FTIR (Fourier Transform Infrared) Spectroscopy, optical properties are very useful to investigate the biodegradable Chitosan based scaffolds in tissue engineering. It has been observed from the SEM, XRD, FTIR and polarimetric results (diattenuation, retardance, depolarization, and degree of polarization) that Chitosan has porosity, amorphous, compactable and anisotropic material.

Cryomilling-induced solid dispersion of poor glass forming/poorly water-soluble mefenamic acid with polyvinylpyrrolidone K12

The effect of mechanical impact on the polymorphic transformation of mefenamic acid (MFA) and the formation of a solid dispersion of mefenamic acid, a poor glass forming/poorly-water soluble compound, with polyvinylpyrrolidone (PVP) K12 was investigated. The implication of solid dispersion formation on solubility enhancement of MFA, prepared by cryomilling, was investigated. Solid state characterization was conducted using powder X-ray diffraction (PXRD) and Fourier-transform infrared (FTIR) spectroscopy combined with crystal structure analysis. Apparent solubility of the mixtures in pH 7.4 buffer was measured. A calculation to compare the powder patterns and FTIR spectra of solid dispersions with the corresponding physical mixtures was conducted. Solid state characterization showed that (1) MFA I transformed to MFA II when pure MFA I was cryogenically milled (CM); and (2) MFA forms a solid dispersion when MFA was cryogenically milled with PVP K12. FTIR spectral analysis showed that hydrogen bonding facilitated by mechanical impact played a major role in forming solid dispersions. The apparent solubility of MFA was significantly improved by making a solid dispersion with PVP K12 via cryomilling. This study highlights the importance of cryomilling with a good hydrogen bond forming excipient as a technique to prepare solid dispersion, especially when a compound shows a poor glass forming ability and therefore, is not easy to form amorphous forms by conventional method.

Thermolysis preparation of ZnS nanoparticles from a nano-structure bithiazole zinc(II) coordination compound

Nano-scale and single crystals of a new tris-chelate Zn(II) compound, {[Zn(DADMBTZ)3](SCN)2⋅4H2O}n, (1), {DADMBTZ=2,2′-diamino-5,5′-dimethyl-4,4′-bithiazole} have been synthesized by the reaction of zinc(II) sulfate, ammonium thiocyanate and DADMBTZ using sonochemical and branched tube methods, respectively. The new nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and FT-IR spectroscopy. Compound (1) was structurally characterized by single crystal X-ray diffraction. Compound (1) form a tris-chelate complex with nearly C3 symmetry. The coordination number of zinc atom in the compound is six with coordinated environments of distorted octahedral, ZnN6. In reaction with DADMBTZ, the ligand DADMBTZ acts as bidentate in compound to form five-membered chelate rings with the same internal angles in coordination polyhedron. The crystal packing is mainly stabilized by N–H----N hydrogen bonding interactions. The thermal stability of compound (1) was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). ZnS nanostructures were obtained by direct thermolyses of compound (1) at 400°C under argon atmosphere. The ZnS nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy.

Synthesis and characterization of nano-scale of a new azido Co(II) complex as single and nano-scale crystals: Bithiazole precursor for the preparation of Co3O4 nano-structures

Nano-scale and single crystals of a new azido Co(II) complex, {[Co(DADMBTZ)2(N3)2]⋅0.25CH3OH} (1), {DADMBTZ=2,2′-diamino-5,5′-dimethyl-4,4′-bithiazole} have been synthesized by the reaction of cobalt chloride, sodium azide and DADMBTZ using sonochemical and heat gradient methods, respectively. The new nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and FT-IR spectroscopy. Complex (1) was structurally characterized by single crystal X-ray diffraction. The coordination number of cobalt atom in the compound is six with coordinated environments of distorted octahedral, CoN6. In reaction with DADMBTZ, the ligand DADMBTZ acts as bidentate in complex to form five-membered chelate rings with different internal angles in coordination polyhedron. Two monodentate azido ions occupy the cis position. The crystal packing is mainly stabilized by NH⋯N hydrogen bonding interactions. The thermal stability of compound (1) was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). Co3O4 nanostructures were obtained by direct thermolyses of compound (1) at 450°C under air atmosphere. The Co3O4 nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy.

Crystal chemistry of macfallite: Relationships to sursassite and pumpellyite

The crystal chemistry of macfallite from Keweenaw County, Michigan was studied using electron microprobe, thermogravimetry (TG), differential thermal analysis (DTA), powder Fourier transform infrared (FTIR) spectroscopy, and single-crystal X-ray diffraction methods. The chemical formula derived from the electron-microprobe measurements is (Ca2.03Na0.01)(Sigma 2.04)(Mn2.513+Al0.27Mg0.09Cu0.032+V0.013+)(Sigma 2.91)Si3.05O10.88(OH)(3.12) (Z = 2). An analysis using the intensities of the MnL beta and MnL alpha X-ray lines shows that most Mn is trivalent.The weight loss from TG measurement is 7.7 wt% at 1000 degrees C, most of which is interpreted to be due to the loss of structural OH groups. The crystal structure of macfallite [a = 8.959(3), b = 6.072(2), c = 10.218(4) angstrom, beta = 110.75(3)degrees, space group P2(1)/m], which is isostructural with sursassite, was refined using 1717 unique reflections to R = 4.1%. The site populations at the three independent octahedral sites, Mn1, Mn2, and Mn3, are Mn0.82Al0.06Mg0.09Cu0.03, Mn0.75Al0.25, and Mn0.95Al0.05, respectively. In agreement with a bond-valence analysis, three crystal-chemically different OH groups are located at the O6, O10, and O11 positions. The site O7 is mostly occupied by oxygen, but ininor amounts of hydroxyl may be located there as well. The powder FTIR spectrum in the region of the OH-stretching vibrations is characterized by three strong bands at 3413, 3376, and 3239 cm(-1) and an additional broad absorption band around 2900 cm(-1). The latter results from a relatively strong hydrogen bond, O6-H center dot center dot center dot O11, with a length of similar to 2.63 angstrom. Although there are three main hydroxyl groups occurring in macfallite, the exact number depends on the concentration of trivalent and divalent cations at the Mn1 site. If divalent cations occur at Mn1, a fourth OH group is necessary to maintain charge balance.

Integration of Fe in natural and synthetic Al-pyrophyllites: an infrared spectroscopic study

AbstractNumerous studies focus on the relationships between chemical composition and OH-band positions in the infrared (IR) spectra of micaceous minerals. These studies are based on the coexistence, in dioctahedral micas or smectites, of several cationic pairs around the hydroxyl group which each produce a characteristic band in the IR spectrum. The aim of this work is to obtain the wavenumber values of the IR OH vibration bands of the (Al-Fe3+)-OH and (Fe3+-Fe3+)-OH local cationic environments of ‘pyrophyllite type’ in order to prove, disprove or modify a model of dioctahedral phyllosilicate OH-stretching band decomposition. Natural samples are characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies and electron microprobe; the hydrothermal synthesis products are also analysed by powder XRD and FTIR after inductively coupled plasma measurements to obtain the chemical compositions of starting gel phases. Natural samples contain some impurities which were eliminated after acid treatment; nevertheless, a small Fe content is found in the pyrophyllite structure. The amount of Fe which is incorporated within the pyrophyllite structure is much more important for the synthetic samples than for the natural ones. The IR OH bands were clearly observed in both natural and synthetic pyrophyllites and assigned to hydroxides bonded to (Al-Al), (Al-Fe) and (Fe-Fe) cationic pairs. During this study, three samples were analysed by DTG to check the cis- or trans-vacant character of the layers and to determine the influence of this structural character on the OH-stretching band position in IR spectroscopy.

A further insight into the mechanism of Ag + biosorption by Lactobacillus sp. strain A09

The mechanism of Ag + biosorption by resting cell of Lactobacillus sp. strain A09 has been further investigated at the molecular level using spectroscopic techniques. The values of estimated equilibrium constants, rate constants, half-life periods and apparent enthalpies of the binding reaction were calculated via the determination of Ag + adsorbed by the biomass using atomic absorption spectrophotometry (AAS). The reductive ratio of the Ag + to Ag 0 by the A09 biomass was examined by X-ray photoelectron spectroscopy (XPS). Analysis for sulfur and nitrogen atomic contents in dry powder of the biomass with EA-1110 elemental analysis (EA) showed that amino acid residues retaining the reductive property of Ag + to Ag 0 are very small quantity, whereas glucose content in the hydrolysates of the biomass analyzed by ultraviolet–visible spectrophotometry (UV–vis) indicated that the amount of reducing sugars in the biomass is much larger than 2.71%. The fourier transform infrared (FTIR) spectrophotometry on blank and silver-loaded biomass demonstrated that the chemical functional group such as the free aldehyde group of the hemiacetalic hydroxyl group from reducing sugars, i.e. the hydrolysates of the polysaccharides from the cell wall plays a leading role in serving as the electron donor for reducing the Ag + to Ag 0. This result was further supported by characterizations on the interaction of the Ag + with glucose using X-ray powder diffractometry (XRD) and FTIR spectroscopy.

Prediction of Thickening Times of Oil Field Cements Using Artificial Neural Networks and Fourier Transform Infrared Spectroscopy

Nonlinear statistical models based on artificial neural networks have been constructed to predict the thickening times of class G, class H, and class A oil well cement slurries from physicochemical data on cement powders. These data include chemical composition, particle-size distributions, and Fourier transform infrared (FTIR) spectra. Thickening times can be predicted with mean residual errors of less than ±10% from measurements of major oxide composition, loss on ignition, insoluble residue, the concentrations of the minerals gypsum, bassanite, anhydrite, calcium hydroxide, and calcium carbonate, and particle-size distribution. This error rises to ±13% when particle-size distribution is omitted from the input data. Similar conclusions apply to models that predict thickening times of cement slurries retarded with 0.2 weight percent calcium lignosulfonate. Slurry thickening times can also be predicted from cement powder FTIR spectra alone, with errors in predictions similar to those for models using the full chemical composition and particle-size distribution data. This implies that the FTIR spectrum of a cement is a signature of its slurry performance properties. Additionally, neural networks can be trained to predict the particle-size distributions and mean particle diameters from FTIR spectra. The occupancies of all particle-size fractions can be predicted to within an absolute error of ±1% , approximately twice the expected experimental error on the measurement. However, the model is able to predict general trends in particle-size distributions between cements effectively.

Prediction of thickening times of oil field cements using artificial neural networks and fourier transform infrared spectroscopy

Abstract Nonlinear statistical models based on artificial neural networks have been constructed to predict the thickening times of class G, class H, and class A oil well cement slurries from physicochemical data on cement powders. These data include chemical composition, particle-size distributions, and Fourier transform infrared (FTIR) spectra. Thickening times can be predicted with mean residual errors of less than ±10% from measurements of major oxide composition, loss on ignition, insoluble residue, the concentrations of the minerals gypsum, bassanite, anhydrite, calcium hydroxide, and calcium carbonate, and particle-size distribution. This error rises to ±13% when particle-size distribution is omitted from the input data. Similar conclusions apply to models that predict thickening times of cement slurries retarded with 0.2 weight percent calcium lignosulfonate. Slurry thickening times can also be predicted from cement powder FTIR spectra alone, with errors in predictions similar to those for models using the full chemical composition and particle-size distribution data. This implies that the FTIR spectrum of a cement is a signature of its slurry performance properties. Additionally, neural networks can be trained to predict the particle-size distributions and mean particle diameters from FTIR spectra. The occupancies of all particle-size fractions can be predicted to within an absolute error of ±1% , approximately twice the expected experimental error on the measurement. However, the model is able to predict general trends in particle-size distributions between cements effectively.

Preparation of Piretanide Polymorphs and Their Physicochemical Properties and Dissolution Behaviors.

Piretanide polymorphs were prepared by recrystallization using 27 organic solvents. We identified a new polymorphism, forms A and B, and 6 solvates. They were characterized by X-ray powder diffractometry, differential scanning calorimetry (DSC), thermogravimetry (TG), Fourier-transform infrared (FTIR) spectroscopy, elemental analysis and scanning electron microscopy. After heating, some solvates transformed to the stable form A, and others to form B. X-ray powder diffraction patterns and FTIR spectra of forms A and B were significantly different. However, the X-ray powder diffraction patterns and FTIR spectra of form A and the bulk sample were similar. The DSC curve of form A showed only an endothermic peak at 227°C corresponding to the melting point. The DSC curve of form B showed endothermic and exothermic peaks at 213 and 216°C, respectively, as well as a subsequent endothermic peak at 227°C. The metastable form B transformed to form A. The dissolution profiles of the bulk sample and form B in JP XII, 1st fluid (pH 1.2) at 37°C were measured by means of the dispersed amount. The solubilities of the bulk sample and form B were estimated to be 8.3 and 13.3mg/100ml, respectively.