Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy Research Articles

Impact of Ultrasonic-Assisted Preparation of Water Caltrop Starch–Lipid Complex: Structural and Physicochemical Properties

This study investigates the effect of ultrasonic-assisted preparation on the structural and physicochemical properties of water caltrop starch-palmitic acid complexes as a function of ultrasound intensity and treatment time. All samples exhibited the characteristic birefringence of starch-lipid complexes under the polarized microscope, and flake-like and irregular structure under scanning electron microscope (SEM), indicating the formation of complexes through ultrasonic-assisted preparation. X-ray diffraction pattern further confirmed the transition from the original A-type structure for native starch to V-type structure for starch-lipid complexes, and the relative crystallinity of starch-lipid complexes increased as the ultrasound intensity and treatment time increased. Attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR) analysis indicated a decreasing trend in absorbance ratio at wavenumber of 1022 cm−1/995 cm−1, suggesting that the increase in the complex promoted the self-assembly within the short-range ordered structure, leading to the formation of bonds between the complexes. However, rapid-visco analysis (RVA) demonstrated that the viscosity generally decreased as the ultrasound intensity and treatment time increased, possibly due to the reduction in molecular weight by ultrasound. Differential scanning calorimetric (DSC) analysis revealed that the control starch-lipid complex without ultrasound treatment (US-0-0) exhibited two distinct endothermic peaks above 90 °C, representing Type I (95–105 °C) and Type II (110–120 °C) V-type complexes. However, ultrasound-treated samples showed only one peak around 95–105 °C and increased enthalpy (∆H), which was likely due to the breakdown of amylose and amylopectin, leading to more complex formation with palmitic acid, while the resulting shorter chains in the ultrasound-modified sample favor the formation of Type I complexes.

First report on the structural and functional aspects of androconial gland in Galleria mellonella and Achroia grisella

Aim: This research aims to provide the first comprehensive analysis of the anatomical and functional characteristics of the androconial glands in the Greater wax moth (Galleria mellonella L.) and the Lesser wax oth (Achroia grisella F.). The study seeks to investigate the morphology, dimensions, and chemical composition of androconial glands in these two Lepidoptera species. Methodology: A range of analytical techniques was employed, including Stereomicroscopy, Scanning Electron Microscopy (SEM), Attenuated Total Reflectance-Fourier Transform Infrared Spectrometry (ATR-FTIR), and Gas Chromatography-Mass Spectrometry (GC-MS). Results: Stereomicroscopy and SEM revealed the presence of an oval, bulb-shaped pheromonal glands on the mesowing of both species. Dimensional analysis showed that the and roconial gland in G. mellonella was 1.33 μm long and 4.74 μm wide, while in A. grisella it ranged from 1.23 to 2.33 μm. FT-IR analysis of the wings identified characteristic peaks at 1538.30, 1645.25, 2284.44, 2923.51 and 3275.28 cm-1, corresponding to the presence of alkanes, alcohols and carboxylic acids. GC-MS analysis identified two previously unreported compounds in male G. mellonella: heptadecane and heneicosane. Additionally, cis-9-hexadecenal was identified as a novel compound in male A. grisella. Interpretation: The findings of this study, provides valuable insights into managing wax moth infestations through pheromone-based strategies. Male wax moth pheromones can be effectively utilized as a tool, offering a sustainable and eco-friendly alternative to chemical pesticides. Key words: Androconial gland, Achroia grisella, Galleria mellonella, Lepidoptera, Pheromone

Extraction, Characterization and Antibacterial Activity of Chitosan from Mud Crab Scylla serrata

The shellfish waste accumulated on a huge scale at seashores and in the seafood industry and very low quantities were used to extract chitosan. In this study, chitosan was extracted from the mud crab Scylla serrata shell using conventional chemical methods. The extracted chitosan and commercial chitosan were verified through Field Emission Scanning Electron Microscopy (FE-SEM), Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and an elemental analyzer. ATR-FTIR spectrum confirmed the presence of characteristics compounds of chitosan and XRD patterns exhibited crystallinity of chitosan having centered peaks at 10º and 20º in 2θ. Moreover, 46.24% of the degree of deacetylation was obtained for the extracted chitosan altogether enhancing the quality of extracted chitosan. In addition to this, the extracted chitosan was tested for its antibacterial activity against two Gram-negative (E. coli and Pseudomonas) and two Gram-positive bacteria (Staphylococcus and Bacillus) in vitro. The antimicrobial activity of extracted chitosan was evident with the greater zone of inhibition against E. coli (26±0.32mm) and the least against Staphylococcus (18mm). Hence the present study gives insight into the biological properties of extracted chitosan from Scylla serrata thereby paving the way for its further use in biomedical science and microbiology.

Technical examination of Wat Sisowath Ratanaram panel painting

The technical examination on the early 20th century panel painting of Wat Sisowath Ratanaram was performed using optical microscopy (OM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), Micro-Raman spectroscopy (μ-RAMAN), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The investigation shows the mixture of minium, cinnabar and baryte in red preparation layer, quartz from the natural earth pigment in the underpaint layer and the pigments mixed with the additives in the paint layer. There are various pigments found in the paint layer ranging from emerald green, chalk, baryte, chrome yellow, ultramarine blue, carbon black and zinc white. Zinc white was widely utilized as the additive of green, yellow and blue paint layer. In addition, minium and carbon black were used to draw fine lines for image details. The degradation products of gypsum in the paint layer were evidenced by SEM-EDS and XRD. While the darkening of red lead in the red preparation layer was observed by OM. The trace of natural plant resin as a binding meium was found in S_Wood and S_Black samples evidencing by ATR-FTIR and Py-GC/MS. The 7 steps of painting technique were proposed by implementing all detailed scientific information.

Evaluation of mucilages efficacy in the removal of a natural adhesive (gacha) from a canvas by ATR – FTIR. First results

Nowadays the use of gelled systems to remove natural glues from cultural artefacts is very common, as they allow the application of controlled humidity to sensitive surfaces. These cleaning systems can be of natural or synthetic origin. The simplest gelled systems are made by adding a gelling agent (such us Laponite® RD, xanthan gum or agar-agar) to the cleaning agent.The aim of this research is to evaluate, using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR), the efficacy of hydrogels prepared from three commercial natural mucilages: guar, locust bean and konjac, in removing gacha from the reverse side of a canvas, and following the nowadays tendence that try to use eco-sustainable and bio-renewable cleaning materials. Gacha is an adhesive, made commonly with flour and animal glue as the main ingredients, used to line canvas paintings. The gels prepared were characterised by means of pH, electrical conductivity (EC), viscosity and aqueous phase release capacity. For this study, a mock-up of the canvas and the adhesive was prepared. Two application methods for the gels were tested: direct application and indirect using a physical barrier, with contact times of 15 and 30 min. The suitability of the mucilages in the elimination of the natural adhesive has been related to the decrease of the content of gacha on one side, and to the absence of gel residues after the cleaning process on the other, both parameters evaluated with ATR-FTIR analysis complemented with microscopic observations. The obtained results indicated that the removal of gacha was more effective with direct application, regardless of the mucilage used. On the other hand, mucilage residues are, in general, not significant, although in the case of direct application of guar and konjac for 15 min and locust bean and konjac for 30 min, the presence of mucilages traces were detected.

Development of Nisin-Loaded PEO Electrospun Nanofibers with Antibacterial Activity

The aim of this work was to develop and characterize nisin-loaded polyethylene oxide (PEO) nanofibers prepared by green electrospinning. The electrospinning operating parameters were optimized and nanofibers with 20,000 and 30,000 IU mL-1 of nisin were obtained. Scanning electron microscopy (SEM) imaging confirmed the formation of uniform, beadless nanofibers with diameters that ranged between 216 and 261 nm. Thermal stability studies showed that the electrospinning process led to the impairment of the crystalline structure of the polymer. Also, Raman spectroscopy tests revealed the interaction between nisin and PEO, while attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) showed that the addition of nisin did not alter the polymer backbone structure. In addition to this, the X-ray diffraction (XRD) analysis confirmed the semi-crystalline structure of nanofibers. Finally, the resulting nisin-loaded PEO nanofibers were tested against Staphylococcus aureus, confirming its antibacterial activity against this Gram-positive bacteria. Moreover, we also report, apparently for the first time, the antibacterial activity of nisin-loaded PEO nanofibers against Bacillus subtilis. These results expand their applications as green antibacterial biomaterials in areas such as food systems and biomedicine.

Emerging investigator series: open dumping and burning: an overlooked source of terrestrial microplastics in underserved communities.

Open dumping and burning of solid waste are widely practiced in underserved communities lacking access to solid waste management facilities; however, the generation of microplastics from these sites has been overlooked. We report elevated concentrations of microplastics (MPs) in soil of three solid waste open dump and burn sites: a single-family site in Tuttle, Oklahoma, USA, and two community-wide sites in Crow Agency and Lodge Grass, Montana, USA. We extracted, quantified, and characterized MPs from two soil depths (0-9 cm and 9-18 cm). The average of abundance of particles found at community-wide sites three sites (18, 460 particles kg-1 soil) equals or exceeds reported concentrations from currently understood sources of MPs including biosolids application and other agricultural practices. Attenuated total reflectance Fourier transformed infrared (ATR-FTIR) identified polyethylene as the dominant polymer across all sites (46.2-84.8%). We also detected rayon (≤11.5%), polystyrene (up to 11.5%), polyethylene terephthalate (≤5.1), polyvinyl chloride (≤4.4%), polyester (≤3.1), and acrylic (≤2.2%). Burned MPs accounted for 76.3 to 96.9% of the MPs found in both community wide dumping sites. These results indicate that solid waste dumping and burning activities are a major source of thermally oxidized MPs for the surrounding terrestrial environment with potential to negatively affect underserved communities.

Template assisted fabrication of nanoporous titanium dioxide coating on 316 L stainless steel for orthopaedic applications

BackgroundSurface modified metallic implants with nanoporous morphology finds extensive application as functional implant material as it mimics the biological conditions as well as matches the mechanical characteristics of the bone. The current study involves synthesis of nano-titania coating by the employment of PMMA as a templating agent and compared with widely used PEG 400. MethodThe titania coatings were synthesized by sol-gel methodology and deposited on 316 L SS by dip coating method. The coating morphology was characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), Scanning electron microscopy - energy dispersive X-ray analysis (SEM-EDX) and Atomic force microscopy (AFM). The bioactive nature of the coatings were evaluated by in vitro bioactivity study in simulated body fluid (SBF). The toxicity and cell adhesion of the coatings were analyzed by MTT assay. The ability of the coatings to resist corrosion was studied with potentiodynamic polarization and electrochemical impedance spectroscopy. Significant findingsThe changes in the cell adhesion behavior are observed for the different coatings. The TiO2 coatings exhibited excellent corrosion resistance. Besides, the nanoporous coating developed with PMMA as the templating agent revealed excellent bioactivity as well as higher corrosion resistance.

Classification of idiopathic recurrent spontaneous miscarriage using FTIR and Raman spectroscopic fusion technology

Recurrent spontaneous miscarriage refers to the repeated loss of two or more clinically detected pregnancies occurring within 24 weeks of gestation. No identifiable cause has been identified for nearly 50% of these cases. This group is referred to as idiopathic recurrent spontaneous miscarriage (IRSM) or miscarriage of unknown origin. Due to lack of robust scientific evidence, guidelines on the diagnosis and management of IRSM are not well defined and often contradictory. This motivates us to explore the vibrational fingerprints of endometrial tissue in these women. Endometrial tissues were collected from women undergoing IRSM (n = 20) and controls (n = 20) corresponding to the window of implantation. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra were obtained within the range of 400–4000 cm−1 using Agilent Cary 630 FTIR spectrometer. Raman spectra were also generated within the spectral window of 400–4000 cm−1 using Thermo Fisher Scientific, DXR Raman spectrophotometer. Based on the limited molecular information provided by a single spectroscopic tool, fusion strategy combining Raman and ATR-FTIR spectroscopic data of IRSM is proposed. The significant features were extracted applying principal component analysis (PCA) and wavelet threshold denoising (WTD) and fused spectral data used as input into support vector machine (SVM), adaptive boosting (AdaBoost) and decision tree (DT) models. Altered molecular vibrations associated with proteins, glutamate, and lipid metabolism were observed in IRSM using Raman spectroscopy. FTIR analysis indicated changes in the molecular vibrations of lipids and proteins, collagen dysregulation and impaired glucose metabolism. Combination of both spectroscopic data using mid-level fusion (MLF: 92% using AdaBoost and DT models) and high-level fusion (HLF: 92% using SVM models) methods showed improved IRSM classification accuracy as compared to individual spectral models. Our results indicate that spectral fusion technology hold promise in enhancing diagnostic accuracy of IRSM in clinical settings. Validation of these findings in a larger patient population is underway.

Molecular Insights into the Interfacial Phenomena at the Li Metal | Polymer Solid‐State Electrolyte in Anode‐Free Configuration During Li Plating‐Stripping via Advanced Operando ATR‐FTIR Spectroscopy

AbstractSolid‐state batteries are regarded as safe and high‐energy‐density candidates for next‐generation energy storage. However, gaining a mechanistic understanding of the interfacial phenomena under real electrochemically working conditions remains a major challenge for cells containing solid‐state electrolytes. This work presents an in‐house built attenuated total reflection fourier‐transform infrared (ATR‐FTIR) spectroscopy cell equipped with an internal temperature‐control unit. This cell is used for operando characterization of interfacial processes between plated Li and polymer during Li plating/stripping. As a proof of concept, a polymer electrolyte (cr‐PEO10LiTFSI) containing poly(ethylene oxide), Li bis‐(trifluoromethanesulfonyl)imide and crosslink‐initiator benzophenone (BP) is introduced on a copper mesh as current collector at 60 °C. The developed ATR‐FTIR spectroscopy setup provides detailed insights into the electrolyte degradation and reveals the crystallinity transformation of PEO at the interface during plating. Moreover, for the first time, the degradation of BP is observed. This compound, often overlooked in electrolyte systems due to its low concentration, is found to play a significant role in the interfacial electrochemistry process. Overall, this study provides a comprehensive overview of the characterization on the PEO electrolyte‐lithium metal interface and introduces a novel perspective on the reaction of BP as a crosslinking initiator in the solid‐state batteries.

Study of Interfacial Reaction Mechanism of Silicon Anodes with Different Surfaces by Using the In Situ Spectroscopy Technique.

The interfacial reaction of a silicon anode is very complex, which is closely related with the electrolyte components and surface elements' chemical status of the Si anode. It is crucial to elucidate the formation mechanism of the solid electrolyte interphase (SEI) on the silicon anode, which promotes the development of a stable SEI. However, the interface reaction mechanism on the silicon surface is closely related to the surface components. This work systematically investigates the interfacial reaction mechanism on silicon materials with three representative coatings of graphene, TiO2, and SiO2 by ex situ X-ray photoelectron spectroscopy (XPS) and dynamic analysis in operando attenuated total reflection-Fourier transform infrared (ATR-FTIR), in situ revealing the different ring-opening mechanisms of fluoro-ethylene carbonate (FEC) and ethylene carbonate (EC) on different silicon surfaces with varying electrical conductivities. Due to the different ring-opening mechanisms, the final decomposition product of FEC on the graphene/electrolyte interface is stable LiF, while on the oxide (native SiO2 or emerging TiO2) interface, it forms an unstable solid lithium compound •CH2CHFOCO2Li. This study demonstrates that the formation mechanism of the SEI on silicon-based electrodes is related to the electron conductivity of surface elements, providing a theoretical basis for further optimization of silicon-based composite materials.

Luliconazole-loaded nanostructured lipid carrier: formulation, characterization, and in vitro antifungal evaluation against a panel of resistant fungal strains

Luliconazole (LCZ) is a topical imidazole antifungal agent with broad-spectrum activity. However, LCZ encounters challenges such as low aqueous solubility, skin retention, and penetration, which reduce its dermal bioavailability and hinder its efficacy in drug delivery. The aim of the present study was to formulate, characterize, and evaluate the in vitro antifungal efficacy of luliconazole-loaded nanostructured lipid carriers (LCZ-NLCs) against a panel of resistant fungal strains. The LCZ-NLCs were synthesized using a modified emulsification-solvent evaporation technique. Characterization involved assessing parameters such as poly-dispersity index (PDI), zeta potential, encapsulation efficiency (EE %), Field Emission Scanning Electron Microscopy (FESEM), Differential Scanning Calorimetry (DSC) analysis, and Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR). Furthermore, in vitro drug release experiments, analysis of release kinetics, cytotoxicity assessments, and in vitro antifungal susceptibility tests were performed as part of the study. The findings indicated that LCZ-NLCs displayed nanoscale dimensions, uniform dispersion, and a favorable zeta potential. The encapsulation efficiency of LCZ in NLCs was approximately 90%. FESEM analysis revealed spherical nanoparticles with consistent shape. ATR-FTIR analysis indicated no chemical interaction between LCZ and excipients. In vitro drug release experiments demonstrated that LCZ-NLCs notably improved the drug’s dissolution rate. The stability testing confirmed consistent colloidal nanometer ranges in the LCZ-NLCs samples. Additionally, cytotoxicity tests revealed no toxicity within the tested concentration. Moreover, in vitro antifungal susceptibility tests demonstrated potent antifungal activity of LCZ-NLCs against the tested resistant fungal isolates. The study findings suggest that the LCZ-NLCs formulation developed in this research could be a promising topical treatment for superficial fungal infections, especially in cases of resistant infections. However, the study needs further ex vivo and in vivo tests to ensure safety and efficacy.

Evaluation of ATR-FTIR, HPLC-DAD, GC-MS, and GC-IR for the Analysis of 145 Street Drug Samples From Drug Checking Services.

Drug checking services (DCS) are entities that allow recreational drug users to have street drug samples analyzed. Diverse analytical methods are applied for DCS, ranging from test strips to mass spectrometry (MS). This work evaluates the performance and utility of common methodologies used for DCS operating with off-site drug testing, while additionally assessing the potential of gas chromatography coupled to vapor phase infrared spectroscopy (GC-IR). Gas chromatography MS (GC-MS), GC-IR, and high-performance liquid chromatography with diode array detector (HPLC-DAD) were evaluated based on the analysis of 145 street drug samples obtained from two Swiss DCS. Additionally, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) was applied and is briefly discussed. A combined total of 245 analytes (including adulterants and cutting agents) were detected. GC-MS presented the greatest number of detected compounds, with a sensitivity of 96% compared with the sum of all analytes, followed by HPLC-DAD with 82%, while GC-IR showed limited sensitivity with 70%. GC-IR underperformed regarding the detection of low-abundant adulterants and of the main active ingredients in strongly adulterated samples. This study discusses the limitations and strengths of the evaluated methods in the specific context of DCS, while providing insights into the occurrence of false declarations (differing analytical results compared with alleged drug identity) and the distributions of adulterants and cutting agents in street drug samples. Based on our results, complementary approaches are considered the most valuable. Finally, the promotion of comprehensive guidelines regarding the quality and suitability of analytical methods for DCS would be highly desired.

Combination ATR-FTIR with Multiple Classification Algorithms for Authentication of the Four Medicinal Plants from Curcuma L. in Rhizomes and Tuberous Roots

Curcumae Longae Rhizoma (CLRh), Curcumae Radix (CRa), and Curcumae Rhizoma (CRh), derived from the different medicinal parts of the Curcuma species, are blood-activating analgesics commonly used for promoting blood circulation and relieving pain. Due to their certain similarities in chemical composition and pharmacological effects, these three herbs exhibit a high risk associated with mixing and indiscriminate use. The diverse methods used for distinguishing the medicinal origins are complex, time-consuming, and limited to intraspecific differentiation, which are not suitable for rapid and systematic identification. We developed a rapid analysis method for identification of affinis and different medicinal materials using attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR) combined with machine learning algorithms. The original spectroscopic data were pretreated using derivatives, standard normal variate (SNV), multiplicative scatter correction (MSC), and smoothing (S) methods. Among them, 1D + MSC + 13S emerged as the best pretreatment method. Then, t-distributed stochastic neighbor embedding (t-SNE) was applied to visualize the results, and seven kinds of classification models were constructed. The results showed that support vector machine (SVM) modeling was superior to other models and the accuracy of validation and prediction was preferable, with a modeling time of 127.76 s. The established method could be employed to rapidly and effectively distinguish the different origins and parts of Curcuma species and thus provides a technique for rapid quality evaluation of affinis species.

Impact of Surface Adsorption on DNA Structure and Stability: Implications for Environmental DNA Interactions with Iron Oxide Surfaces.

Environmental DNA (eDNA), i.e., DNA found in the environment, can interact with various geochemical surfaces, yet little is known about these interactions. Mineral surfaces may alter the structure, stability, and reactivity of eDNA, impacting the cycling of genetic information and the reliability of eDNA-based detection tools. Understanding how eDNA interacts with surfaces is crucial for predicting its fate in the environment. In this study, we examined the surface interaction and stability of herring testes DNA, a model system for eDNA, on two common iron oxide phases present in the environment: α-FeOOH (goethite) and α-Fe2O3 (hematite). Utilizing spectroscopic probes, including attenuated total reflection Fourier-transform infrared (ATR-FTIR) and UV-vis spectroscopy, we quantified the DNA adsorption capacity at pH 5 and determined its secondary structure. DNA adsorbed irreversibly at pH 5 and 25 °C, primarily through its phosphate groups, and retained the solution-phase B-form structure. However, the infrared data also indicated some distortion of the B-form likely due to additional interactions between nitrogenous bases when adsorbed on the α-Fe2O3 particle surfaces. The distortion in the double helical structure of adsorbed DNA on α-Fe2O3 led to a lower melting temperature (Tm) of 60 °C compared to 70 °C for DNA in solution. In contrast, DNA adsorbed on α-FeOOH melted at higher temperatures relative to solution-phase DNA and in two distinct phases. Upon testing adsorbed DNA stability at higher pH values, there were distinct differences between the two iron oxide phases. For α-FeOOH, nearly 50% of the DNA desorbed from the surface when the solution pH changed from 5 to 8, while less than 5% desorbed from α-Fe2O3 under the same conditions. Overall, these findings underscore the importance of mineral-specific eDNA-surface interactions and their role in adsorbed eDNA stability, in terms of DNA melting and the impact of solution-phase pH changes.

Study of Water Resistance of Polyurethane Coatings Based on Microanalytical Methods.

This study investigates the effect of microstructural changes in polyurethane coatings on their water resistance properties. Polyurethane coatings with varying diluent contents were prepared and tested for water penetration resistance and mechanical property retention. The time-dependent behavior of water within the coatings at different immersion durations was analyzed using low-field nuclear magnetic resonance (NMR). Furthermore, the free volume and characteristic molecular groups of each coating were analyzed using microscopic techniques, including positron annihilation lifetime spectroscopy (PALS) and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Results indicate that diluent content significantly alters the microstructure of the coatings. With increasing diluent content, both the average pore volume and free volume fraction initially decrease and then increase, while characteristic molecular groups, including hydrophilic groups, gradually decline. The water resistance performance of the coatings was significantly influenced by the combined effects of free volume and characteristic molecular groups. Among the five tested coating formulations, coatings with diluent contents of 20% and 25% showed a superior water penetration resistance, higher retention of mechanical properties after immersion, and relatively low total content of bound and free water at all immersion ages. The entropy weight method and the equal weight method were used to assess the overall water resistance, with the following ranking of scores: f20 > f25 > f30 > f15 > f10. This study offers theoretical support to guide the design and practical application of polyurethane coatings in real-world engineering projects.

Porphyrin-Based Aluminum Metal-Organic Framework with Copper: Pre-Adsorption of Water Vapor, Dynamic and Static Sorption of Diethyl Sulfide Vapor, and Sorbent Regeneration.

Metal-organic frameworks (MOFs) are hybrid inorganic-organic 3D coordination polymers with metal sites and organic linkers, which are a "hot" topic in the research of sorption, separations, catalysis, sensing, and environmental remediation. In this study, we explore the molecular mechanism and kinetics of interaction of the new copper porphyrin aluminum metal-organic framework (actAl-MOF-TCPPCu) compound 4 with a vapor of the volatile organic sulfur compound (VOSC) diethyl sulfide (DES). First, compound 4 was synthesized by post-synthetic modification (PSM) of Al-MOF-TCPPH2 compound 2 by inserting Cu2+ ions into the porphyrin ring and characterized by complementary qualitative and quantitative chemical, structural, and spectroscopic analysis. Second, the interaction of compound 4 with DES vapor was analyzed dynamically by the novel method of in situ time-dependent attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy at controlled humidity levels. The sorbent-adsorbate interactions, as analyzed by the shifts in IR peaks, indicate that the bonding includes the hydroxy O-H, carboxylate COO-, and phenyl groups. The kinetics of sorption obeys the Langmuir pseudo-first-order rate law. The pre-adsorption of water vapor by compound 4 at the controlled relative humidity under static (equilibrium) conditions yields the binary stoichiometric adsorption complex (Al-MOF-TCPPCu)1.0(H2O)8.0. The pre-adsorption of water vapor makes the subsequent sorption of DES slower, while the kinetics obey the same rate law. Then, static pre-adsorption of water vapor was followed by static sorption of DES vapor, and the ternary adsorption complex (Al-MOF-TCPPCu)1.0(H2O)8.0(DES)3.8 was obtained. Despite the pre-adsorption of significant amounts of water, the binary complex adsorbs a large amount of DES: ca. 36.6 wt. % (per compound 4). Finally, the ternary complex is facilely regenerated by gentle heating under vacuum. Compound 4 and related MOFs are promising for adsorptive removal of vapor of DES and related VOSCs from dry and humid air.

Thermal, Molecular Dynamics, and Mechanical Properties of Poly(Ethylene Furanoate)/Poly(ε-Caprolactone) Block Copolymers.

This study presents the synthesis and characterization of a series of multiblock copolymers, poly(ethylene 2,5-furandicarboxylate)-poly(ε-caprolactone) (PEF-PCL), created through a combination of the two-step melt polycondensation method and ring opening polymerization, as sustainable alternatives to fossil-based plastics. The structural confirmation of these block copolymers was achieved through Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), ensuring the successful integration of PEF and PCL segments. X-ray Photoelectron Spectroscopy (XPS) was employed for chemical bonding and quantitative analysis, providing insights into the distribution and compatibility of the copolymer components. Differential Scanning Calorimetry (DSC) analysis revealed a single glass transition temperature (Tg), indicating the effective plasticizing effect of PCL on PEF, which enhances the flexibility of the copolymers. X-ray Diffraction (XRD) studies highlight the complex relationship between PCL content and crystallization in PEF-PCL block copolymers, emphasizing the need to balance crystallinity and mechanical properties for optimal material performance. Broadband Dielectric Spectroscopy (BDS) confirmed excellent distribution of PEF-PCL without phase separation, which is vital for maintaining consistent material properties. Mechanical properties were evaluated using Nanoindentation testing, demonstrating the potential of these copolymers as flexible packaging materials due to their enhanced mechanical strength and flexibility. The study concludes that PEF-PCL block copolymers are promising candidates for sustainable packaging solutions, combining environmental benefits with desirable material properties.

Recent advances in research from plastic materials to microplastics

Plastics have become ubiquitous in our lives. Due to the ever-increasing population, rapid urbanization, and industrial advancement, the use of plastics has increased manifold. These plastic materials often disintegrate into microplastics (MPs) which are less than 5mm in size. MPs mostly enter aquatic habitats through improper waste management, illegal dumping, and unavoidable and unintentional discharges that take place during construction, manufacturing, farming, domestic consumption, and recreational activities. This review centers on exploring the origin, occurrence, and possible adverse effects of MPs on human well-being. Of the 485 literature reviewed for the study between 2014- 2023, 105 were found to be related to the MPs which were spread over 10 themes. The maximum number of papers were on sources of MPs, followed by MPs in freshwater ecosystems and waste management. The least number of literature was from the themes, transport of MPs and MPs in the soil environment. The literature was published mostly in China, India, Europe, and the Americas. Other countries like Australia, Latin America, Africa, and the Middle East contribute very little. The literature scan reveals that only 9% of all the generated plastic waste material is recycled, 12% is burned, and 79% of plastic litter is dumped in landfills and oceans. The dumped plastic settles and pollutes a variety of environmental matrices. MPs are intentionally manufactured to be added to personal care products that are washed down the drains through sewage or industrial wastewater. These MPs vary in density and colour, subject to the polymer type, and are present in varying sizes and concentrations in aquatic environments. The characterization of MPs originating from different types of polymer materials, in the reviewed literature, was performed based on the data obtained from Scanning Electron Microscopy Energy Dispersive Spectroscopy (SEM-EDS), Attenuated Total Reflection Fourier Transform Infra-Red spectroscopy (ATR-FTIR), Raman spectroscopy, and Atomic Force Microscopy (AFM). MPs have the potential to absorb harmful hydrophobic pollutants from the surroundings resulting in an indirect transfer of contaminants into the food web. Such MPs enter and affect humans, causing problems with the reproductive system, body weight, sex ratio, and live births. MPs pose a serious threat to organisms when ingested since they can obstruct the digestive tract, leading to oxidative and pathological stress, slowing down growth, and interfering with reproduction. Apart from the above, a comprehensive analysis of MP pollution, as well as its effect on human beings and the environment, has been discussed in terms of source identification and abundance. Also, has been discussed is a detailed review of the existing waste material recycled into new materials or reused without alteration or degradation to produce new energy sources. In the end, integrated strategies have been proposed to prevent the input of plastic waste material into the environment, by source control, improved plastic waste management, and techniques for degradation and conversion of MPs.

Exploring Spent Coffee Grounds: Comprehensive Morphological Analysis and Chemical Characterization for Potential Uses.

The agroindustry generates substantial quantities of byproducts, particularly in coffee production, which yields significant waste, most notably spent coffee grounds (SCGs). This study explores the potential of SCGs as a versatile resource for applications in both food and nonfood sectors. A comprehensive chemical analysis revealed that SCGs consist of 30.2 wt.% cellulose, 25 wt.% hemicellulose, and 12 wt.% lignin. Morphological characterization was performed using field emission scanning electron microscopy (FESEM). Additional analyses included attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA). ATR-FTIR identified key polysaccharides and oils, whereas TGA offered insights into the thermal degradation behavior of SCGs, confirming the presence of typical plant cell wall components. X-ray diffraction (XRD) patterns revealed low crystallinity, consistent with SCGs' amorphous structure. Mineral content was assessed using inductively coupled plasma atomic emission spectrometry (ICP-AES) and atomic absorption spectrophotometry (AAS). The results showed that mineral concentrations in SCGs (per 0.01 kg) were within recommended daily intake limits, confirming their safety for potential human consumption. These findings establish SCGs as a valuable lignocellulosic biomass with applications in composite materials. Additionally, it can serve as an organic soil amendment after fermentation to prevent stress on plants. This approach supports effective waste management and advances resource sustainability practices in the agro-industrial sector.