Spectroscopy Analysis Research Articles

Phytochemical, spectroscopic analysis and antifungal activity on bell peppers of hydrothermal bioactive metabolites of Humulus lupulus L. extracts.

This study aimed to evaluate the impact of temperature on the potential extraction of bioactive compounds from aqueous hop extract samples. The main bioactive components were characterised and analysed by LC-MS/MS, FT-IR, phenolic compounds and total flavonoids. Antifungal activity was evaluated in vitro and in vivo in bell peppers. LC-MS/MS analysis demonstrated increases and decreases of bioactive compounds in both extracts depending on the extraction temperature of 25 or 65 °C. The bioactive compounds showed significant changes in the bands between 2786 to 3600 cm-1 and 1022 to 1729 cm-1 in the FT-IR spectrum. The highest antifungal activity against the microorganisms was observed in the EkuanotMT extract at an extraction temperature of 65 °C. The in vivo test with bell peppers presented antifungal activity during five days of evaluation under normal environmental conditions without refrigeration, presenting ≤ 52% of the disease due to F. oxysporum and A. solani.

Anion Storing Boron Nitride Hybrid Nanosheets for High-Performance Dual Ion and Zinc Alkaline Full Cells.

Hexagonal boron nitride (BN), a well-known member of 2D materials, has a structure similar to graphene and is often referred to as white graphene. Despite its unique physical and chemical properties for energy storage applications, there have been very few studies on how BN stores anion carriers. Herein, the hybrid architecture and anion storage mechanism of BN nanosheets for high-performance hybrid energy storage full cells based on dual-ion and Zinc (Zn) alkaline systems is demonstrated. The chemical bonding between BN and reduced graphene oxide (rGO) is attributed to the formation of the heterointerface, which facilitates the charge transfer kinetics during an OH storing process. Based on the reversible surface redox reaction of BN and rGO hybrid (BN@rGO) confirmed by computational and spectroscopic analyses, the BN@rGO electrode is applied to both Na and OH dual-ion and Zn alkaline full cells. In the dual-ion system, Ti3C2‖BN@rGO full cells extended the operating voltage range up to 1.7V, delivering a cell capacity of 49.4mAhg-1 at 1000mAg-1 and retaining 80% of its initial capacity after 40000 cycles. In the Zn alkaline system, Zn‖BN@rGO full cells achieved a cell capacity of 58.1mAhg-1 at 1000mAg-1 and retained 80% capacity over 90000 cycles.

Enhancing high‐temperature stability of limonene‐loaded nanostructured lipid carriers with various solid lipids

AbstractIn this research, nanostructured lipid carriers (NLCs) loaded with limonene were developed using various solid lipids. The impact of high temperatures on the characteristics of NLCs was investigated. NLCs exhibited zeta potential values exceeding |30| mV, indicating excellent homogeneity and stability. Increasing the carbon chain length of monoglycerides from C15 to C21 resulted in a corresponding increase in particle size of NLCs from 219.1 ± 1.1 to 243.3 ± 0.9 nm. However, the particle size remained relatively constant with an increase in the number of solid lipid carbon chains. Encapsulation efficiency of limonene increased from 66.0 ± 0.7% to 86.2 ± 0.8% with an increase in the number of solid lipid carbon chains. The result showed that more ester bonds facilitated the dissolution of the target and enhanced the interaction forces between solid lipids and the target. X‐ray diffraction, Fourier transform‐infra‐red spectroscopy and differential scanning calorimetry analyses confirmed effective encapsulation of limonene in NLCs, resulting in good stability. NLCs prepared from various solid lipids exhibited varying properties. Glycerol triglyceride demonstrated superior stability and homogeneity of nanoparticles under high‐temperature conditions compared to other solid lipids. This study provides enhancing the thermal stability of limonene‐loaded NLCs and proposes a novel approach for their practical application.

Clay Minerals and Long-Term Fertilization Effects on Soil Organic Carbon Stocks, Soil Carbon Pools, and Soil Enzymes in an Inceptisol of Coimbatore, Tamil Nadu

ABSTRACT Soil Organic Carbon (SOC) is an important indicator for soil health and quality. The present study was conducted in five-decade-old Long-Term Fertilizer Experiment involving the finger millet−maize cropping sequence in an Inceptisol to examine the effects of inorganic fertilizers and manures on soil organic carbon stock in relation to C sequestration. This study was based on 10 treatments: 50%NPK, 100%NPK, 150%NPK, 100%NPK + HW, 100%NPK + ZnSO4, 100%NP, 100%N, 100%NPK + FYM, 100%NPK (− S), and control. We assess the clay mineral interaction with soil organic carbon stock and soil enzyme activity. The semi-quantification and characterization of clay minerals were sourced from X-ray diffraction (XRD) analysis, and the SOC stock was calculated based on SOC concentration, Bulk density, and Depth. From the study, results revealed that clay minerals were studied by XRD and FTIR spectroscopy analysis. The results revealed that dominant clay minerals in the experimental soil were in the order of Montmorillonite, 2:1 interstratified minerals, Vermiculite, and Illite, and the buildup of SOC stock raised from 6.3 Mg C ha−1 to 12.9 Mg C ha−1 over five decades. The maximum SOC stock of 12.9 Mg ha−1 was recorded in 100% NPK + FYM while the control registered 7.5 Mg C ha−1. The study conclude that balanced fertilization of 100% NPK with FYM contributed toward the increase in SOC, SOC stock, and carbon sequestration for improving soil fertility status.

Optimization of Brilliant Blue R photocatalytic degradation by silver nanoparticles synthesized using Chlorella vulgaris.

Synthesis of silver nanoparticles (Ag NPs) using microalgae is gaining recognition for its environmentally friendly and cost-effective nature while maintaining high activity of NPs. In the present study, Ag NPs were synthesized using a methanolic extract of Chlorella vulgaris and subjected to calcination. The X-ray diffraction (XRD) analysis showed a crystalline nature of the products with Ag2O and Ag phases with an average crystalline size of 16.07nm before calcination and an Ag phase with 24.61nm crystalline size after calcination. Fourier transform infrared spectroscopy (FTIR) revealed the capping functional groups on Ag NPs, while scanning electron microscopy (SEM) displayed their irregular morphology and agglomeration after calcination. The organic coating was examined by energy-dispersive X-ray spectroscopy (EDX) and thermogravimetric (TGA) analyses, confirming the involvement of the metabolites. The UV-Vis analysis showed a difference in optical properties due to calcination. Synthesized Ag NPs were applied for the photodegradation of hazardous dye Brilliant Blue R in visible light. Different values of light intensity, catalyst dose, initial dye concentration, and pH were tested to identify the optimal set of operating conditions. The highest degradation efficiency of 90.6% with an apparent rate constant of 0.04402min-1 was achieved after 90min of irradiation in the highest tested catalyst dosage.

Synergy Effect of High K-Low Ca-High Si Biomass Ash Model System on Syngas Production and Reactivity Characteristics during Petroleum Coke Steam Gasification

The synergy effect of high K-low Ca-high Si biomass ash-based model system (BAMS) on the synthesis gas output and reaction characteristics of petroleum coke (PC) steam gasification process was studied using three biomass ash (BA) components, KCl, SiO2, and CaCO3, which were used as the model compounds. In the ternary model system, the steam gasification experiment of PC was conducted using a fixed bed reactor and gas phase chromatography. The synergistic effects of binary and ternary components in the ternary model system on the gasification of PC were obtained. These investigations were based on the data from the gas analysis and examined the gasification reaction process, syngas release behavior, and reaction characteristics. This study examined the effects of binary and ternary components in the ternary model system on the evolution of semi-char structure during PC gasification. This correlation revealed the synergistic effect of the model system on PC gasification. Scanning electron microscope (SEM) and Raman spectroscopy were used to characterize the structure and surface microstructure of the gasification semi-char. The results showed that the yields of different gases in the ternary model system were in H2 > CO > CO2. Compared with single PC gasification, the yields of H2, CO, syngas, and carbon conversion were increased by 29.42 mmol/g, 20.40 mmol/g, 56.68 mmol/g, and 0.35, respectively. All other components in the ternary model system with high K-low Ca-high Si demonstrated catalytic effect, except for SiO2 and the Ca-Si system, which showed inhibitory effects on syngas release and reaction features. Integrating SEM and Raman spectroscopic analyses, it was elucidated that CaCO3 and KCl diminished the degree of graphitization in semi-char through interactions with the carbonaceous matrix. This phenomenon facilitated the gasification process and exhibited a synergistic effect. Secondly, SiO2 will react with CaCO3 and KCl, producing inert silicates and inactivating these compounds, leading to the decline of catalysis.

Medullins A-H, Sesquiterpenes from Perenniporia medulla-panis, and Their Cellular Signaling Mechanism in HDF Cells.

A chemical investigation of an ethyl acetate-soluble layer in the culture broth of Perenniporia medulla-panis resulted in the isolation of eight novel sesquiterpenes conjugated Gly (1), l-Val (2), l-Ala (3), l-Tyr (4), l-Thr (5), l-Ile (6), l-Leu (7), and l-Phe (8). Elucidation of their structures was performed through comprehensive spectroscopic analysis. The absolute configuration of the sesquiterpene skeleton was ascertained using modified Mosher's methods. The configurations of the amino acid units in compounds 2-8 were identified through acid hydrolysis followed by LC-MS analysis employing Marfey's method. Compounds 1-3 and 5-8 showed significant regulating effect on MAP kinase activity (p-ERK and p-JNK) in human diploid fibroblast (HDF) cells.

An innovative biphasic reaction system for highly selective benzene hydroxylation based on photocatalytic polymer composites

The hydroxylation of benzene to phenol in presence of hydrogen peroxide was performed using a new biphasic system consisting of a solid phase, a photocatalytically active monolithic polymer composite, immersed in an aqueous phase in which H2O2 is dissolved. In detail, ZnO photocatalytic particles were embedded into the hydrophobic syndiotactic polystyrene (sPS) polymer. Zinc oxide nanostructures (ZnO NSs) were synthesized by an electrochemical procedure. The surface morphology and structure of ZnO nanoparticles and ZnO‐sPS monolithic aerogel composite (ZnO/sPS) were investigated by scanning electron microscopy, X‐ray diffraction and X‐ray photoelectron spectroscopy analysis. Photocatalytic results evidenced that, under UV irradiation, both ZnO NSs and biphasic system water‐photocatalytic composites had a high benzene oxidative property but with very low phenol yield (<2%) at pH=7. To enhance the phenol selective formation, the pH of aqueous solution surrounding the photocatalytic polymer composite was modified. A phenol yield of about 94% and benzene conversion higher than 99% was obtained in alkaline conditions (pH=11).

One New Quinazoline-Containing Diketopiperazine Isolated from the Marine-Sponge-Derived Fungus Penicillium sp. SCSIO41043.

One new quinazoline-containing diketopiperazine (1), along with 24 known compounds including nine alkaloids (2-9, and 25), thirteen lactones (10-22), aspterric acid (23), and catechol (24), were isolated from the marine sponge-derived Penicillium sp. SCSIO41043. Their planar structures were unequivocally elucidated by spectroscopic analysis. The absolute configuration of 1 was determined by a comparison of reported and experimental electronic circular dichroism (ECD) spectra. Compound 16 was found to notably inhibit the growth of five pathogenic bacteria and fungi with MIC values ranging from 0.5-16.0 μg/mL. Compounds 7, 17, 20, and 22 demonstrated moderate activity against Micrococcus luteus with MIC values ranging from 35.6 to 71.1 μg/mL. Moreover, 1-3 displayed different degrees of antioxidant activity with EC50 values of 0.98, 0.60, 0.46 mg/mL, respectively.

Preparation, Characterization, In Vitro Biological Evaluation, DFT Calculations, and Molecular Docking Investigations of 1H-Imidazole-2-Carboxylic acid and Histidine-Based Mixed-Ligand Complexes.

Mixed-ligand complexes incorporating 1H-Imidazole-2-Carboxylic acid (IMCA) and Histidine (LHIS) show promise for biomedical and biotechnological applications. This study synthesizes and characterizes FeIMCALHIS, CoIMCALHIS, and NiIMCALHIS coordination compounds using metal chloride salts (FeCl3.6H2O, CoCl2.6H2O, NiCl2.6H2O) in ethanolic solutions. The complexes are characterized by spectroscopic methods (IR, UV-vis, and mass spectra), elemental analysis, conductivity, magnetic, and thermal analysis. Molar conductivity indicates their non-electrolytic nature. UV-vis spectra reveal absorption bands with pathochromic shifts, and electronic spectra show characteristic metal-ligand transitions, indicating their structural configuration and coordination geometry. 3D geometry optimization shows six-coordination around Fe(III) and Co(II) in FeIMCALHIS and CoIMCALHIS, and four-coordination around Ni(II) in NiIMCALHIS. Analysis of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) suggests decreased electron donation ability upon coordination. Electronic structure parameters (HOMO, LUMO, ionization potential, energy gap, electron affinity, chemical potentials, and electronegativity) provide further insights into stability and reactivity. The metal complexes exhibit enhanced antimicrobial, antioxidant, and anti-inflammatory activity compared to individual ligands, with FeIMCALHIS showing notable antimicrobial activity. Molecular docking analysis reveals strong binding interactions with target proteins, highlighting their potential therapeutic applications.

Charge Carrier Dynamics in Bandgap Modulated Covellite-CuS Nanostructures.

Copper Sulfide (CuS) semiconductors have garnered interest, but the effect of transition metal doping on charge carrier kinetics and bandgap remains unclear. In this study, the interactions between dopant atoms (Nickel, Cobalt, and Manganese) and the CuS lattice using spectroscopy and electrochemical analysis are explored. The findings show that sp-d exchange interactions between band electrons and the dopant ions, which replace Cu2+, are key to altering the material's properties. Specifically, these interactions result in a reduced bandgap by shifting the conduction and valence band edges and increasing carrier concentration. It is observed that undoped CuS nanoflowers exhibit a carrier lifetime of 2.16 ns, whereas Mn-doped CuS shows an extended lifetime of 2.62 ns. This increase is attributed to longer carrier scattering times (84 ± 5 fs for Mn-CuS compared to 53 ± 14 fs for CuS) and slower trapping (∼1.5 ps) with prolonged de-trapping (∼100 ps) rates. These dopant-induced energy levels enhance mobility and carrier lifetime by reducing recombination rates. This study highlights the potential of doped CuS as cathode materials for sodium-ion batteries and emphasizes the applicability of metal sulfides in energy solutions.

Enhancing the Performance of Nanocrystalline SnO2 for Solar Cells through Photonic Curing Using Impedance Spectroscopy Analysis

Wide-bandgap tin oxide (SnO2) thin-films are frequently used as an electron-transporting layers in perovskite solar cells due to their superior thermal and environmental stabilities. However, its crystallization by conventional thermal methods typically requires high temperatures and long periods of time. These post-processing conditions severely limit the choice of substrates and reduce the large-scale manufacturing capabilities. This work describes the intense-pulsed-light-induced crystallization of SnO2 thin-films using only 500 μs of exposure time. The thin-films’ properties are investigated using both impedance spectroscopy and photoconductivity characteristic measurements. A Nyquist plot analysis establishes that the process parameters have a significant impact on the electronic and ionic behaviors of the SnO2 films. Most importantly, we demonstrate that light-induced crystallization yields improved topography and excellent electrical properties through enhanced charge transfer, improved interfacial morphology, and better ohmic contact compared to thermally annealed (TA) SnO2 films.

Trifunctional Graphene-Sandwiched Heterojunction-Embedded Layered Lattice Electrocatalyst for High Performance in Zn-Air Battery-Driven Water Splitting.

Zn-air battery (ZAB)-driven water splitting holds great promise as a next-generation energy conversion technology, but its large overpotential, low activity, and poor stability for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) remain obstacles. Here, a trifunctional graphene-sandwiched, heterojunction-embedded layered lattice (G-SHELL) electrocatalyst offering a solution to these challenges are reported. Its hollow core-layered shell morphology promotes ion transport to Co3S4 for OER and graphene-sandwiched MoS2 for ORR/HER, while its heterojunction-induced internal electric fields facilitate electron migration. The structural characteristics of G-SHELL are thoroughly investigated using X-ray absorption spectroscopy. Additionally, atomic-resolution transmission electron microscopy (TEM) images align well with the DFT-relaxed structures and simulated TEM images, further confirming its structure. It exhibits an approximately threefold smaller ORR charge transfer resistance than Pt/C, a lower OER overpotential and Tafel slope than RuO₂, and excellent HER overpotential and Tafel slope, while outlasting noble metals in terms of durability. Ex situ X-ray photoelectron spectroscopy analysis under varying potentials by examining the peak shifts and ratios (Co2+/Co3+ and Mo4+/Mo6+) elucidates electrocatalytic reaction mechanisms. Furthermore, the ZAB with G-SHELL outperforms Pt/C+RuO2 in terms of energy density (797Wh kg-1) and peak power density (275.8mW cm-2), realizing the ZAB-driven water splitting.

Influence of annealing on the physicochemical properties of 2L ferrihydrite synthesized by radiation-chemical method from iron (III) nitrate

In this study, ferrihydrite (Fhy) nanoparticles (NPles) synthesized by the radiation chemical method (RCM) from an iron nitrate alcohol solution were annealed in air at temperatures ranging from 100 to 1200 ºC. The effects of annealing temperature on the phase transformation and basic physicochemical properties of the annealed Fhy nanopowders (NPs) were investigated. Fhy NPles annealed at 400 ºC and above can be converted to hematite NPles. The X-ray diffraction (XRD) pattern of the RCM-synthesized product corresponded to two-line (2 L) Fhy NPles, with no additional peaks, confirming their chemical purity. Up to 200 ºC, no significant phase transformation of Fhy NPles was observed; at 300 ºC, Fhy transformed into maghemite, which further transformed into hematite at 400 ºC. TEM/HRTEM analysis showed the formation of mesoporous agglomerates consisting of amorphous-crystalline NPles approximately 2 nm in size in the Fhy S95 sample annealed at 95 ºC. Selected area electron diffraction (SAED) images indicated the presence of two crystalline phases in sample S95: FeO and zero-valence Fe. The specific surface area (SSA) of mesoporous Fhy NPles varied non-monotonically between 100 and 500 ºC, peaking at 53.2 m2/g at 300 ºC. X-ray photoelectron spectroscopy (XPS) analysis revealed a minor nitrogen impurity, likely from the initial iron nitrate precursor, and a significant amount of adsorbed carbon on the developed porous surface of Fhy NPles. The phase composition of annealed Fhy samples correlated with their photoluminescent (PL) spectra. In samples S400 and S500 containing hematite, a small ferromagnetic contribution emerged, disrupting the linear magnetization-field dependence observed in samples S0-S200. Thus, the properties of 2 L Fhy nanoparticles produced by the radiation chemical method can be modified through thermal annealing while maintaining their potential biomedical applications as nanocontainers for drug delivery and contrast agents.

Rapid UV-Vis spectrophotometric method aided by firefly-PLS models for the simultaneous quantification of ciprofloxacin, lomefloxacin, and enrofloxacin in their laboratory mixture, dosage forms and water samples: greenness and blueness assessment

Herein, a novel UV spectrophotometric method coupled with chemometric tools was developed for the simultaneous determination of three fluoroquinolone antibiotics: ciprofloxacin, lomefloxacin, and enrofloxacin. Such integration of UV spectroscopy and chemometric analysis proved to be a simple, rapid, and cost-effective approach for the quantification of these clinically important pharmaceutical compounds and aid in their quality control analysis. The method employed firefly algorithm for variable selection and partial least squares (PLS) regression for model calibration. The developed method was validated by independent test set in addition the accuracy, intra and inter-day precision as per ICH guidelines which showed a satisfactory performance with mean recovery ranged between 98.18 and 101.83 with %RSD < 2. Besides, the developed method displayed ultrasensitive levels with LODs (0.0803, 0.1125, 0.1309 µg/mL) and LOQs (0.2434, 0.3409, 0.3968 µg/mL) for ciprofloxacin, lomefloxacin, and enrofloxacin, respectively. The greenness and blueness of the developed method were also evaluated using the recently proposed Analytical GREEnness metric approach (AGREE) and Blue applicability grade index (BAGI) tools, which showed a high AGREE score of 0.79 and a BAGI score of 77.5. These results indicate that the developed method provides an environmentally friendly alternative to the traditionally used chromatographic techniques, while maintaining high analytical practicability. Finally, the application of the developed methodology was demonstrated on real pharmaceutical and tap water samples, and the results were in good agreement with those obtained by the reference HPLC method indicating the reliability and suitability of the proposed spectrophotometric method for routine analysis of fluoroquinolone antibiotics.

Enhanced degradation performance toward para-nitrophenol of adapted immobilized microbial community on coconut coir

Nitrophenol pollutants, including para-nitrophenol (p-NP), are known for their harmful environmental impact due to their persistence, toxicity, and widespread distribution in water sources. While biodegradation generally offers a more effective removal of organic pollutants compared to chemical or physical methods, degrading persistent and toxic compounds like p-NP remains challenging. In this study, a microbial community derived from food processing wastewater was immobilized on coconut coir and adapted to p-NP before being employed for p-NP biodegradation. The spectroscopic analysis demonstrates the effective biodegradation performance of the adapted microbial community, achieving 99% degradation of 50 mg L⁻1 p-NP in 38 min and 250 mg L⁻1 p-NP in 4.65 h. The degradation ability of immobilized cells was determined across a broad range of stirring speeds, temperatures, pH levels, and p-NP solution volumes. Complete mineralization of p-NP was confirmed by chemical oxygen demand (COD) measurements of the treated solution and in-situ CO2 generation. Notably, the p-NP degradation performance of the adapted immobilized microbial community remained stable for the first 40 days, with only a slight decrease observed after 47 days of cold preservation at 4 °C. An average p-NP degradation rate of 0.75 mg L⁻1 min⁻1 was maintained over 54 consecutive runs. Significant alterations in microbial diversity were identified through 16S metabarcoding analysis. The unadapted microbial community comprised a diverse range of genera, while the adapted community showed reduced diversity with an enrichment of specific genera known for p-NP degradation, such as unidentified members of the Micrococcaceae family, Paenarthrobacter spp., and Zoogloea spp.

High-temperature tribological behavior of plasma sprayed GNPs-reinforced YSZ coating over 316L stainless steel

Despite numerous studies focusing on the use of stainless steel (SS316L) in high-temperature tribological applications, there remains a significant research gap regarding the improvement of its sustainability and lifetime in these harsh conditions. Herein, the plasma-sprayed graphene nanoplatelets (GNPs) reinforced yttria stabilized zirconia (YSZ) coating was deposited over SS316L to enhance its viability for high-temperature tribological applications. The coatings have been deposited using fused and crushed powder to improve the sintering resistance of the coatings. The structural and mechanical properties of coatings were observed using XRD, Raman, FE-SEM, and Vickers microhardness, respectively. The composite coating offered a significant improvement in the reduction of wear rate (∼45 % compared to YSZ coating) at 873 K and coefficient of friction by ∼51 % from 300 K to 873 K. Further, the findings were investigated by Raman spectroscopy, High-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy analysis to understand the effect of GNPs reinforcement. This study provides a pathway to improve the applicability of SS316L for high-temperature (up to 873 K) tribological applications.

A Strongly Reducing sp2 Carbon-Conjugated Covalent Organic Framework Formed by N-Heterocyclic Carbene Dimerization.

Covalent organic frameworks linked by carbon-carbon double bonds (C=C COFs) are an emerging class of crystalline, porous, and conjugated polymeric materials with potential applications in organic electronics, photocatalysis, and energy storage. Despite the rapidly growing interest in sp2 carbon-conjugated COFs, only a small number of closely related condensation reactions have been successfully employed for their synthesis to date. Herein, we report the first example of a C=C COF, CORN-COF-1 (CORN = Cornell University), prepared by N-heterocyclic carbene (NHC) dimerization. In-depth characterization reveals that CORN-COF-1 possesses a two-dimensional layered structure and hexagonal guest-accessible pores decorated with a high density of strongly reducing tetraazafulvalene linkages. Exposure of CORN-COF-1 to tetracyanoethylene (TCNE, E1/2 = 0.13 V and -0.87 V vs. SCE) oxidizes the COF and encapsulates the radical anion TCNE•- and the dianion TCNE2- as guest molecules, as confirmed by spectroscopic and magnetic analysis. Notably, the reactive TCNE•- radical anion, which generally dimerizes in the solid state, is uniquely stabilized within the pores of CORN-COF-1. Overall, our findings broaden the toolbox of reactions available for the synthesis of redox-active C=C COFs, paving the way for the design of novel materials.

Use of carbon-encapsulated zero-valent iron nanoparticles from waste biomass to hydrogen sulphide wet removal.

This study evaluates the use of carbon-encapsulated zero-valent iron nanoparticles for biogas upgrading in wet systems. The nanoparticles were produced by hydrothermal carbonization, using olive mill waste (OMW) or microalgae as carbon sources. The solids were characterized to investigate the specific surface area, total and zero-valent iron content, pHPZC and chemical and crystalline composition. Their adsorption performance towards hydrogen sulphide (H2S) was tested by treating two types of synthetic biogas with and without CO2. In both cases, the starting H2S concentration was approximately 60 ppm and the experiments lasted until the complete saturation of the nanoparticles. Optimal Fe/C ratios of 0.05 for OMW nanoparticles and 0.2 for microalgae nanoparticles demonstrated H2S-specific adsorption capacities of 9.66 and 9.55 , respectively, in a synthetic biogas without CO2. The addition of CO2 in biogas reduced adsorption, possibly due to system acidification. X-ray photoelectron spectroscopy analysis revealed surface compounds on the surface of the spent nanoparticles, including disulphides, polysulphides and sulphate. The saturated adsorbents were effectively regenerated with air, leading to the oxidation of sulphur species and desorption. The regeneration allowed a total adsorption capacity of 53.25 and 34.14 , after 10 consecutive cycles of adsorption/regeneration with a single batch of olive mill and microalgae nanoparticles, respectively.

Electrospinning and melt electrowriting of a tunable triblock-copolymer composed of poly(ε-caprolactone) and poly(L-lactic acid) for biomedical applications

Both electrospinning (ES) and melt electrowriting (MEW) garner emerging interest within the field of biomedical applications. Poly(ε-caprolactone) (PCL) is still the gold standard for both techniques, demonstrating excellent processability due to its solubility, melt flow properties and thermal stability. However, when evaluating biomaterials for soft tissue applications, PCL exhibits limitations such as low elasticity and extended biodegradation times. Additionally, the limited availability of materials that are processable by MEW constrains their broader clinical translation. To address this limitation, a tunable triblock-copolymer of PCL and poly(L-lactic acid) (PLLA) is synthesized and processed using ES and MEW. This synthesis employs a PCL-diol backbone with a molar mass of 30 000 g mol-1, to which various lengths of PLLA end-blocks are added on both termini (PLLA-b-PCL-b-PLLA). The successful incorporation of these tunable end-blocks is verified through spectroscopic analysis. The ES of PLLA-b-PCL-b-PLLA reveals excellent fiber formation, with fiber diameters ranging between 2–4 µm as the PLLA molar mass increases. The tunable nature of the polymer allows for MEW at 90 °C, producing fibers with diameters ranging between 40–50 µm. Additionally, the materials exhibit adjustable mechanical properties and biodegradation rates by varying the PLLA segment lengths. Finally, in vitro cell testing using MC3T3-E1 cells demonstrates the polymer's excellent biocompatibility.