Transmission FTIR Research Articles

Green manure as part of organic management cycle: Effects on changes in organic matter characteristics across the soil profile

Green manure (GM) cultivation and incorporation (i.e., GM management) may change soil organic matter (SOM) composition and the agroecosystem functioning. However, the understanding of GM effects on SOM composition, specifically in deeper soil layers, is limited. The objectives of this study were to examine the effects of GM management (as part of an organic agriculture practice), following two years of various doses of compost application, on the changes in SOM and water-extractable organic matter (WEOM) compositional characteristics up to a soil depth of 60cm. Soil samples from a two years compost amended field that was subsequently subjected to GM management were taken in four intervals to a depth of 60cm (0–5, 5–15, 15–30 and 30–60cm) and characterized for organic C content and SOM composition, by FT-IR transmission. Characterization of WEOM included excitation-emission matrices (EEMs) of fluorescence, UV absorbance and dissolved organic C (DOC) measurements. The response of SOM and WEOM to GM management resulted in some opposite trends. The SOM became rather aromatic, with aliphatic CH-containing structures contributing to a greater extent to SOM composition at deeper layers following GM management. By contrast, GM management resulted in (i) a substantial increase in dissolved organic C concentration, (ii) WEOM becoming enriched by hydrophilic aliphatic organic compounds, and (iii) aromatic and fluorescent components increasingly being found at deeper soil layers and hydrophilic aliphatic components at the surface soil. Fluorescent portion of WEOM became enriched by relatively less biodegradable and weaker-soil adsorbing humic-like components; this enrichment increased in deeper soil layers. The effects of past compost application rates on the changes in SOM and WEOM characteristics were either non-significant or negative. In the latter case, an increase in application rate decreased the changes in SOM content of hydrophilic groups and in the fractions of fluorescent components in WEOM. Growing and incorporating plant biomass may mask, at least on a short time scale, the effects of earlier compost applications on changes in SOM and WEOM compositional characteristics.

Optical and structural properties of nanostructured copper oxide thin films as solar selective coating prepared by spray pyrolysis method

AbstractCopper (II) oxide thin films were prepared by spray pyrolysis method on soda-lime glass substrates using copper acetate precursor solution. Influence of substrate temperature on structural and optical properties was investigated. Structural analysis of these layers were carried out by X-ray diffraction (XRD). Single phase nature and high crystallinity of CuO nanostructures were observed on XRD patterns. The general appearance of the films was uniform and black in color. FT-IR transmittance spectra confirmed the results from the XRD study. Selective solar absorber coatings of copper oxide (CuO) on stainless steel substrates was prepared by spray pyrolysis method. Effect of deposition temperature on optical properties of thin films was investigated. Optical parameters, absorbance (α) and emittance (α) were evaluated from reflectance data. It can be deduced that the porous structure, such as a light traps, can greatly enhance absorbance, while the composition, thickness and roughness of thin films can greatly influence the emissivity. Single phase nature and high crystallinity of CuO nanostructures were observed by XRD patterns. Solar absorbance of thin films were in the range of 85 % to 92 %.

Synthesis of phytochemicals-stabilized gold nanoparticles and their biological activities against bacteria and Leishmania

Nanoscale materials have shown promising results in the field of medicine as therapeutic agents and drugs delivery vehicles. In the current study, gold nanoparticles (AuNPs) were prepared by a green and facile method using the aqueous extract of Rhazya stricta decne as a source of reducing and stabilizing agents. The bio-fabricated AuNPs were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM) and FTIR spectroscopy. Antimicrobial activities of the biosynthesized AuNPs were tested against Leishmania tropica (HTD7), E. coli and S. aureus. AuNPs were the most effective agents in inhibiting the growth of intra-THP-1 amastigotes at 100 μg/mL concentration (IC50 = 43 μg/mL) after 48-h incubation. In addition, the prepared AuNPs also displayed good activity against E. coli (MIC = 25.0 μg/mL) and Bacillus subtilis (50.0 μg/mL). Interestingly, biogenic AuNPs did not exhibit cytotoxic effect against the THP-1 cells after 24 h exposure. The findings of this study conclude that phytochemicals-stabilized AuNPs could be a safe and effective source of antimicrobial agents.

γ-MnOOH nanorods: Efficient adsorbent for removal of methylene blue from aqueous solutions

Nanostructured metal oxides have been of great interest for the removal of hazardous chemicals and dyes from aqueous media. The present work demonstrates efficient and fast removal of dyes from aqueous solutions by using γ-MnOOH nanorods, which are synthesized by the simple hydrothermal method. Uniformly sized γ-MnOOH nanorods are characterized by using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, FT-IR spectroscopy and BET surface area measurements. Adsorption studies of Methylene blue (MB) dye from aqueous solution onto as-prepared γ-MnOOH nanorods are carried out and the effects of contact time, pH and adsorbent dosage on the dye adsorption have been investigated in detail. Desorption as well as regeneration studies are carried out for probing the possibility of reusing the adsorbent. Equilibrium studies showed that the experimental data fits well with Temkin isotherm. Study of the kinetics showed that the adsorption of MB onto γ-MnOOH nanorods follows pseudo-second-order model. This mesoporous material of average pore diameter of 18nm exhibited excellent sorption properties with a high removal capacity of 89% at 30°C. The thermodynamic parameters have been evaluated from the adsorption experiments.

Facile charge transport in $$\hbox {FeN}_{\mathrm{x}}/\hbox {Mo}_{2}\hbox {N/CNT}$$ FeN x / Mo 2 N/CNT nanocomposites for efficient hydrogen evolution reactions

Molybdenum based materials are gaining importance as electrocatalysts for hydrogen evolution reaction because of their low cost and good electrocatalytic efficiency. Introducing iron nitride with molybdenum nitride as a composite results in efficient hydrogen evolution activity with current density of $${\sim }120$$ $$\hbox {mA/cm}^{2}$$ at $$-400 \hbox { mV}$$ vs. RHE. The nanocomposites were characterized using powder XRD, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Electron Diffraction, Thermogravimetric Analysis and FTIR Spectroscopy. The electrochemical investigations suggest that the electrocatalytic activity of the composite increases with iron nitride content. The composite exhibits good electrochemical stability upto 42 hours in acidic medium. The hydrogen evolution reaction (HER) follows Volmer-Heyrovsky mechanism where Volmer reaction is the rate determing step. SYNOPSIS Introducing iron nitride in composite with molybdenum nitride leads to higher HER activity in acidic media. The in-situ growth of CNTs in the composites enhances the conductivity and decreases the charge transfer resistance.

Structural, dielectric and optical investigation of chemically synthesized Ag-doped ZnO nanoparticles composites

The sol–gel technique was used in the chemical synthesis and characterizations based on structural, morphological, optical and electrical studies of pure and Ag-doped zinc oxide (ZnO) nanoparticles. X-ray diffraction, scanning electron microscopy, energy Dispersive X-ray spectrometry, transmission electron microscope, ultraviolet spectroscopy, photoluminescence and FT-IR analysis were used to perform the characterization of the morphological analysis, optical studies, phase purity and crystalline size. The Powder X-ray diffraction results proved polycrystalline nature of ZnO with a hexagonal wurtzite structure. Debye-Scherrer’s formula was used to evaluate the average crystallite size of pure and Ag-doped ZnO. Their values have been determined to be 14 and 18 nm respectively. To examine the various functional groups FTIR was utilized. The unique aggregation of the particles was stated by the scanning electron microscopy investigation and transmission electron microscope analysis was used to substantiate the nanosphere formation. Here, the estimated optical band gap value for pure and Ag-doped ZnO nanoparticles was 3.22 and 3.17 eV, respectively. UV–visible spectroscopy was used to perform this process. Photoluminescence studies have proved the Ag-doped ZnO sample of the blue shift emission bands. At different frequencies and temperatures, under specific conditions, the dielectric properties like dielectric constant, dielectric loss and AC conductivity of Ag-doped ZnO nanoparticles were analyzed.

Polyhedral oligomeric silsesquioxane-based hybrid networks obtained via thiol-epoxy click chemistry

A series of hybrid networks based on polyhedral oligomeric silsesquioxane (POSS) were prepared by thiol-epoxy click reaction using commercially available octakis-glycidyl-POSS (G-POSS), trimethylolpropane triglycidyl ether, and trimethylolpropane tris(3-mercaptopropionate) as monomers. The click reaction was simply catalyzed by lithium hydroxide which proceeded readily at ambient conditions in very good yields. The incorporation of G-POSS into the network was clearly determined by transmission electron microscopy, FTIR, and 1H-NMR spectroscopy techniques performed with a model study using 1-butane thiol and G-POSS molecules. The homogeneous distribution of G-POSS up to 5 wt% in the hybrid network was apparently confirmed by morphological investigations. By increasing G-POSS content higher than 5 wt%, the heterogeneous dispersion of G-POSS was determined from the tensile strength measurements. The significant decrease in tensile strength was possible due to the agglomeration of G-POSS. On the other hand, thermal properties of hybrid networks were compared together by thermogravimetric analyses, where all samples exhibited one-step degradation in the range of 220–500 °C. The thermal decomposition of hybrid network led to complete degradation of the organic part and favored the formation of stable carbonaceous and inorganic residues as char. Thus, the char yields of hybrid networks were increased to 6.2, 7.8, 10.1, 12.7, and 15.1% by G-POSS loadings from 0 to 15 wt%. This improvement was also a proof of the incorporation of G-POSS into the hybrid networks that resulted in high heat-resistant POSS-based hybrid networks compared to a sample without G-POSS.

Fabrication of nanocrystalline Sc2O3-Y2O3 solid solution ceramics by spark plasma sintering

Abstract Sc 2 O 3 -Y 2 O 3 solid solution (SYSS) ceramics with novel nanocrystalline structures have been successfully fabricated by spark plasma sintering (SPS) method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR and indentation techniques. The SYSS ceramics can possess high hardness by keeping their excellent infrared transmission performance. Especially, the transmittance of as-obtained SYSS ceramics can exceed as high as 80% in the infrared region of 2–6 µm. Moreover, the Vickers hardness is increased to 9.18 GPa by increasing the addition ratio of Sc 2 O 3 to 20 at%. Here, it is very important to point out that the mechanical strength of yttria ceramics can be evidently enhanced without deteriorating their optical transmission performance by the addition of Sc 2 O 3 as well as the application of SPS technique, where the solid solution strengthening and fine grain strengthening are involved during the synthesis process, respectively.

Nanoencapsulation of chia seed oil with chia mucilage (Salvia hispanica L.) as wall material: Characterization and stability evaluation

In this study, chia seed oil was nanoencapsulated utilizing chia seed mucilage (CSM) as wall material. The viscosity, encapsulation efficiency, loading capacity, transmission electron microscopy, FT-IR spectroscopy and thermal properties of chia seed oil nanoparticles (CSO-NP) were performed after preparation. Particle size, zeta potential, span value, and pH of CSO-NP and oxidation stability of nanoencapsulated and unencapsulated oil were evaluated during 28days of storage at accelerated conditions (40°C). The CSO-NP showed spherical shape, an average size of 205±4.24nm and zeta potential of −11.58±1.87mV. The encapsulation efficiency (82.8%), loading capacity (35.38%) and FT-IR spectroscopy demonstrated the interaction between oil and mucilage. Furthermore, CSO-NP were thermally stable at temperatures up 300°C and nanoencapsulated oil showed higher stability against oxidation than unencapsulated oil. The results suggest that chia seed mucilage represents a promising alternative to substitute synthetic polymers in nanoencapsulation.

A nanoscale Cu-metal organic framework with Schiff base ligand: Synthesis, characterization and investigation catalytic activity in the oxidation of alcohols

Nanostructures of a new copper-based metal-organic framework with a Schiff base ligand as an organic linker, Cu2 (bdda) (OAc)2·1H2O (H2bdda=4,4′-[benzene-1,4-diylbis (methylylidenenitrilo)] dibenzoic acid), was prepared via Ultrasound assisted synthesis and characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), inductively coupled plasma atomic emission spectroscopy (ICP-AES), transmission electron microscope (TEM), elemental analysis (CHN) and FT-IR spectroscopy. Catalytic proficiency of this MOF in the oxidation of alcohols was investigated that exhibited efficient and selective activity for the transformation of alcohols to the corresponding carbonyl compounds under the absence of organic solvents. The reusability of the catalyst also was examined, in which the catalyst was reused six times without significant loss of its catalytic efficiency.

Light‐induced electrons suppressed by Eu3+ ions doped in Ca11.94−xSrxAl14O33 caged phosphors for LED and FEDs

AbstractControl of light‐induced electron generation is of vital importance for the application of caged phosphors. For Eu‐doped Ca11.94−xSrxAl14O33 caged phosphors, the suppressed effect of strontium doping on the light‐induced electrons is observed compared to the europium‐free Ca11.94−xSrxAl14O33 phosphors. In the presence of europium ions, Sr doping will promote the reduction of Eu3+ to Eu2+. The Rietveld refinement suggests that unit cell volumes of the Ca11.94−xSrxAl14O33:Eu0.06 samples are expanded when Ca2+ ions are replaced by Sr2+ ions. The absorption and FTIR transmittance spectra confirm that the competitive reaction of encaged O2− anions with H2 is suppressed. For the sample (x=0.48), the higher thermal activation energy (~0.40 eV) for luminescence quenching can be attributed to the more rigid framework structure after Sr doping. For Ca11.94−xSrxAl14O33:Eu0.06 phosphors, their emission colours are tuned from red to purple upon 254 nm excitation and from pink to blue under electron beam excitation through Sr substitution. The insight gained from this work may have a significant guiding to design new phosphors for LED and FEDs and novel nanocaged mutifunctional materials.

Preparation and Characterization of Zirconia Nanomaterial as a Molybdenum-99 Adsorbent

The present study deals with the synthesis and characterization of ZrO 2 nanomaterial which can be used as an adsorbent for Molybdenum-99 ( 99 Mo). The adsorbent can potentially be utilized as the material for 99 Mo/ 99m Tc generator column. Using the sol-gel method, monoclinic nanocrystalline zirconia was synthesized from zirconium oxychloride in isopropyl alcohol reacted with ammonium hydroxide solution in isopropyl alcohol resulting in a white gel. The gel was subsequently refluxed for 12 hours at ~95°C and pH at ~4 and then dried at 100°C. The drying gel was then calcined at 600°C for two hours. Meanwhile the orthorhombic nanocrystalline zirconia was obtained by reacting zirconium oxychloride solution with 2.5 M ammonium hydroxide solution which resulted in a white gel. The gel was then refluxed for 24 hours at ~95°C and pH at ~11 and then dried at 100°C. The drying gel was then calcined at 600°C for two hours. These materials were characterized using FT-IR spectroscopy, X-ray diffraction (XRD), and Transmission Electron Microscope (TEM). The Scherrer method is used for determination of crystallite size. The FT-IR spectra for both materials show absorption peak at 450-500 cm -1 which are attributed to Zr-O bond. The XRD pattern of monoclinic nanocrystalline form shows crystalline peaks at 2θ regions of 28.37°, 31.65°, 34°, 36°, and 50.3° with average crystallite size of 2.68 nm. Meanwhile, the XRD pattern of orthorhombic nanocrystalline form shows crystalline peaks at 2θ regions of 30°, 35°, 50°, and 60° with average crystallite size of 0.98 nm. The TEM micrograph indicates that the zirconia nanomaterials prepared were quite uniform in size and shape. Received: 1 2 November 2015; Revised: 9 Septem ber 2016 ; Accepted: 20 September 2016

Optimizing the synthesis procedure and characterization of terbium(III) tungstate nanoparticles as high performance photocatalysts

Through the application of Taguchi robust design (TRD), the operating parameters influencing the synthesis of terbium(III) tungstate nanoparticles via the chemical precipitation reaction were optimized. The overall reaction involved the direct addition of different aqueous terbium(III) solutions to those of tungstate ion solution, and the statistical approach was used to optimize the effects of the operating parameters on the size of the prepared terbium(III) tungstate particles. To this end, analysis of variance (ANOVA) evaluations were performed to evaluate the importance of the different variables including tungstate and terbium ion concentrations, the flow rate at which the cation was added to the tungstate solution (Fc) and the reaction temperature. After optimizing the synthesis procedure, terbium(III) tungstate nanoparticles were prepared under the optimal conditions, and their morphology and chemical composition were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR spectroscopy, and UV–Vis spectrometry. The optimal product was also evaluated as a photocatalyst in the UV-induced catalytic degradation of methyl orange (MO), and was found to possess an excellent activity for catalyzing this reaction, which can be regarded as an indication for its photocatalytic potentials for other similar reactions.

Investigations of Magnetic Properties of Oleic Acid and Oleyl Amine Capped Nanostructured CoxNi1−x (0.2 ≤ x ≤ 0.8) Alloys

In this study, nanocrystalline oleic acid and oleyl amine capped Co x Ni1−x alloys (x = 0.2, 0.4, 0.6, 0.8) have been synthesized via chemical reduction route. As-prepared as well as annealed samples were characterized using FTIR spectroscopy, X-ray diffraction and transmission electron microscopy. CoNi alloys were found to be capped with oleic acid-oleylamine complex even after heat treatment up to 400 °BC. XRD patterns confirm that the CoNi alloys crystallize in pure fcc phase with average crystallite sizes in the range of 8–11 nm. TEM micrographs confirm nearly spherical morphologies with narrow particle size distribution of the synthesized CoNi alloys. Average TEM particle sizes range from 7 nm to 12 nm. As-prepared as well as annealed CoNi alloys are ferromagnetic in nature at 298 K. M s values for annealed CoNi alloys are found to be in the range of 25–59.6 emu/g after correction for weight fraction of capped matrix and H c values are in the range of 52–314 Oe. Observed magnetic properties have been interpreted on the basis of size effects, altered crystal anisotropies and spin canting on the surface. FC/ZFC magnetization measurements show magnetic irreversibility and superparamagnetic blocking of nanoparticles due to strong dipolar interactions and particle size distribution. A structure-property correlation in CoNi alloys has been attempted in this investigation.

Facile synthesis of bioglass nanospheres for the adsorption of cationic and anionic dyes from aqueous solution

ABSTRACTA novel adsorbent, bioglass nanospheres (BGN), has been prepared by a facile process. The BGN were spheres with an amorphous structure and a relatively high specific surface area, as indicated by SEM, transmission electron microscopy, BET, FTIR, and XRD. This paper was aimed at evaluating the adsorption behavior of this new material for the adsorptive removal of cationic (methylene blue, neutral red) and anionic (congo red) dyes from aqueous solution. The effects of the initial dye concentration, contact time, solution pH, and temperature were investigated. The adsorption kinetics showed that the adsorption behavior followed the pseudo-second-order kinetic model. The adsorption isotherm fit well to the Langmuir model. Thermodynamic analyses showed that the adsorption was physisorption, and it was also a spontaneous and endothermic process. The BGN exhibited a good reusability after five consecutive cycles for cationic dyes. In addition, the possible adsorption mechanism was also proposed based on the above experimental results.

Carbon dots codoped with nitrogen and sulfur are viable fluorescent probes for chromium(VI)

Carbon dots codoped with nitrogen and sulfur (N,S-CDs) were synthesized by a single-step hydrothermal method. The N, S-CDs were characterized by transmission electron microscopy, X-ray diffraction, FTIR and X-ray photoelectron spectroscopy in terms of surface morphology, functional groups and surface composition and elemental composition. The CDs possess intense fluorescence and excitation wavelength dependent emission wavelengths. Fluorescence is strongest at an excitation wavelength of 360 nm and typically peaks at 440 nm. The fluorescence of the N,S-CDs is quenched by Cr(VI) ion. Under the 360 nm excitation wavelength condition, fluorescence intensity decreases linearly on increasing the Cr(VI) concentration from 1 μM to 10 μM, and the LOD at a signal-to-noise ratio of 3 was about 0.2 μM. The method was applied to the quantitation of Cr(VI) in spiked real samples and gave satisfactory results.

Application of the chemiluminescence system composed of silicon-doped carbon dots, iron(II) and K2S2O8 to the determination of norfloxacin

The authors describe a new chemiluminescence (CL) system composed of Si-doped carbon dots (Si-CDs), Fe(II) ions, and K2S2O8. The Si-CDs were prepared by a hydrothermal method and characterized by fluorescence spectra, transmission electron microscopy, energy-dispersive X-ray and FTIR spectroscopy. The weak CL of the Fe(II)-K2S2O8 reaction is found to be intensified by a factor of ~125 in the presence of Si-CDs. The possible mechanism for CL and its enhancement was studied by recording fluorescence and CL spectra and by investigating the effect of some radical scavengers. It is found that norfloxacin exerts a strong enhancing effect on the CL intensity of the system. This finding was employed to design a CL-based norfloxacin assay that works in the 5.0 to 300 μg L−1 concentration range, with a limit of detection (3 σ) of 1.5 μg L−1. The method was applied to the determination of therapeutic levels of norfloxacin in spiked human plasma and gave satisfactory results.

Preparation and application of covalently bonded polysaccharide-modified stationary phase for per aqueous liquid chromatography

The mixed phosphorylated/methacryloyl polysaccharide derivative was prepared and immobilized onto porous silica surface through the radical polymerization. The successful immobilization of polysaccharide on the silica support was confirmed by FT-IR spectra, elemental analysis and transmission electron microscopy (TEM), and so on. The new stationary phase (MCPP-SP) showed both hydrophilic interaction liquid chromatography (HILIC) and per aqueous liquid chromatography (PALC) characteristics. The chromatographic behaviors were evaluated by investigating the effects of water content, column temperature, mobile phase pH and salt concentration, and a typical PALC retention feature of MCPP-SP based column was observed at high percentage of water content. Compared with C18 column, using MCPP-SP column, separation of polar compounds including synthetic pigments and sulfa compounds in the PALC mode was successfully accomplished. The results demonstrated that MCPP-SP column exhibited stronger retention efficiency for various polar compounds. PALC as a green chromatography analytical method was suitable for the replacement of HILIC.

Synthesis and Evaluation of a Triblock Copolymer/ZnO Nanoparticles from Poly(ε-caprolactone) and Poly(Acrylic Acid) as a Potential Drug Delivery Carrier.

Through the present paper, a triblock copolymer containing pH-responsive (polyacrylic acid-b-polycaprolactone -b-polyacrylic acid) (PAA-b-PCL-b-PAA) was synthesized by using the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) and the reversible addition fragmentation chain transfer (RAFT) polymerization of the acrylic acid methods, as the drug carrier. Blends of the nanocrystalline zinc oxide nanoparticles (n-ZnO) and triblock copolymer treated from the solution have been used to make the hybrid polymer-metal oxide for the preparation of the drug loaded nanocomposite. The drug-release behavior of the nanocomposite was studied by using the Doxorubicin as a model drug. In addition to the self-assembly and pH-responsive behavior of the triblock copolymers/ZnO was studied in solution by the Fluorescence Spectroscopy, Scanning Electron Microscopy(SEM), Transmission Electron Microscopy (TEM), DLS, HNMR and FT-IR spectroscopy.

Catalyst Deactivation in Pyridine-Assisted Selective Dehydration of Methyl Lactate on NaY

Acrylic acid is a major commodity chemical currently produced almost entirely from petroleum-derived sources. The catalytic dehydration of methyl lactate is a promising renewable route to producing this vital chemical feedstock; however, enhancing the selectivity toward the dehydration pathway and catalyst stability remain challenging. We demonstrate a selectivity for dehydration products of ∼90% over a period of 30 h on NaY by introducing a small amount of pyridine in the reactant feed (pyridine/methyl lactate = 1:10). This increase in selectivity is attributed to the inhibition of side pathways, i.e., decarbonylation and coking, both of which are catalyzed by surface Bronsted acid sites generated in situ, rather than the acceleration of the dehydration pathway. Catalyst deactivation is shown to proceed through a drastically different mechanism in the absence and presence of pyridine in the feed via a combination of activity tests, thermogravimetric analysis, N2, and transmission FTIR spectroscopic inves...