Chemistry and Materials Science

Abstract: Thermophilic microbial electrolysis cells (MECs) may couple wastewater valorization with hydrogen production, but the microbial dynamics influencing their performance remain poorly understood. This study investigated microbial succession and biofilm development in a single-chamber MEC operated for 132 days at 55 °C with fermented sugarcane vinasse under 0.8, 0.9, and 1.1 V. Hydrogen production and microbial colonization were evaluated by gas analysis, scanning electron microscopy, and 16S rRNA gene amplicon sequencing of suspended and electrode-associated biomass. At 0.8 V, hydrogen accounted for 94.7% of the gas phase with a surface-area-normalized H₂ production rate of 30.4 L H₂ m⁻² d⁻¹. During operation at 1.1 V, these parameters reached 96% and 55.4 L H₂ m⁻² d⁻¹. Microscopy confirmed colonization of the carbon-felt anode at the end of operation. The community underwent marked succession: Akkermansia and Pseudomonas were transiently enriched, Caldanaerobius dominated at 0.8 V, and Moorella predominated at the final stage, representing 41.4% of the suspended and 44.9% of the electrode-associated communities. Thermoanaerobacterium increased from 8.1% in suspended biomass to 18.4% on the electrode. These results demonstrate that long-term thermophilic operation selected a specialized consortium comprising fermentative, acetogenic, and potentially electrode-interacting populations while supporting high-rate hydrogen production from fermented vinasse.

Abstract: Transition metal catalyzed olefin coordination polymerization is the key technology for production of polyolefin (high-density polyethylene, isotactic polypropylene etc.); the slurry polymerization process has been employed in terms of better mass transport and temperature controls. In this study, ethylene slurry polymerizations by Cp*TiCl2(O-2,6-iPr2-4-R-C6H2) [Cp* = C5Me5; R = H (1), SiEt3 (2)] were studied in the presence of poly(methylaluminoxane) support cocatalyst (sMAO). These polymerizations conducted at 25–70 ºC gave spherical polyethylene particles without formation of fluffy PE materials irrespective of the amount of catalyst and/or sMAO loadings, strongly suggest that sMAO plays a role as a template for the particle growing with control of the shape during the polymerization event (called replica effect). The activities at 70 ºC by 2 showed higher than 1, and the yields in the polymerization by 1–sMAO catalyst system increased over time course.

Abstract: Re-entrant structures can be configured into linear mechanical systems that combine the dynamics of unidirectional motion with structural stiffness. Linear technology is defined as a subset of drive and control engineering designed to handle cyclic dynamic loads—including the damping of mechanical vibrations—with high energy efficiency. Transient, repetitive loads are utilized to achieve precise positional changes, ensuring high performance and accuracy. By assembling individual re-entrant unit cells into columns, rigid systems can be created that expand precisely in the perpendicular direction when subjected to tension; the longitudinal and transverse displacements are linked by a negative Poisson's ratio. Such structures are suitable for generating linear mechanical motion along a straight path. The study investigated two versions of re-entrant linear structures designed and fabricated from metal: one based on interconnected torsion springs and another composed of struts connected via hinges to a single extension spring, equipped with guides. The spring-like nature of the structures ensured reversible behavior during stretching and unloading cycles. An effective Young's modulus was estimated based on experimental force-elongation relationships, and negative Poisson's ratio values were determined from measurements of elongation during stretching. The study demonstrated the feasibility of manufacturing linear auxetic structures using assembly techniques, highlighting their potential for engineering applications.

Abstract: Cysteine-stabilised silver nanoparticles (cys-AgNPs) were prepared in a one-pot aqueous synthesis in which AgNO₃ was reduced with NaBH₄ and the particles were capped with cysteine at room temperature. Formation of the particles was indicated by a colour change from colourless to yellow and then reddish-brown, with a localised surface plasmon resonance (LSPR) band at 401 nm that changed little over 100 min. UV-vis, FTIR, TGA, CHNS microanalysis, powder XRD, SEM and TEM were used for characterisation. These techniques indicated crystalline face-centred cubic silver of about 5–48 nm with a bimodal size distribution. They also showed a substantial organic fraction (about 40–53 wt%), with cysteine probably bound to the silver surface through the thiol group. Addition of Cu(II), Ni(II) and Au(III) (2–20 ppm) caused a rapid colour change and a marked decrease and shift of the LSPR band within 5 min. Batch experiments with Cu(II) and Ni(II) examined the effects of initial concentration, contact time, adsorbent dose, pH and temperature. Uptake reached about 10 mg g⁻¹ at 20 ppm, was fast (Cu(II) near-complete within 5 min), followed pseudo-second-order kinetics and was best described by the Henry isotherm. Ni(II) uptake increased with temperature and with pH. These results show that cys-AgNPs can bind Cu(II) and Ni(II) rapidly from dilute solution and are a candidate material for combined colorimetric sensing and removal of heavy metals. Selectivity, working capacity and performance in real wastewater still need to be established.

Abstract: A long-term stability study of a manufactured substance, material, or object (a product) is a known task in analytical chemistry (testing) laboratories serving applied science, industry and trade. It is also an important part of development of reference materials as measurement standards. The main outcome of a long-term stability study is a conformity decision at the point on the time scale when the product property value is expected to violate its tolerance/specification limit. The period of time (the interval on the time scale) from the product fabrication up to this ‘tipping point’, determined with the specified confidence probability, is recognized as the product shelf life or lifetime. After the tipping point, the product is deemed unfit for its intended use. Using a Bayesian approach, the present position paper (a perspective) considers tipping point analysis as a statistical tool to estimate the shelf life of a substance, material, or object, taking into account risks of false decisions in its conformity assessment.

Abstract: This study presents results from comprehensive investigations of scapolite samples exhibiting natural or thermally induced photoluminescence. A range of analytical techniques, including single-crystal X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, photoluminescence spectroscopy and electron paramagnetic resonance spectroscopy was employed to characterize sulphur-related defect centers within the scapolite anionic cages. Differential scanning calorimetry combined with thermogravimetry and mass spectrometry was used to analyze the stages of degassing and quantify the volatile components. A new interpretation of the electron density distribution within the scapolite anionic cage has been proposed. This enables the localization of possible precursors of S2•- radicals, the later acting as luminescent centers. Key parameters, including atomic positions, occupancies, and bond lengths, were determined for the newly observed moieties. Furthermore, a novel methodology approach was developed to quantify SO42- and CO32- ratios in the structure based on the occupancy of their oxygen sites. Finally, the conditions necessary for the formation of persistent S2•- radicals in fluorescent scapolites were discussed, with an emphasis on the required cationic environment and charge-transfer conditions.

Abstract: Focusing on the evolution of anti-armor threats and material responses, this review traces the development of tank armor materials from rolled homogeneous armor steel to metal, ceramic, polymer-composite systems, and reactive protective structures. For kinetic projectiles, shaped-charge jets, long-rod penetrators, and top-attack threats, the response mechanisms and application boundaries of high-hardness steels, lightweight alloys, ceramic/fiber composite armor, confined ceramic-metal laminates, explosive reactive armor, and porous, slat, and bio-inspired structures are compared. Material-structure coupled mechanisms including adiabatic shear, impedance matching, and ceramic fracture are summarized. The reviewed literature indicates that armor design is shifting from single-property optimization toward coordinated trade-offs among hardness, toughness, density, spatial configuration, and system interfaces. Functionally graded materials, micro-laminated composites, damage-sensing interfaces, and materials informatics offer possible routes for lightweight design, multi-hit resistance, and maintainability. However, cross-material comparison remains constrained by differences in projectile type, impact velocity, angle of incidence, boundary conditions, and evaluation criteria. Engineering feasibility still requires validation through unified databases, multi-hit tests, environmental durability studies, manufacturing consistency assessment, and cost analysis.

Abstract: Developing effective collectors for the flotation separation of sulfide minerals is of interest for enhancing the recovery of valuable components from mineral raw materials. This study investigates the flotation properties and surface interactions of a multicomponent xanthate (MX) collector derived from fusel oil. The composition of the starting fusel oil was determined via GC-MS, while the resulting MX was characterized using ¹H and ¹³C NMR and FTIR spectroscopy. The flotation activity of MX was evaluated using chalcopyrite, galena, sphalerite, and pyrite across three size fractions (−0.100+0.074, −0.074+0.040, and −0.040+0 mm) at collector concentrations of 2, 5, and 7.5 mg/L. Additionally, contact angle measurements, zeta-potential analysis, FTIR, and XPS were employed to assess the interaction between the collector and the mineral surface. It was found that the flotation efficiency of MX depends on the mineral type, particle size, and collector concentration. The highest chalcopyrite recovery (81.9%) was achieved with the −0.074+0.040 mm fraction at an MX concentration of 7.5 mg/L after 3 minutes of flotation. Maximum final recovery values for galena, sphalerite, and pyrite were 73.9%, 51.4%, and 23.9%, respectively. The results demonstrate that the multicomponent composition of MX provides mineral-specific flotation performance, making it a promising candidate for further research in the beneficiation of sulfide mineral ores.

Abstract: Four new derivatives of bioactive natural carnosic acid were obtained during a planned project of target synthesis starting from readily available natural products. In this work, we describe the synthesis of methyl 11,12-di-O-methyl-14-acetylcarnosate and methyl 11,12-di-O-methyl-14-formylcarnosate from methyl 11,12-di-O-methylcarnosate, which was obtained from commercial carnosic acid, by Friedel-Crafts acylation and formylation, respectively. Despite the low yield of the acylation reaction, 17% (56% brsm) yield, alternative formylation worked well which followed by Grignard addition and oxidation increased to 53% the overall yield of the 14-acetyl derivative. Subsequent selective 11-O-demethylation at low temperature afforded in high yield the corresponding hydroxy derivatives. The structure assignment of the newly synthesized compounds was established by ¹H and ¹³C NMR, 2D-NMR and mass spectrometry. The proximity of the acetyl group at C14 to the characteristic isopropyl group of abietane-type diterpenes at C13 resulted in unusual signals in the ¹H and ¹³C NMR spectra. These four novel compounds were screened in a panel of tumor cell lines and basic structure-activity relationships were deduced. They showed improved antiproliferative activity in comparison with natural carnosic acid, even in the low micromolar range for certain cells.

Abstract: Resveratrol is a phenolic compound with recognized antioxidant activity; however, its application is limited by its low stability and poor gastrointestinal bioavailability. This study investigated the functionalization of zein with resveratrol through a free radical-mediated grafting reaction using an ascorbic acid/hydrogen peroxide redox system and evaluated the effect of dialysis on the resulting conjugates. The materials were characterized by UV–Vis, FTIR, XPS, XRD, SEM, DSC, and TGA. Protein and total phenolic contents were determined using the Bradford and Folin–Ciocalteu assays, antioxidant activity was evaluated by ABTS and DPPH, and stability was assessed under simulated gastrointestinal digestion. Spectroscopic, structural, morphological, and thermal analyses indicated modifications in the zein matrix after functionalization, with dialysis producing a more homogeneous surface morphology. The functionalized materials exhibited significantly higher antioxidant activity than native zein, reaching ABTS and DPPH inhibition values of 87–93% and 84–86%, respectively, comparable to free resveratrol. During simulated gastrointestinal digestion, the conjugates maintained resveratrol contents between 885.9 and 1115.0 μmol GAE/g, although significant time-dependent variations were detected within each treatment (p < 0.05). Overall, free radical-mediated functionalization provided zein–resveratrol conjugates with improved physicochemical stability while preserving the antioxidant properties of resveratrol, supporting their potential application as protein-based delivery systems for phenolic bioactive compounds.

Abstract: Coconut shell (CS), an abundant by-product of the coconut-processing industry, is a lignin-rich feedstock for renewable aromatic materials. In this study, H₂SO₄-assisted ethanosolv fractionation of extractive-free CS was optimized using a four-factor Box–Behnken design (ethanol 50–90% v/v, H2_SO₄ 0.2–2.0% w/w, 100–190 °C, 15–90 min). Crude lignin yield (0.2^–11.2%) was governed mainly by temperature and time, whereas total phenolic content (TPC; 284.7–827.2 mg GAE g⁻¹) depended on the ethanol and acid concentrations and their interactions with time. Coconut shell lignin obtained at 70% ethanol, 1.1% H₂SO₄, 190 °C and 90 min (CSL; 11.1% yield) was characterized using commercial alkali lignin (AlkL) as a benchmark. CSL contained 88.0% Klason lignin, 7.8% residual carbohydrate (mainly xylan) and 1.0% ash, and showed a lower sulfur content than AlkL (0.6 vs. 2.5 wt%, EDX) without the crystalline sodium sulfate detected in AlkL. 2D HSQC NMR revealed that CSL is a p-hydroxybenzoate–guaiacyl–syringyl lignin that retains β-O-4′ aryl ether linkages, whereas AlkL is a guaiacyl-type lignin largely depleted of β-O-4′ units. Although its TPC was lower (328.0 vs. 380.1 mg GAE g⁻¹), CSL scavenged ABTS and DPPH radicals about twice as effectively as AlkL (IC50 0.72 and 1.19 vs. 1.47 and 2.94 mg mL⁻¹) and absorbed 4.0- and 3.7-fold more UVB and UVA radiation. H₂SO₄-assisted ethanosolv fractionation therefore yields a low-sulfur, less-condensed lignin with promising antioxidant and UV-absorbing functionality.

Abstract: The increasing concentration of atmospheric CO₂ has intensified the search for sustainable technologies capable of converting this greenhouse gas into valuable fuels and chemicals. Among the available approaches, thermocatalytic, photocatalytic, and electrochemical CO₂ reduction have emerged as key strategies for carbon valorisation. In this regard, biochar-derived materials have recently attracted growing attention due to their renewable origin, tunable porosity, rich surface chemistry, and ability to support active catalytic sites. These properties enhance CO₂ adsorption, activation, and charge-transfer processes, making biochar a promising platform across multiple CO₂ reduction pathways. This review provides a critical overview of recent advances in thermocatalytic, photocatalytic, and electrochemical CO₂ reduction using biochar-based materials, highlighting the relationship between material properties and catalytic performance. Particular attention is given to integrated capture-conversion systems, where biochar enables the coupling of CO₂ adsorption and catalytic transformation within a single material architecture. Current challenges and future research directions are discussed to support the development of scalable biochar-based technologies for sustainable carbon utilisation.

Abstract: Vapor-responsive phosphorescent materials are desirable for sensing, yet reversible switching in Cu(I) complexes remains challenging. Here, a series of ionic and neutral Cu(I)–Imphen–diphosphine complexes were designed and synthesized to enable reversible phosphorescence switching upon exposure to NH₃ and HCl vapors. The complexes were characterized by IR, NMR, X-ray single-crystal diffraction, and ESI-MS. Photophysical studies revealed that absorption and emission are governed by both ligand deprotonation and solvent effects: in dichloromethane, ionic and neutral complexes show markedly different spectral profiles, whereas in DMSO, strong solvation and hydrogen-bond acceptance smooth the spectral differences between ionic and neutral complexes. Notably, when deposited on silica gel TLC plates, complexes 1a and 1b display reversible, visually detectable phosphorescence switching upon alternating exposure to NH₃ and HCl vapors. This response is attributed to reversible protonation/deprotonation, which modulates high-frequency vibrational quenching channels and the extent of π-conjugation, with additional influence from the confined silica gel microenvironment and heat-assisted volatilization of DMSO-d₆ during fuming. This work provides a robust foundation for developing Cu(I)-based materials for reversible acid–base vapor phosphorescent sensing.

Abstract: Gum rosin (GR) is a natural and renewable polymer resin obtained from pine trees with potential in medication delivery applications. This work uses electrospraying to obtain and characterize GR microspheres (eGR) containing zinc phthalocyanine (ZnPc), a synthetic blue-green macrocyclic chemical with photosensitive properties. Electrospraying effectively created uniform microspheres with high encapsulation efficiency. A ZnPc release profile was performed and it was observed that it was quickly evolved during the first 24 hours, reaching 0.438 mg per 100 mg of sample and peaking at 0.868 mg per 100 mg after 72 hours, with a further release rate slowdown, likely due to particle aggregation, gradually declining over several days. Nuclear magnetic resonance (NMR) analysis demonstrated the interaction between ZnPc and GR, confirming the successful microspheres formation. Zeta potential analysis indicated that both, eGR and eGR-ZnPc microspheres had negatively charged surfaces, likely due to anion adsorption or the presence of functional groups. The initial zeta potential values were -80.6 ± 3.3 mV for eGR and -74.1 ± 5.6 mV for eGR-ZnPc reflecting the high stability of microspheres. However, stability decreased after 120 hours due to particle aggregation, with a 70% drop in zeta potential after 360 hours. No significant differences were observed between formulations during stability tests.

Abstract: The development of efficient visible-light-responsive photocatalysts is essential for the sustainable remediation of water contaminated with persistent organic pollutants. In this work, BiAlO₃ perovskite was investigated as a pristine photocatalyst for the first time for the visible-light-driven degradation of Rhodamine B (RhB). The synthesized material exhibited a well-crystallized rhombohedral perovskite structure, while electron microscopy revealed irregularly aggregated particles composed of nanoscale structural features. Surface chemical analysis confirmed the presence of Bi³⁺, Al³⁺, and oxygen species. Optical characterization revealed an optical band gap of approximately 2.7 eV, together with pronounced energy-dependent dielectric, conductivity, and charge-relaxation responses, indicating favorable light–matter and charge-dynamic characteristics. Under visible-light irradiation, BiAlO₃ achieved 87.54% RhB degradation within 90 min, compared with only 9.63% removal by direct photolysis, demonstrating its intrinsic photocatalytic activity. Scavenger experiments revealed that photogenerated holes and hydroxyl radicals make the dominant contributions to RhB degradation, followed by photogenerated electrons and superoxide radicals, with an approximate contribution order of h⁺ > •OH > e⁻ > •O₂⁻. The photocatalyst also retained approximately 75% degradation efficiency after six consecutive cycles, demonstrating good operational stability and reusability. The combination of a relatively narrow band gap, favorable optical and charge-dynamic characteristics, efficient visible-light photocatalytic activity, and satisfactory cycling stability highlights BiAlO₃ as a promising lead-free perovskite photocatalyst for organic pollutant remediation. More broadly, this work establishes the previously unexplored BiAlO₃/RhB photocatalytic system and provides new insight into the relationship between the intrinsic optical and charge-dynamic properties of BiAlO₃ and its photocatalytic performance.

Abstract: This study presents the development and characterization of a polymer-immobilized silver nanoparticle (AgNP) composite for potential application in water remediation and metal recycling. AgNPs were synthesized by ultrasonic spray pyrolysis (USP) using silver nitrate as a precursor and polyvinylpyrrolidone (PVP) as a stabilizing agent, followed by incorporation into a sodium alginate matrix to form separable alginate/AgNP beads. The nanoparticles were characterized by scanning and transmission electron microscopy (SEM, TEM), energy-dispersive X-ray spectroscopy (EDS), selected-area electron diffraction (SAED), dynamic light scattering (DLS), and zeta-potential measurements. The AgNPs were predominantly spherical and crystalline, with a TEM observed average diameter of approximately 90 nm and most particles between 50 and 125 nm. A PVP surface layer of up to approximately 10 nm was observed. DLS measurements showed a hydrodynamic diameter of 159.6 nm. AgNP incorporation into the alginate matrix was confirmed by microscopy and elemental analysis. AgCl formation inside parts of the composite was observed, indicating chemical transformation of silver and the possibility of affected stability and performance due to interactions with the surrounding environment. The dried composite exhibited a low specific surface area of 0.05 m²/g and a pore size of approximately 2 nm, indicating limited accessible porosity. Results indicate a required further optimization of AgNP loading and alginate structure, with preliminary tests of microplastic (MP) interactions with alginate/AgNP beads showing a limited interaction under the tested conditions. The developed composite provides a basis for multifunctional water treatment materials targeting microbial, metallic, organic, and MP contaminants and subsequent metal recycling.

Abstract: Archaeochemical investigations of organic residues have significantly advanced the reconstruction of ancient lifeways by providing molecular evidence of subsistence strategies, ritual behavior, technological practices, and socio-symbolic systems. This study presents a systematic review of archaeochemical scholarship published between 2010 and 2024, synthesizing empirical findings from forty-five peer-reviewed studies retrieved from Scopus, Web of Science, and Google Scholar. Guided by PRISMA 2020 protocols, the review evaluates archaeological materials analyzed, analytical techniques employed, residue categories identified, and interpretive frameworks linking biomolecular signatures to cultural memory and religious practice. The findings demonstrate the methodological dominance of chromatographic and spectrometric approaches, particularly gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry, isotope ratio mass spectrometry, and spectroscopic screening techniques. Lipid biomarkers remain foundational for reconstructing subsistence systems and dietary transitions, while increasing use of proteomic and isotopic analyses has expanded interpretive capacity toward ritual consumption practices, technological knowledge transmission, and spatial organization of domestic activities. Organic compounds such as fatty acids, fermentation markers, terpenoids, nicotine alkaloids, and resinous substances emerge as key proxies for interpreting culinary traditions, ceremonial behavior, and symbolic technological practices. The review highlights a disciplinary shift toward multi-proxy analytical integration and micro-contextual approaches that enhance the reliability of cultural reconstruction. The synthesis suggests that organic residues may be interpreted as biochemical indicators of repeated cultural practices preserved within archaeological materials. Future research directions include the development of comparative residue databases, high-resolution analytical techniques, and interdisciplinary collaboration to support more holistic reconstructions of ancient socio-cultural systems.

Abstract: Ranges of 5 values for 4 different process parameters in a rankine cycle (heater outlet temperature, turbine outlet pressure, pump outlet pressure, and turbine efficiency) were simulatively experimented with in DWSIM software (an open-source process simulation environment used to model and simulate chemical engineering processes under steady-state and dynamic conditions). These values were changed and three dependent variables were measured for each change: net power output, vapor molar fraction and thermal efficiency. Additionally, sensitivity coefficients to measure deviations for each variable were compared according to a set baseline. It was found that the changes in turbine efficiency directly correlated to most of the dependent variables in a linear relationship, while pump outlet pressure and turbine outlet pressure displayed quadratic relationships with the dependent variables. Heater outlet temperature displayed low sensitivity with thermal efficiency, and all such trends are noted in the article. The results provide insight into key operating parameters in Rankine cycles and how theoretical models display the changes in process efficiency. The results were simulated theoretically using a software, which does not necessarily provide output to realistic situations of Rankine cycles. The explicit values of theoretical calculations may not be present in realistic settings, however the general trends and sensitivity coefficients of each parameter and its dependent variable may help provide insight into changes in Rankine operating parameters.

Abstract: Three chiral 1,2-diamines were successfully synthesized from readily available (R)-2-phenyl-2-(piperidin-1-yl)ethan-1-ol. The reaction proceeded through the regioselective ring opening of a common N,N-dialkylaziridinium ion by weakly nucleophilic anilines. The structures of newly synthesized diamines were confirmed by ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and high-resolution mass spectrometry (HRMS). Anticancer activity assays of the synthesized compounds are currently underway.

Abstract: The arc-PVD Ti–Cr–Mo–Ni–N coatings on HG20, HS123, HV420 carbide alloys and C80W1 tool steel, while having approximately the same elemental and phase compositions, differ in morphology, macrostructure, and level of macrostresses. When deposited on steel, the coating exhibits macrolayering, a more extended coating–substrate transition zone, and develops tensile macrostresses, in contrast to the coatings on carbide alloys, which develop compressive macrostresses. The behaviour can be explained by the overheating of the coating during deposition, which results from ion bombardment and is more pronounced on steel due to its poorer thermal diffusivity relative to carbide alloys. The CLTE difference between steel and the coating is significantly larger than that between the carbides and the coating, further contributing to the effect. It was found that, considering these features, the Ti–Cr–Mo–Ni–N coating on steel exhibits lower hardness (~20.3GPa), lower adhesion strength to the substrate (Lc3≈30N, the indenter load at scratch testing corresponding to the onset of coating wear), and a higher wear intensity at room temperature and 500°C (49.80 and 74.20·10−6 mm3·N−1·m−1, respectively), as compared with the hardness values of 25.1–21.7GPa, Lc3≈100N, and wear intensity (corresponding to the absence of a visible wear crater) for the Ti–Cr–Mo–Ni–N coatings on the aforementioned carbide alloys.