FTIR Bands Research Articles

Functionalisation of organosolv lignin by enzymatic demethylation for bioadhesive formulation

Bio-based adhesives offer a sustainable alternative to formaldehyde-based adhesives, which is the most common product applied in wood-based panel manufacturing. Despite the undeniable interest in lignin as a bulk chemical for the synthesis of bio-based adhesives, the main problem is its low reactivity. Therefore, it is crucial to study techniques to increase their reactivity, such as demethylation. One of the parameters to monitor the success of the demethylation is the methanol concentration measured in the reaction medium and complementing these results with the use of non-quantitative analyses such as FT-IR, MALDI-ToF and SEC. In order to maximize the action of the enzyme, a preliminary screening was performed with laccases with different redox potentials, which were added to organosolv lignin in the form of purified enzymes and cocktails. Trametes versicolor laccase was selected as the best candidate for the demethylation of organosolv lignin, with a methanol released concentration of 107 mg/L. Based on these results, parameters affecting both enzyme action and enzyme-substrate interaction were evaluated. Optimal working conditions were strongly defined by the use of surfactants that enhanced lignin solubility (Tween-80) and mediators that favored enzyme catalysis to participate directly in the enzyme catalytic cycle (HBT). However, it was also observed that factors such as pH, temperature and aeration have a direct impact on the enzymatic demethylation of lignin. Considering the operational variables that allowed better demethylation values, the amount of methanol released increased to 363 mg/L, which means an improvement of 239 %. These results were also supported by the increase in molecular weight observed in the SEC analysis and the reduction of the intensity of the FT-IR bands related to the methyl/methoxyl groups.

Transferring the wide band gap chitosan: POZ-based polymer blends to small optical energy band gap polymer composites through the inclusion of green synthesized Zn2+-PPL metal complex

In this study, the solution of black tea leaves (BTL) was extracted and used as a green coordination approach to synthesize Zinc metal ions (Zn2+)- polyphenol (PPL) complexes (Zn2+-PPL complexes) with increased UV–vis absorption. The FTIR of the BTL and Zn2+-PPL complex confirms the formation of the Zn2+-PPL complex through the wide variation in the intensity of FTIR bands. XRD shows that the interaction between Zn2+ ions and PPL produced an amorphous Zn2+-PPL complex. The prepared Zn2+-PPL complex with chitosan: Poly(2-ethyl-2-oxazoline) (CS: POZ) polymer blends exhibit enhanced optical properties. The polymer composite (PC) films are synthesized using the solution casting process. FTIR, XRD, and UV–vis spectroscopy techniques approve the synthesis of PCs films with handled optical properties. The structural properties of CS: POZ: Zn2+-PPL complex composite films confirm the amorphous phase dominant. The optical properties of CS: POZ blend and CS: POZ: Zn2+-PPL complex films are determined using UV–Visible spectroscopy, including refractive index (n), absorption edge, dielectric loss (εi), dielectric constant (εr), and bandgap energy (Eg). The Eg is measured by examining the εi optical parameter, whereas the types of electronic transition in the films are detected using Tauc's technique. Significant optical parameters such as localized charge density (N/m*), high-frequency dielectric constant (ε∞), relaxation time (τ), optical mobility (μopt), optical resistivity (ρopt), and plasma angular frequency (ωp) of electrons are measured. The N/m* values are increased from 7.3 × 1055m3/kg to 35.3 × 1055m3/kg by adding Zn2+-complex concentration, resulting in a significant reduction (4.8 eV to 1.6 eV) in the Eg. The Wemple–DiDomenico single oscillator model was used to measure the oscillator dispersion energy (Ed) and average oscillator energy (Eo) property.

ANTIMICROBIAL ACTIVITY, MOLECULAR DOCKING, SPECTROSCOPIC, DFT AND VIBRATIONAL ANALYSIS ON 3-(4 BROMOPHENYL)-1-METHOXY-1-METHYL UREA

The main objective of the study is to analyze the spectral behaviour and antimicrobial activity of 3-(4 bromophenyl)-1- methoxy-1-methyl urea by experiment, theoretical spectroscopic, IR, Raman and UV-Vis techniques. The optimized geometrical parameters were reported on DFT/B3LYP/6-311++G (d, p) basis set of theory. Based on the potential distribution of energy, the detailed vibrational assignments of observed FT-IR and FT-Raman bands have been proposed. The distribution of vibrational modes was carried out by using normal coordinate analysis. Antimicrobial activity of BMM molecule was confirmed using molecular docking analysis. In vitro antimicrobial studies were carried out against the bacterial strains E. coli and Candida sp.

Impact effect of gamma irradiation on the optical, FTIR, ESR spectral properties and thermal behavior of some mixed (PbO + Bi2O3) borate glasses searching for shielding effects

Four borate glasses with mixed and equal heavy metal oxides PbO+Bi2O3 ranging from 70→55% were prepared by routine melting and annealing technique. These glasses were selected to identify the effects of gamma irradiation on glasses combining two heavy metal oxides (PbO, and Bi2O3) which are known to be of shielding nature towards irradiation. Collective measurements of the optical, structural FTIR and ESR. spectral properties of the prepared equal mixed glasses were carried out before and after a relatively high dose of gamma rays (6 M rad). Optical spectra of the glasses reveal before irradiation strong UV absorption due to trace ferric ions present as impurities in the chemicals used for the preparation of the glasses. After irradiation, an extra small induced near-visible band at 420 nm has been identified and is attributed to the creation of an induced boron- oxygen hole center (BOHC) or nonbridging oxygen hole center (NBOHC). FTIR spectra reveal distinct vibrational bands due to triangular (BO3 groups) and tetrahedral (BO4 groups) within their variant characteristic wavenumbers. Also, the condensed intensities of the FTIR bands refer to the sharing of vibrations due to PbO or BiO within their specific sites as evidenced by the deconvoluted spectra. Gamma irradiation causes no variations on the FTIR and ESR spectra confirming the shielding effect of the heavy metal oxides present in mixed percentages.

Iodine Uptake by Zr-/Hf-Based UiO-66 Materials: The Influence of Metal Substitution on Iodine Evolution.

Many works reported the encapsulation of iodine in metal-organic frameworks as well as the I2 → I3- chemical conversion. This transformation has been examined by adsorbing gaseous iodine on a series of UiO-66 materials and the different Hf/Zr metal ratios (0-100% Hf) were evaluated during the evolution of I2 into I3-. The influence of the hafnium content on the UiO-66 structure was highlighted by PXRD, SEM images, and gas sorption tests. The UiO-66(Hf) presented smaller lattice parameter (a = 20.7232 Å), higher crystallite size (0.18 ≤ Φ ≤ 3.33 μm), and smaller SSABET (818 m2·g-1) when compared to its parent UiO-66(Zr) ─ a = 20.7696 Å, 100 ≤ Φ ≤ 250 nm, and SSABET = 1262 m2·g-1. The effect of replacing Zr atoms by Hf in the physical properties of the UiO-66 was deeply evaluated by a spectroscopic study using UV-vis, FTIR, and Raman characterizations. In this case, the Hf presence reduced the band gap of the UiO-66, from 4.07 eV in UiO-66(Zr) to 3.98 eV in UiO-66(Hf). Furthermore, the UiO-66(Hf) showed a blue shift for several FTIR and Raman bands, indicating a stiffening on the implied interatomic bonds when comparing to UiO-66(Zr) spectra. Hafnium was found to clearly favor the capture of iodine [285 g·mol-1, against 230 g·mol-1 for UiO-66(Zr)] and the kinetic evolution of I2 into I3- after 16 h of I2 filtration. Three iodine species were typically identified by Raman spectroscopy and chemometric analysis. These species are as follows: "free" I2 (206 cm-1), "perturbed" I2 (173 cm-1), and I3- (115 and 141 cm-1). It was also verified, by FTIR spectroscopy, that the oxo and hydroxyl groups of the inorganic [M6O4(OH)4] (M = Zr, Hf) cluster were perturbed after the adsorption of I2 into UiO-66(Hf), which was ascribed to the higher acid character of Hf. Finally, with that in mind and considering that the EPR results discard the possibility of a redox phenomenon involving the tetravalent cations (Hf4+ or Zr4+), a mechanism was proposed for the conversion of I2 into I3- in UiO-66─based on an electron donor-acceptor complex between the aromatic ring of the BDC linker and the I2 molecule.

Effects of Autoclaving and Freeze-Drying on Physicochemical Properties of Plectranthus esculentus Starch Derivatives.

The goal of this research was to assess the effects of autoclaving followed by freeze-drying on acetylated xerogel (AXS) and carboxymethylated (CMS) derivatives of Plectranthus esculentus starch as potential vaccine stabilizers. Starch extracted from tubers of P. esculentus were modified by single (carboxymethylation) and dual (acetylation followed by xerogel formation) methods. The derivatives were formulated into vaccine stabilizer suspensions, autoclaved, and freeze-dried without additives or antigen. The derivatives and freeze-dried products were assessed by physical appearance, titration, moisture content (MC), TGA, DSC, XRD, SEM, and FTIR analyses. The degrees of substitution (DS) of the CMS and AXS derivatives were 0.345 and 0.033, respectively. Modification significantly reduced the MC of the derivatives. Freeze-dried AXS (FAXS) had lower MC than freeze-dried CMS (FCMS). The lower degree of hydrophilicity/MC of AXS and FAXS was confirmed by TGA and FTIR band intensities and shifts. Reduction in DSC water desorption/evaporation enthalpies (ΔH) from - 1168.8mJ (NaS) to - 407.48mJ (AXS) confirmed the influence of modification on moisture. FTIR confirmed acetylation and carboxymethylation of the derivatives by the presence of 1702.9cm-1 and 1593cm-1 bands, respectively (FTIR). Increasing concentrations of the derivatives yielded uncollapsed/unshrunken lyophilisates. SEM and XRD showed that modification, autoclaving, and freeze-drying yielded beehive-like microstructures of FCMS and FAXS that were completely amorphous. Processing (autoclaving and freeze-drying), therefore, enhanced the amorphousness of the starch derivatives which is required in vaccine stability during processing and storage. These findings indicate that these starch derivatives have potential as novel vaccine stabilizers.

Extraction of Gelatin From Poultry Byproduct: Influence of Drying Method on Structural, Thermal, Functional, and Rheological Characteristics of the Dried Gelatin Powder.

The poultry processing industrial wastes are rich sources of gelatin protein, which can be utilized for various industrial sectors. The present investigation was conducted to evaluate the effect of freeze-drying (FD) and hot air drying (HAD) on the physicochemical, structural, thermal, and functional characteristics of chicken feet gelatin. The yield (%) of extracted FD and HAD gelatin was 14.7 and 14.5%, respectively. The gelatin samples showed lower percent transmittance in the UV region. The FTIR bands were at 3,410–3,448 cm−1, 1,635 cm−1, 1,527–334 cm−1, and 1,242–871 cm−1 representing amide-A, amide-I, amide-II, and amide-III bands, respectively. The water activity of HAD was higher (0.43) than in FD (0.21) samples and pH were 5.23 and 5.14 for HAD and FD samples, respectively. The flow index (n) of 6.67% gelatin solutions was 0.104 and 0.418 with consistency coefficient (k) of 37.94 and 31.68 for HAD and FD samples, respectively. The HAD sample shows higher gel strength (276 g) than the FD samples (251 g). The foaming capacity (FC) and foaming stability (FS) of FD samples were 81 and 79.44% compared to 62 and 71.28% for HAD, respectively. The emulsion capacity and emulsion stability of HAD gelatin were higher at 53.47 and 52.66% than FD gelatin. The water holding capacity (WHC) and oil binding capacity (OBC) of FD were lower, that is, 14.3 and 5.34 mL/g compared to HAD gelatin having 14.54 and 6.2 mL/g WHC and OBC, respectively. Hence, the present study indicated that gelatin samples can be utilized in various food products for enhancing functionality and can be used for developing edible packaging materials.

Biosynthesis of Iron Oxide Nanoparticles: Physico-Chemical Characterization and Their In Vitro Cytotoxicity on Healthy and Tumorigenic Cell Lines.

Iron oxide nanoparticles were synthesized starting from two aqueous extracts based on Artemisia absinthium L. leaf and stems, employing a simplest, eco-friendliness and low toxicity method—green synthesis. The nanoparticles were characterized by powder X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), X-ray fluorescence analysis (XRF), thermal analysis (TG/DSC), and scanning electron microscopy (SEM). Lack of magnetic properties and the reddish-brown color of all the samples confirms the presence of hematite as majority phase. The FTIR bands located at 435 cm−1 and 590 cm−1, are assigned to Fe-O stretching vibration from hematite, confirming the formation of α-Fe2O3 nanoparticles (NPs). The in vitro screening of the samples revealed that the healthy cell line (HaCaT) presents a good viability (above 80%) after exposure to iron oxide NPs and lack of apoptotic features, while the tumorigenic cell lines manifested a higher sensitivity, especially the melanoma cells (A375) when exposed to concentration of 500 µg/mL iron oxide NPs for 72 h. Moreover, A375 cells elicited significant apoptotic markers under these parameters (concentration of 500 µg/mL iron oxide NPs for a contact time of 72 h).

Evaluation of Structural and Optical Properties of Nanocrystalline Cubic Y2O3 Phase Materials via Combustion Method Using Different Fuels

In this work, we have carried out combustion synthesis of nanocrystalline Y2O3 materials using hexamine, polyethylene glycol(200) (PEG(200)), and ethylene glycol (EG) as fuels. In addition, the impact of mechanical stirring of commercial Y2O3 powder with various dilutions of PEG(200) with distilled water as a solvent was also examined. The as-prepared combustion product of the hexamine is significantly different from other fuels (PEG(200) and EG). The annealed combustion products crystallize in the pure cubic Y2O3 phase. The combustion product of PEG(200) reveals a maximum weight loss of ∼46% at 800 °C in the TG curve. The UV–vis-NIR features of different samples show quite interesting results. The Eg values obtained from the Tauc plots are found in the range of 5.48 to 5.71 eV for the different samples. The observed strong FTIR band at 560 ∼ 415 cm−1is owing to the vibrational Y–O bond in the present series samples. The Raman spectra show the highest intensity peak at wavenumber 374 cm−1is owing to the Fg vibrational mode of the Y2O3phase. Agglomerated nature of nanoparticles is seen in the Y2O3 phase samples obtained from EG and hexamine as fuels. The PEG-derived Y2O3 nanomaterials exhibit rather a high reflectance in the NIR region quite comparable to the NIR tendency of the mechanically stirred Y2O3 samples. Thus, the present processed nanocrystalline Y2O3 materials are efficient for solar reflective pigment application in the NIR industry.

Enhanced optical, magnetic, and photocatalytic activity of Mg2+ substituted NiFe2O4 spinel nanoparticles

Magnesium doped nickel ferrite spinel nanostructured were prepared using a microwave combustion method. The structural characterization by XRD analyses confirmed that undoped NiFe2O4 showed a single phase cubic spinel structure. However, with increasing Mg2+ concentration in the range 0.1 to 0.5 induced the crystallization of secondary α-Fe2O3 phase. The cubic nanostructured exhibited an average crystallite size between 20 and 35 nm. The presence of tensile/compressive strain in Mg2+ doped NiFe2O4 was determined from Williamson–Hall (W–H) method. The appearance of FT-IR bands at around 435, 459, and 581 cm−1, characteristics of spinel cubic and rhombohedral stretching modes. The optical band gap as determined by diffuse reflectance spectroscopy (DRS) decreases with increasing Mg2+ content due to the quantum confinement effect. Surface morphology showed nanosized crystalline grains agglomerated with spherical shapes and energy dispersive X-ray analyses was used to examine the elemental composition of the Mg2+ doped NiFe2O4 spinel nanoparticles and confirmed the presence of nickel, magnesium, iron and oxygen elements. Magnetization–Field (M − H) hysteresis curves revealed the appearance of ferromagnetic behavior at room temperature. The as-fabricated Mg2+ doped NiFe2O4 spinel nanostructures were evaluated for the photocatalytic degradation of rhodamine B under visible light irradiation for atmospheric conditions. When a small amount of H2O2 was added during photocatalysis, indicating the samples possessed photo-Fenton like catalytic activity. This type of spinel nanoparticles behaves as an efficient catalyst with high efficiency around above 99%.

Microencapsulated Red Powders from Cornflower Extract-Spectral (FT-IR and FT-Raman) and Antioxidant Characteristics.

Although the health benefits of cornflower extracts are known, their application in food production has not been widely investigated. This study assessed microencapsulated red powders (RP) prepared from the aqueous extract of blue cornflower petals. Microencapsulation was performed by freeze-drying using various stabilizers, such as maltodextrin, guar gum, and lecithin. The microencapsulated RP were characterized by spectral (FT-IR and FT-Raman), mineral, structural, and antioxidant analyses. The FT-IR and FT-Raman band related to guar gum, lecithin, and maltodextrin dominated over the band characteristic of anthocyanins present in the cornflower petal powders. The main difference observed in the FT-Raman spectra was attributed to a shift of bands which is reflection of appearance of flavium cation forms of anthocyanins. The microencapsulated RP had total phenolic content of 21.6–23.4 mg GAE/g DW and total flavonoid content of 5.0–5.23 mg QE/g. The ABTS radical scavenging activity of the tested powders ranged from 13.8 to 20.2 EC50 mg DW/mL. The reducing antioxidant power (RED) of the powders was estimated at between 31.0 and 38.7 EC50 mg DW/mL, and OH• scavenging activity ranged from 1.9 to 2.6 EC50 mg DW/mL. Microencapsulated cornflower RP can be valuable additives to food such as sweets, jellies, puddings, drinks, or dietary supplements.

Fourier transform infrared spectral features of plant biomass components during cotton organ development and their biological implications

BackgroundThe majority of attenuated total reflection Fourier transform infrared (ATR FT-IR) investigations of cotton are focused on the fiber tissue for biological mechanisms and understanding of fiber development and maturity, but rarely on other cotton biomass components. This work examined in detail the ATR FT-IR spectral features of various cotton tissues/organs at reproductive and maturation stages, analyzed and discussed their biological implications.ResultsThe ATR FT-IR spectra of these tissues/organs were analyzed and compared with the focus on the lower wavenumber fingerprinting range. Six outstanding FT-IR bands at 1 730, 1 620, 1 525, 1 235, 1 050 and 895 cm−1 represented the major C=O stretching, protein Amide I, Amide II, the O–H/N–H deformation, the total C–O–C stretching and the β-glycosidic linkage in celluloses, respectively, and impacted differently between these organs with the two growth stages. Furthermore, the band intensity at 1 620, 1 525, 1 235, and 1 050 cm−1 were exclusively and significantly correlated to the levels of protein (Amide I bond), protein (Amide II bond), cellulose, and hemicellulose, respectively, whereas the band at 1 730 cm−1 was negatively correlated with ash content.ConclusionsThe resulting observations indicated the capability of ATR FT-IR spectroscopy for monitoring changes, transportation, and accumulation of the major chemical components in these tissues over the cotton growth period. In other words, this spectral technology could be an effective tool for physiological, biochemical, and morphological research related to cotton biology and development.

Structural and energy storage behavior of ion conducting biopolymer blend electrolytes based on methylcellulose: Dextran polymers

Biodegradable polymer electrolyte has attracted significant attention from both economic and environmental perspectives. This study reports the preparation and analysis of plasticized methylcellulose (MC)-dextran (DN)-ammonium iodide (NH4I) bio-based polymer electrolytes with high ion transport properties using solution casting method.It was discovered that when the glycerol concentrations increased, the FTIR bands changed and dropped in their intensities, revealing good complexation between electrolyte constituents. The glycerol inclusion improved the ionic conductivity up to (3.24 × 10−4) S/cm, according to impedance spectroscopy (EIS). The EEC simulation has been employed to study the electrolyte circuit components further. Transference number measurement (TNM) was used to calculate both transport ion (tion) and electron (tel) values, which were found to be 0.952 and 0.048, respectively. The most conducting sample was found to be stable up to 2 V. Various techniques, such as cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) were utilized to examine the properties of the assembled EDLC device. At the initial cycle, the designed EDLC had a specific capacitance (Cspe) value of ∼ 44F/g, with an energy density of ∼ 4.9 Wh/kg and a power density of ∼ 500 W/kg.

Optical and Chemical Investigations of PEO Thin Films Incorporated with Curcumin Nanoparticle: Effect of Film Thickness

Using the spin coating technique, polyethylene oxide (PEO)-Curcumin nanocomposite thin films have been deposited on a quartz substrate. The film thickness role on the optical properties was investigated. SEM investigated the morphology of the thin films and revealed that curcumin NPs have a spherical shape with an average size of less than 100 nm. FTIR bands observed at 1023 and 1120 cm–1 correspond to C–O stretching vibration. New bands observed for the thin films at 804, 1237, 1280, and 1340 cm–1 correspond to C–H, C–O, and O-H bending. The thin films’ optical properties with thickness 250, 500, and 750 nm were acquired from transmittance, reflectance, Tauc plot, extinction coefficient, and reflective index. The refractive index obtained from UV-Vis data falls between 1.5 and 2. Bandgap energy obtained for PEO thin film is 4.16 eV, while for both curcumin NPs and PEO-Curcumin nanocomposite thin films, the bandgap energy is 2.49 eV. Our results indicate that the optical absorption coefficient increases with decreasing film thickness. The obtained results are in good agreement with the existing reports.

Antibacterial activity and photocatalytic oxidative performance of zinc oxide nanorods biosynthesized using Aerva lanata leaf extract

A simple biosynthesis process was followed for preparing zinc oxide nanorods (ZnO NRs) using Aerva lanata leaf extract as reducing and structure directing agent. The FE-SEM images displayed presence of ZnO NRs with a mean diameter of ∼100 nm. The EDX spectrum ascertained purity of the ZnO NRs. The UV–Vis spectrum exhibited characteristic absorption band of ZnO NRs and their band gap was found out as 3.24 eV. The XRD pattern indicated wurtzite crystalline structure and hexagonal phase of the ZnO NRs with good crystallinity. The FTIR band noticed at 534.34 cm−1 due to the characteristic stretching of Zn–O bond disclosed purity of the ZnO NRs. The antibacterial activity of the ZnO NRs was assessed against selected Gram-positive and Gram-negative bacteria. Among them, highest antibacterial activity was detected against E. coli (ZOI: 8 mm vs 100 μL ZnO NRs) and S. aureus (ZOI: 7 mm vs 100 μL ZnO NRs). Besides, the ZnO NRs were used as photocatalyst towards oxidation of methylene blue dye under natural sunlight illumination. The rate constant for the ZnO NRs and chemically synthesized ZnO NPs towards photocatalytic oxidation of MB dye was found out as 11.28 and 7.80 × 10−4 s−1, respectively. The thermal stability and photostability of the ZnO NRs were confirmed by thermogravimetric analysis and photocatalytic recycling experiments. The proposed mechanisms for the inferior antibacterial activity and significant photocatalytic performance exhibited by the ZnO NRs are discussed in detail.

Preparation, structural characterization and antioxidant activity of water-soluble polysaccharides and purified fractions from blackened jujube by an activity-oriented approach

This study aimed to investigate the structural features and antioxidant activity in vitro of crude blackened jujube polysaccharides (BJPs) and five purified polysaccharides based on the activity-oriented approach. The crude BJPs exhibited dose-dependent radical scavenging activity and total reducing capacity, and provided excellent protective effects against H2O2-damaged HUVECs via up-regulating mitochondrial membrane potential and down-regulating intracellular reactive oxygen species. After fractionation by column chromatography, the five purified components differed in chemical composition, molecular weight, monosaccharide composition (type and relative proportion) and FTIR band (peak pattern or intensity, especially in the range of 1000.0–1200.0 cm−1), as well as protective effects against H2O2-induced HUVECs. As the most abundant and potent antioxidant component, the backbone of BJP-3 was mainly composed of →4)-α-l-GalpA (1→, →5)-α-l-Araf (1→ residues with two terminals of T-α-l-Araf (1→ and T-β-d-Galp (1→. The above results compared the structural and bioactive properties of different blackened jujube polysaccharides and highlighted their potential as antioxidants for functional foods.

Bulk and surface transformations of Ga2O3 nanoparticle catalysts for propane dehydrogenation induced by a H2 treatment

Three γ/β-Ga2O3 nanoparticle catalysts that differ in the relative ratio of γ-Ga2O3 to β-Ga2O3 were prepared to evaluate the effect of H2 treatment (500 °C, 2 h) on the coordination environment of bulk and surface Ga sites, Lewis acidity and catalytic activity in propane dehydrogenation (PDH). Independent of the H2 treatment, the initial PDH activity of the γ/β-Ga2O3 catalysts increases with the fraction of the β-Ga2O3 phase. This is explained by the presence of weak Lewis acid sites (LAS) in β-Ga2O3 while such sites are absent in γ-Ga2O3. Treatment with H2 increases the catalytic activity of all three γ/β-Ga2O3 catalysts but for different reasons. For catalysts with higher fractions of β-Ga2O3, H2 treatment increases further the relative abundance of weak LAS, likely by generating coordinatively unsaturated Ga sites (such as tricoordinated Ga sites nearby oxygen vacancies). In contrast, H2 treatment of a catalyst containing a predominant fraction of γ-Ga2O3 phase induces disorder in the sub-surface structure of the nanoparticle, that is, it forms gallium and oxygen vacancies in the bulk and favors migration of gallium, and likely also of oxygen, to the surface. This induces a surface reconstruction that notably increases the fraction of strong LAS (and proportionally decreases the fraction of medium LAS), while creating no weak LAS in γ-Ga2O3-H2. Therefore, the increase in the catalytic activity of H2-treated γ-Ga2O3 is explained by the higher density of surface Ga sites in γ-Ga2O3-H2 relative to calcined γ-Ga2O3. H2-treated catalysts that contain a higher relative amount of weak LAS also feature a higher relative abundance of gallium hydride species associated with a low frequency FTIR band at ca. 1931–1939 cm−1, that is, weak LAS likely give weakly-bound hydrides in β-Ga2O3. Our results highlight that weak LAS in unsupported Ga2O3 catalysts are more active in PDH than mild or strong LAS.

Co-precipitation synthesis of BiOI/(BiO)2CO3: Brief characterization and the kinetic study in the photodegradation and mineralization of sulfasalazine

A binary BiOI/(BiO)2CO3 catalyst was prepared via the co-precipitation process as a typical bismuth-based photocatalyst. The XRD data confirmed the tetragonal crystals of BiOI and (BiO)2CO3 had been produced. The crystallite size of BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3 samples were 28.94, 23.24, and 25.11 ​nm (Scherrer formula), and 86.26, 28.28, and 39.60 ​nm (Williamson formula), respectively. FTIR bands for the Bi–O and Bi–I in BiOI, the stretching vibrations bands of the Bi–O, the C–O and CO bonds in (BiO)2CO3 were detected, confirming the formation of the proposed semiconductors. DRS results showed the absorption wavelength edges of 684, 362, and 509 ​nm correspond to the band gap values of 1.81, 3.43, 2.44 ​eV for BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3, respectively. This confirms that the binary catalyst is a visible-light-driven photocatalyst. Some lump and plate-like segments were depicted in the SEM images. About 1% and 5% of a 10 ​ppm SSZ solution were removed by direct photolysis and surface adsorption, while photodegradation by BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3 catalysts removed 62, 75, and 81% SSZ molecules during 30 ​min visible irradiation, confirming the high efficiency of the photocatalysis in SSZ removal by the proposed photocatalyst, especially the binary system. The Hinshelwood formula studied the kinetics of the photodegradation process, and a rate constant of 0.106 min−1 (slope) with a t1/2 value of 7.1 ​min was obtained. When the photodegraded SSZ solutions were subjected to the COD experiment y= −0.085–0.106x, r2=0.9725, and k= 0.106 min−1 (t1/2 ​= ​6.5 ​min) were obtained for the mineralized SSZ molecules.

Rapid synthesis and magnetic property characterization of Mg2+ doped Co3O4 nanostructures

Utilizing combustion method Mg substituted Co3O4 nanoparticles were prepared using the fuel L-alanine. The formation of the cubic spinel structure in the prepared undoped Co3O4 and Mg substituted Co3O4 is assured by X-ray diffraction (XRD) studies. The average crystallite size was observed to lie within 48.6 nm to 17.3 nm. The microstructural analysis shown that the prepared nanoparticles are porous in nature comprising of intragranular pores and melded grains with distinct grain boundaries. The bandgap values were determined using Kubelka–Munk (K–M) technique which was found to fall within 1.87–3.64 eV range. Interestingly, para-/superpara- magnetic characteristics was seen at ±15KOe by the magnetic studies. The FT-IR bands at 662 and 569 cm−1are attributed to the Co–O stretching mode of cubic spinel Co3O4 structure for the prepared samples. .

Modification of silica nanoparticles by 2,4-dihydroxybenzaldehyde and 5-bromosalicylaldehyde as new nanocomposites for efficient removal and preconcentration of Cu(ii) and Cd(ii) ions from water, blood, and fish muscles.

Herein, silica nanoparticles were modified by 2,4-dihydroxybenzaldehyde and 5-bromosalicylaldehyde to produce new nanocomposites which were abbreviated as N1 and N2, respectively. The synthesized nanocomposites were used for efficient removal and preconcentration of Cu(ii) and Cd(ii) ions from water, blood, and fish muscles. FE-SEM, FT-IR, XRD, CHN elemental analysis, and nitrogen gas sorption analyzer were used to characterize the new nanocomposites. The XRD proved that the synthesized oxide is cristobalite with an average crystallite size of 54.80 nm. Due to the formation of the C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> N group, the intensity of the XRD peak at 2θ = 21.9° in the N1 and N2 nanocomposites decreased significantly. The FT-IR bands, which appeared at 1603 and 1629 cm−1 in the N1 and N2 nanocomposites, are attributable to the bending vibration of CN and/or OH, respectively. Also, the FE-SEM analysis shows the morphology of the silica nanoparticles which were identified as spherical and rod-like with slight agglomeration while the N1 and N2 nanocomposites have flaky surfaces due to the formation of CN groups. The maximum Cu(ii) ion adsorption capacities of the N1 and N2 nanocomposites are 64.81 and 40.93 mg g−1, respectively. The maximum Cd(ii) ion adsorption capacities of the N1 and N2 nanocomposites are 27.39 and 26.34 mg g−1, respectively. The adsorption of Cu(ii) or Cd(ii) ions using the synthesized nanocomposites is spontaneous, chemical, exothermic, and well-matched with the Langmuir equilibrium isotherm. The recovery findings demonstrate that the preconcentration process is accurate, adaptable, and resulted in quantitative separation because % Recovery is more than 95%. Furthermore, the % RSD was less than 3.5%, indicating good reproducibility.