Reflectance FTIR Research Articles

Core-shell nanofibers of ZnFe2O4/ZnO for enhanced visible-light photoelectrochemical performance

Recent research places significant importance on the development of innovative nanocomposites for photoelectrochemical applications. This paper presents the fabrication, characterization, and possible photoelectrochemical applications of novel ZnFe2O4/ZnO core-shell nanofibers. These core-shell nanofibers were fabricated through co-axial electrospinning using PVP solutions containing iron and zinc nitrate precursors for the core and shell. The structural and optical properties of ZnFe2O4/ZnO core-shell nanofibers were examined through TEM, SEM, XRD, FTIR, Raman spectroscopy, and diffuse reflectance spectroscopy. This comprehensive analysis unveiled that the development of core and shell characteristics was notably influenced by the interdiffusion of [Fe]/[Zn] during the annealing process. The photoelectrochemical properties of ZnFe2O4/ZnO core-shell nanofibers were assessed through electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and the Mott-Schottky method. These core-shell nanofibers demonstrated a robust electrochemical response to visible light. Photocurrent and photoconversion efficiency of the core-shell nanofibers were calculated and compared with the corresponding values for core-shell nanoparticles. The mechanisms underlying the structural, optical, and photoelectrochemical properties of ZnFe2O4/ZnO core-shell nanofibers were discussed. These advanced nanofibers hold potential applications in photocatalysis, photovoltaics, and energy storage, making this research timely and crucial for advancing sustainable energy technologies and environmental remediation efforts.

Synthesis, Structural and Optical Characterisation of Orthoferrites Rfeo3 (R= Pr,Nd)

Orthorhombic structure of rare earth perovskite type oxide (RFeO3, R =Pr, Nd) nano particles prepared by metathesis method. Powders prepared were characterized by several measurements such as X-ray diffraction, scanning electron microscope, EDX, FTIR, and diffuse reflectance spectroscopy to understand their physio-chemical properties. NdFeo3 and PrFeo3, synthesized metathesis method crystallite size of 61nm and 60.5 nm respectively.

Graphite/carbon-doped TiO2 nanocomposite synthesized by ultrasound for the degradation of diclofenac.

Graphite/C-doped TiO2 nanocomposite was synthesized at room temperature using a simple, impressive, and indirect sonication (20kHz) by the cup horn system. Tetrabutyltitanate as the precursor of titanium and graphite (G) as the carbon source was used in the preparation of nanocomposite as a photocatalyst. The molar ratio of G/TiO2 as a key parameter was investigated in the synthesis of G/C-doped TiO2. The obtained materials were widely characterized using XRD, SEM, TEM, FTIR, XPS, and UV-Vis diffuse reflectance techniques. The UV-Vis diffuse reflectance spectroscopy results showed that the edge of light absorption of nanocomposite was distinctly red-shifted to the visible area via carbon doping. The XPS outcomes acknowledged the existence of the C, Ti, and O in the photocatalyst. The composite showed an enhancement in the dissociation efficiency of photoinduced charge carriers through the doping process. The photocatalytic activity of the synthesized nanocomposite was checked with diclofenac (DCF) as a pharmaceutical contaminant. The results displayed that G/C-doped TiO2 represented better photocatalytic performance for DCF than TiO2. This was due to the excellent crystallization, intense absorption of visible light, and the impressive separation of photoinduced charge carriers. Various active species such as •OH, •O2¯, h+, and H2O2 play a role in the degradation of DFC. Therefore, different scavengers were used and the role of each one in degradation was investigated. According to the obtained results, •O2¯ radical showed a major role in the photocatalytic process. This work not only proposes a deep insight into the photosensitization-like mechanism by using G-based materials but also develops new photocatalysts for the removal of emerging organic pollutants from waters using sunlight as available cheap energy.

Interactions between adsorbed hydrogen and water molecules on a polycrystalline Pt electrode studied by in-situ ATR-FTIR spectroscopy

In order to gain further insight into the interactions between hydrogen adsorbed on platinum and water in an acid electrolyte, in situ infrared spectra were examined in detail. A polycrystalline Pt electrode/sulfuric acid solution interphase was observed by in-situ attenuated total reflectance (ATR) FTIR spectroscopy in the potential region between the double layer and hydrogen evolution by use of the potential difference method. The background potential in the measurements was chosen first at 0.7 V vs. RHE to examine the effect of underpotentially deposited hydrogen (HUPD) adsorption on the interfacial water spectra. Analysis of the spectra revealed two well-defined HOH bending bands, a sharp one at 1620 cm−1 and a broad one at 1700 cm−1. The intensity of the 1620 cm−1 band was found to increase linearly with increasing coverage of HUPD determined by the cyclic voltammogram (CV) corrected for the HER current. This led to an assignment to water molecules co-adsorbed with HUPD with only weak interactions with the latter and between each other. The broad band at 1700 cm−1 was assigned to the HOH bending mode of water associated with hydronium ions. Its intensity was found to increase at lower potentials due to its electrostatic attraction to the increasingly negative surface charge. An intense, broad, negative-going band around 2970 cm−1 was found to develop below 0.4 V, which is assigned to water dimers adsorbed at on-top Pt sites in the double layer potential region and desorbed upon adsorption of HUPD. A new choice of the reference potential at 0.2 V was successful in detecting a distinct OH stretching band around 3580 cm−1, which developed in close correlation with the band assigned to overpotentially deposited hydrogen (HOPD) at ca. 2080 cm−1. The band was assigned to the asymmetric OH stretching mode of water molecules hydrogen-bonded with HOPD. Its band intensity was found to increase linearly with that of HOPD with a slope close to 1.0, which suggests a highly polar nature of the Pt-HOPD bond.

Superparamagnetic Fe3O4/In(OH)3 nanocomposite as a functional photocatalyst for the treatment of dyes and microbes under UVC

We report herein an improved method to produce a superparamagnetic Fe3O4/In(OH)3 nanocomposite (SPIDIN) at 25 °C in water by directly reducing FeCl3 with NaBH4 in the presence of In(OH)3 as heterogeneous seeds and non-toxic polyvinylpyrrolidone (PVP) as surfactant. The incorporation of Fe3O4 nanoparticles served to bestow SPIDIN’s superparamagnetic properties which were confirmed in VSM analyses. Interestingly, the addition of Fe3+ led to the formation of In(OH)3 nanorods rather than the commonly observed nanocubes. In comparison to the In(OH)3 system having a band gap of 5.0 eV, two band gaps were observed for binary nanocomposite SPIDIN with one determined as 5.0 eV and the other as 2.8 eV via the use of Tauc’s plot method. SPIDIN was characterized using a combination of PXRD, FESEM, HRTEM, EDS, Zeta Potential, UV-vis diffuse reflectance spectroscopy and FTIR analyses. Under UVC illumination, SPIDIN dispersed on carbon allowed synergistic photodegradation of methylene blue up to 95% within 1 hr. In the presence of H2O2, free standing SPIDIN was able to disinfect Gram-positive Staphylococcus aureus and Gram-negative Salmonella enterica, signifying the potential of SPIDIN in biomedical waste treatment with H2O being the innocuous byproduct.

An organic-organometallic CO-releasing material comprising 4,4'-bipyridine and molybdenum subcarbonyl building blocks.

Over the past two decades, following the discovery of the important biological roles of carbon monoxide (CO), metal carbonyl complexes have been intensively studied as CO-releasing molecules (CORMs) for therapeutic applications. To improve the properties of "bare" low molecular weight CORMs, attention has been drawn to conjugating CORMs with macromolecular and inorganic scaffolds to produce CO-releasing materials (CORMAs) capable of storing and delivering large payloads of the gasotransmitter. A significant obstacle is to obtain CORMAs that retain the beneficial features of the parent CORMs. In the present work, a crystalline metal-organic framework (MOF) formulated as Mo(CO)3(4,4'-bipyridine)3/2 (Mobpy), with a structure based on Mo(CO)3 metallic nodes and bipyridine linkers, has been prepared in near quantitative yield by a straightforward reflux method, and found to exhibit CO-release properties that mimic those typically observed for molybdenum carbonyl CORMs. Mobpy was characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), FT-IR, FT-Raman and diffuse reflectance (DR) UV-vis spectroscopies, and 13C{1H} cross-polarization (CP) magic-angle spinning (MAS) NMR. The release of CO from Mobpy was studied by the deoxy-myoglobin (deoxy-Mb)/carbonmonoxy-myoglobin (MbCO) UV-vis assay. Mobpy liberates CO upon contact with a physiological buffer in the dark, leading to a maximum released amount of 1.3-1.5 mmol g-1, after 1.5 h at 37 °C, with half-lives of 0.5-1.0 h (time to transfer 0.5 equiv. of CO to Mb). In the solid-state and under open air, Mobpy undergoes complete decarbonylation over a period of 42 days, corresponding to a theoretical CO-release of 7.25 mmol g-1.

Analysis of protein-protein and protein-membrane interactions by isotope-edited infrared spectroscopy.

The objective of this work is to highlight the power of isotope-edited Fourier transform infrared (FTIR) spectroscopy in resolving important problems encountered in biochemistry, biophysics, and biomedical research, focusing on protein-protein and protein membrane interactions that play key roles in practically all life processes. An overview of the effects of isotope substitutions in (bio)molecules on spectral frequencies and intensities is given. Data are presented demonstrating how isotope-labeled proteins and/or lipids can be used to elucidate enzymatic mechanisms, the mode of membrane binding of peripheral proteins, regulation of membrane protein function, protein aggregation, and local and global structural changes in proteins during functional transitions. The use of polarized attenuated total reflection FTIR spectroscopy to identify the spatial orientation and the secondary structure of a membrane-bound interfacial enzyme and the mode of lipid hydrolysis is described. Methods of production of site-directed, segmental, and domain-specific labeling of proteins by the synthetic, semisynthetic, and recombinant strategies, including advanced protein engineering technologies such as nonsense suppression and frameshift quadruplet codons are overviewed.

Serum-based ATR-FTIR spectroscopy combined with multivariate analysis for the diagnosis of pre-diabetes and diabetes.

Diabetes mellitus (DM) is a metabolic disease with an increasing prevalence that is causing worldwide concern. The pre-diabetes stage is the only reversible stage in the patho-physiological process towards DM. Due to the limitations of traditional methods, the diagnosis and detection of DM and pre-diabetes are complicated, expensive, and time-consuming. Therefore, it would be of great benefit to develop a simple, rapid and inexpensive diagnostic test. Herein, the infrared (IR) spectra of serum samples from 111 DM patients, 111 pre-diabetes patients and 333 healthy volunteers were collected using attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy and this was combined with the multivariate analysis of principal component analysis linear discriminant analysis (PCA-LDA) to develop a discriminant model to verify the diagnostic potential of this approach. The study found that the accuracy of the test model established by ATR-FTIR spectroscopy combined with PCA-LDA was 97%, and the sensitivity and specificity were 100% and 100% in the control group, 94% and 98% in the pre-diabetes group, and 91% and 98% in the DM group, respectively. This indicates that this method can effectively diagnose DM and pre-diabetes, which has far-reaching clinical significance.

Infrared Spectroscopy Study of Edge Water Penetration at Hydrophilic Bonding Interface

Hydrophilic wafer bonding is a process used to bond two wafers without adding material between the two surfaces. Water has a definite impact both during the bonding (bonding wave propagation, adhesion) (1) and after annealing (mechanical strength of the bonding interface, adherence) (2) during such a process. To have a better understanding of mechanisms ruling direct hydrophilic wafer bonding, it is thus important to quantify the amount of water present at the bonding interface.It is known that water is able to penetrate at the bonding interface at room temperature and 40% relative humidity. This has been demonstrated by analyzing defects with scanning acoustic microscopy (SAM) and from X-Ray Reflectivity (XRR) measurements (3,4). Kinetics observed by Tedjini et al. were consistent with a Lucas-Washburn flow through a one nm gap driven by the capillary forces of the hydrophilic surfaces.Nevertheless, no investigation of this phenomenon was performed using Fourier Transform Infra-Red Multiple Internal Reflection (FTIR-MIR) spectroscopy (5). Infrared spectroscopy of silanols, hydrogen bonded water and free water is well documented (6–8) and provides knowledge about water content and organization at the bonding interface. Here FTIR-MIR spectroscopy yields a direct measurement of the relative amount of water and its structure at the interface.More precisely this study will enable us to compare Si-Si, Si-SiO2 and SiO2-SiO2 water penetration kinetics at a fixed distance from the edge of the bonded substrates. A schematic view of the FTIR-MIR setup is shown in Figure 1 to explain the measurement principle.We report the study of water kinetics penetration at bonding interface by FTIR-MIR characterization. A Gaussian decomposition of the OH stretching absorption band signal allows identifying the contributions of silanols, surface bonded water and free liquid water as shown on Figure 2. The integral of each Gaussian peak is otherwise proportional to the relative amount of water. Surface preparation will be discussed and results compared to other characterizations techniques.REFERENCES Larrey V, Mauguen G, Fournel F, Radisson D, Rieutord F, Morales C, et al. Adhesion Energy and Bonding Wave Velocity Measurements. ECS Transactions. 23 sept 2016;75(9):145-52.Fournel F, Tedjini M, Larrey V, Rieutord F, Morales C, Bridoux C, et al. Impact of Water Edge Absorption on Silicon Oxide Direct Bonding Energy. ECS Transactions. 23 sept 2016;75(9):129-34.Tedjini M, Fournel F, Moriceau H, Larrey V, Landru D, Kononchuk O, et al. Interface water diffusion in silicon direct bonding. Appl Phys Lett. 12 sept 2016;109(11):111603.Rieutord F, Tardif S, Landru D, Kononchuk O, Larrey V, Moriceau H, et al. Edge Water Penetration in Direct Bonding Interface. ECS Trans. 24 août 2016;75(9):163-7.Rochat N, Olivier M, Chabli A, Conne F, Lefeuvre G, Boll-Burdet C. Multiple internal reflection infrared spectroscopy using two-prism coupling geometry: A convenient way for quantitative study of organic contamination on silicon wafers. Appl Phys Lett. 2 oct 2000;77(14):2249-51.Baum M, Rébiscoul D, Juranyi F, Rieutord F. Structural and Dynamical Properties of Water Confined in Highly Ordered Mesoporous Silica in the Presence of Electrolytes. J Phys Chem C. 30 août 2018;122(34):19857-68.Caër SL, Pin S, Esnouf S, Raffy Q, Ph. Renault J, Brubach JB, et al. A trapped water network in nanoporous material: the role of interfaces. Physical Chemistry Chemical Physics. 2011;13(39):17658-66.Davis KM, Tomozawa M. An infrared spectroscopic study of water-related species in silica glasses. Journal of Non-Crystalline Solids. 2 juin 1996;201(3):177-98. Figure 1

Growth Stimulation of Durum Wheat and Common Buckwheat by Non-Thermal Atmospheric Pressure Plasma.

The grains of durum wheat (Triticum durum Desf.) and achenes of common buckwheat (Fagopyrum esculentum Moench) were tested after treatment with two sources of non-thermal atmospheric pressure plasma (DCSBD, MSDBD) with different treatment times (0, 3, 5, 10, 20, 30, and 40 s). The effect of these treatments was monitored with regard to the seed surface diagnostics (water contact angle-WCA, chemical changes by Fourier transform infrared spectroscopy-FTIR); twenty parameters associated with germination and initial seed growth were monitored. A study of the wettability confirmed a decrease in WCA values indicating an increase in surface energy and hydrophilicity depending on the type of seed, plasma source, and treatment time. Surface analysis by attenuated total reflectance FTIR (ATR-FTIR) showed no obvious changes in the chemical bonds on the surface of the plasma-treated seeds, which confirms the non-destructive effect of the plasma on the chemical composition of the seed shell. A multivariate analysis of the data showed many positive trends (not statistically significant) in germination and initial growth parameters. The repeated results for germination rate and root/shoot dry matter ratio indicate the tendency of plants to invest in underground organs. Durum wheat required longer treatment times with non-thermal plasma (10 s, 20 s) for germination and early growth, whereas buckwheat required shorter times (5 s, 10 s). The responses of durum wheat grains to the two non-thermal plasma sources used were equal. In contrast, the responses of buckwheat achenes were more favorable to MSDBD treatment than to DCSBD.

Distinguishable photocatalytic activity of nano polyaniline with quantum dots metal oxide as photocatalysts for photodegradation of Dianix blue dye and different industrial pollutants

Nanopolyaniline (PAN) polymers have recently been under active investigation as promising photocatalysts. In this work, a simple modified sol–gel method is used to make nano PAN polymers, and a chemical polymerization method is used to make nano polyaniline titanium dioxide quantum dots (PAN-TiQD) polymers as an active photocatalyst during the photodegradation of Dianix blue dye as an organic pollutant under xenon light. The traditional colloidal sol–gel method and the microwave-assisted hydrothermal method were used to make TiQD, which was then mixed with nanoPAN to make PAN-5 % TiQD (W/W) nanocomposites. Characterizations like XRD, FTIR, UV and visible diffuse reflectance spectra, TGA, surface area, EDX, and TEM were used to characterize the nanoPAN and PAN-TiQD that were made. Also, the photocatalytic activity of all synthesized polymers was investigated by the photodegradation process of Dianix blue dye as an organic hazardous pollutant in aqueous medium using a xenon photoreactor with an initial power of 75 W/Cm2. The effects of irradiation time and photocatalyst type on the photodegradation process efficiency of Dianix blue dye were examined. After 3 h of photodegradation processes, the photodegradation efficiency of PAN-TiQD reached 69 % compared to 36 % of nanoPAN due to the fact that it contains 5 % TiQD as a highly active catalyst, which reached 91 %. As an added value for this study, a significant contribution is the examination of eight hazardous industrial wastewater samples, which were assessed under direct sunlight and were in accordance with the KSA environmental permissible limit of 1000 ppm.Finally, the recycling processes in the presence of all synthesized catalysts were investigated and evaluated six times. The photodegradation rate of the recycling processes of Dianix blue dye was highly decreased in the presence of nano PAN than PAN-TiQD, while it had a low decreasing percentage in the case of TiQD. The recycling process using sunlight for industrial pollution samples was investigated at one of the KSA textile plants by using six synthetic catalysts and assessing COD and TOC values.

Microplastics absent from reef fish in the Marshall Islands: Multistage screening methods reduced false positives

Island communities, like the Republic of the Marshall Islands (RMI), depend on marine resources for food and economics, so plastic ingestion by those resources is a concern. The gastrointestinal tracts of nine species of reef fish across five trophic groups (97 fish) were examined for plastics >1 mm. Over 2100 putative plastic particles from 72 fish were identified under light microscopy. Only 115 of these from 47 fish passed a plastic screening method using Fourier-transform infrared microspectroscopy (μFTIR) in reflectance mode. All of these were identified as natural materials in a final confirmatory analysis, attenuated total reflectance FTIR. The high false-positive rate of visual and μFTIR methods highlight the importance of using multiple polymer identification methods. Limited studies on ingested plastic in reef fish present challenging comparisons because of different methods used. No plastic >1 mm were found in the RMI reef fish, reassuring human consumers.

Promising Larvicidal Effects of Nanoliposomes Containing Carvone and Mentha spicata and Tanacetum balsamita Essential Oils Against Anopheles stephensi.

The use of synthetic pesticides to control the spread of mosquito-borne diseases has causedenvironmental pollution and insecticide resistance in mosquitoes. Developments of new green insecticides havethus received more attention to overcome these problems. Nanoliposomes containing carvone and essential oils were first prepared. The nanoliposomephysicochemical characteristics (particle size, morphology, and successful loading) were then evaluated byDynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and the Attenuated Total Reflection-Fourier Transform InfraRed (ATR-FTIR) analyses. Larvicidal effects of carvone, Mentha spicata, and Tanacetumbalsamita essential oils were investigated against the main malaria vector, Anopheles stephensi, in non-formulatedand nanoformulated states. The larvicidal effects of nanoformulated states were significantly more potent (7.2 folds, 3.5 folds, and 8folds) than non-formulated states. Nanoliposomes containing M. spicata and T. balsamita essential oils with particlesizes of 175 ± 8 and 184 ± 5 nm showed the best efficacies (LC50 values = 9.74 and 9.36 μg/mL). The prepared samples could be used as new green potent larvicides against An stephensi mosquito infurther field trials. It is also recommended to investigate their efficacies against other mosquitoes.

Strong adhesion using a simple dopamine-based homopolymer

The underwater adhesive materials inspired by marine mussels have been a research hotspot. As is known to all, interface adhesion properties, mechanical properties, rapid response properties are important indicators for the application of underwater adhesive materials. In this study, we report that Poly(N-(3,4-Dihydroxyphenethyl) methacrylamide) (PDMA), a simple dopamine-based homopolymer, replaces complex binary or multiple copolymers as an underwater adhesive material. The influence factors of PDMA were investigated by universal tensile dynamometer, water contact angle tester, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared reflection (FTIR). Meanwhile, the underwater self-assembly performance of PDMA was performed. Compared with the air group, there are more phenolic hydroxyl groups on the surface of the adhesive in the underwater group, and the adhesive performance is better. In summary, PDMA can be regarded as an alternative substitution material for underwater adhesives.

Utilizing Drug Amorphous Solid Dispersions for the Preparation of Dronedarone per os Formulations

Dronedarone (DRN), an antiarrhythmic drug, exhibits potent pharmacological effects in the management of cardiac arrhythmias. Despite its therapeutic potential, DRN faces formulation challenges due to its low aqueous solubility. Hence, the present study is dedicated to the examination of amorphous solid dispersions (ASDs) as a strategic approach for enhancing the solubility of DRN. Initially, the glass forming ability (GFA) of API was assessed alongside its thermal degradation profile, and it was revealed that DRN is a stable glass former (GFA III compound) that remains thermally stable up to approximately 200 °C. Subsequently, five commonly used ASD matrix/carriers, i.e., hydroxypropyl methylcellulose (HPMC), povidone (PVP), copovidone (PVP/VA), Soluplus® (SOL), and Eudragit® E PO (EPO), were screened for the formation of a DRN-based ASD using film casting and solvent shift methods, along with miscibility evaluation measurements. SOL proved to be the most promising matrix/carrier among the others, and, hence, was used to prepare DRN ASDs via the melt-quench method. The physicochemical characterization of the prepared systems (via pXRD) revealed the complete amorphization of the API within the matrix/carrier, while the system was physically stable for at least three months after its preparation. In vitro release studies for the ASDs, conducted under non-sink conditions, revealed the sustained supersaturation of the drug for at least 8 h. Finally, the use of attenuated total reflectance (ATR) FTIR spectroscopy showed the formation of a strong molecular interaction between the drug molecules and SOL.

Lattice-Strained Metallic Aerogels as Efficient and Anti-Poisoning Electrocatalysts for Oxygen Reduction Reaction.

Lattice strain engineering optimizes the interaction between the catalytic surface and adsorbed molecules. This is done by adjusting the electron and geometric structure of the metal site to achieve high electrochemical performance, but, to date, it has been rarely reported on anti-poisoned oxygen reduction reaction (ORR). Herein, lattice-strained Pd@PdBiCo quasi core-shell metallic aerogels (MAs) were designed by "one-pot and two-step" method for anti-poisoned ORR. Pd@PdBiCo MAs/C maintain their original activity (1.034 A mgPd -1 ) in electrolytes with CH3 OH and CO at 0.85 V vs. reversible hydrogen electrode (RHE), outperforming the commercial Pd/C (0.156 A mgPd -1 ), Pd MAs/C (0.351 A mgPd -1 ), and PdBiCo MAs/C (0.227 A mgPd -1 ). Moreover, Pd@PdBiCo MAs/C also show high stability and anti-poisoning with negligible activity decay after 8000 cycles in 0.1 m KOH+0.3 m CH3 OH. These results of X-ray photoelectron spectroscopy, CO stripping, and diffuses reflectance FTIR spectroscopy reveal that the tensile strain and strong interaction between different elements of Pd@PdBiCo MAs/C effectively optimize the electronic structure to promote O2 adsorption and activation, while suppressing CH3 OH oxidation and CO adsorption, leading to high ORR activity and anti-poisoning property. This work inspires the rational design of MAs in fuel cells and beyond.

Rapid Estimation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Composition Using ATR-FTIR.

A great research effort is involved in polyhydroxyalkanoates (PHAs) production and characterization since they are an attractive degradable polyester family that potentially could substitute oil-based polymers. This is due to two main key factors: their production is sustainable, being that they are produced by microorganisms possibly fed by organic waste-derived products, and they are degradable. Moreover, PHAs' thermal and mechanical properties could be tuned by varying their monomeric composition through the proper selection of microorganism feedstock and bioreactor operative conditions. Hence, a rapid and facile determination of the PHA chemical structure by widely available instrumentation is useful. As an alternative to the standard gas-chromatographic method, a new procedure for the composition determination of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P3HBV), the most common PHA copolymer, by attenuated total reflection FTIR (ATR-FTIR) is presented. It is based on the linear dependence of selected and normalized absorption band intensity with the molar fraction of repeating units. To break free from the crystallinity variability, which affects the result reproducibility and data scattering, the polymer sample was rapidly quenched from the melt directly on the surface of the ATR internal reflection element and analyzed. The data obtained from 14 samples with a molar fraction of 3-hydroxybutyrate repeating units (X3HB) ranging from 0.15 to 1 were analyzed. According to preliminary analyses, the normalized intensity of two absorption bands was selected to develop a calibration method able to predict X3HB of unknown samples and to evaluate the related uncertainty through prediction intervals of inverse regression. The proposed method proves to be useful for an easy and rapid estimation of P3HBV composition.

Influence of castor oil-based bio-oil on the properties and microstructure of asphalt binder

This study intends to investigate the influence of castor oil-based bio-oil on the properties and microstructure of asphalt binder. Castor oil-based bio-asphalt (COBA) were prepared by mixing 0%, 5%, 10%, and 15% bio-oil with petroleum asphalt. Their conventional performance was evaluated based on three indexes, including penetration, ductility and softening point. The high- and low-temperature properties of COBA were obtained by dynamic shear rheometer (DSR) and bending beam rheometer (BBR), and the thermostability was analyzed by thermogravimetry (TG). Meanwhile, the moisture-induced shear-thinning index (MISTI) was tested to evaluate the resistance to moisture damage of COBA. Furthermore, the change of microstructure of asphalt modified by bio-oil was revealed by fourier transform infrared reflection (FTIR). The results showed that castor oil-based bio-oil could soften asphalt and reduce its consistency. As the bio-oil was added, the high-temperature performance of COBA was weakened to some extent by decreasing of complex modulus (G*) and rutting factor (G*/sinδ). The thermostability of COBA was slightly higher than that of matrix asphalt, but it would decrease with the addition of bio-oil. Under the same temperature, the ductibility and m value of bio-asphalt increased with added bio-oil, which change trend was opposite for S value and k value. It indicated that the bio-oil increased the low-temperature flexibility and ductibility of petroleum asphalt. MISTI showed that COBA had better resistance to moisture damage than matrix asphalt. FTIR identified castor oil-based bio-oil as a compound mainly composed of light components, and it is mainly physically blended with petroleum asphalt. Also, the amount of acidic compounds in COBA increased with the increase of bio-oil content. Under the impact of the amide groups in bio-oil, the π-π interaction between the asphaltene stacks of COBA changes, resulting in the change of asphaltene clusters. As a result, the bio-oil enhances the liquidity and improves the low-temperature performance. In terms of high-, low-temperature performance and moisture susceptibility, the COBA containing 5% bio-oil was recommended for the construction of traffic infrastructures.

Infrared Spectroscopy Study of Edge Water Penetration at Hydrophilic Bonding Interface

In this article, we report on the use of a new characterization technique to measure the water penetration at the bonding interfaces and to quantify it. This complements previous studies done using X-ray reflectometry and surface acoustic microscopy: Fourier Transform Infra-Red Multiple Internal Reflection (FTIR-MIR) spectroscopy is used here to characterize the evolutions of contributions of silanols, surface bonded water and free liquid water groups.

Silver phosphate–bacterial cellulose nanocomposites as visible light photocatalyst for wastewater purification

Silver phosphate (Ag3PO4) nanoparticles were deposited on bacterial cellulose (BC) nanofibrils as an eco-friendly, efficient, and reusable visible light active photocatalyst. BC–Ag3PO4 nanocomposites (BCAgP) with different BC/Ag3PO4 weight ratios were prepared by solution-precipitation method. The nanocomposites were characterized by UV-Visible diffuse reflection spectroscopy, XRD, FTIR, BET, and FESEM. Highly crystalline Ag3PO4 nanoparticles were well entrapped inside nano fibrillated BC matrix and eventually deposited along the fibers. Photocatalytic activity of the BCAgP nanocomposites were investigated by dye degradation experiments under solar light. The composite with BC: Ag3PO4 weight ratio of 1:4 (BCAgP14) showed the highest photocatalytic efficiency compared to other weight ratios and pure Ag3PO4. The sample also shows good photocatalytic activity even after 4 runs indicating its photostability. Higher photocatalytic efficiency of BCAgP14 nanocomposite was explained due to optimum Ag3PO4 loading and higher visible light absorption capacity. Bacterial cellulose is supposed to improve the photocatalytic activity of silver phosphate by promoting the adsorption of dyes and extending the charge recombination time under visible light of Ag3PO4 photocatalyst.