Search Results (189)

This study investigates the synergistic modification of cement–soil using waste brick powder (WBP) and polyvinyl alcohol (PVA) fibers to address the growing demand for sustainable construction materials and recycling of demolition waste. An orthogonal experimental design was employed with 5% WBP (by mass) and PVA fiber content (0–1%), evaluating mechanical properties based on unconfined compressive strength (UCS) and splitting tensile strength (STS) and microstructure via scanning electron microscopy (SEM) across 3–28 days of curing. The results demonstrate that 0.75% PVA optimizes performance, enhancing UCS by 28.3% (6.87 MPa) and STS by 34.6% (0.93 MPa) at 28 days compared to unmodified cement–soil. SEM analysis revealed that PVA fibers bridged microcracks, suppressing propagation, while WBP triggered pozzolanic reactions to densify the matrix. This dual mechanism concurrently improves mechanical durability and valorizes construction waste, offering a pathway to reduce reliance on virgin materials. This study establishes empirically validated mix ratios for eco-efficient cement–soil composites, advancing scalable solutions for low-carbon geotechnical applications. By aligning material innovation with circular economy principles, this work directly supports global de-carbonization targets in the construction sector. Full article

The global obesity and metabolic syndrome epidemic have accelerated demand for reduced-sugar food, prompting the food industry to adopt functional sugar alcohols as sucrose substitutes. Threitol is a four-carbon sugar alcohol and an isomer of erythritol. However, there is a scarcity of studies reporting on the edible safety of threitol. This study assessed threitol’s toxicological and metabolic properties. Acute oral administration (10 g/kg) caused no mortality or abnormalities in mice. Repeated 28-day exposure revealed no behavioral or histopathological alterations, with negative outcomes in three genotoxicity tests. Metabolic studies in rats demonstrated that the majority of ingested threitol is excreted in the urine within 24 h. Sensory evaluation indicated threitol’s sweetness equivalence to sucrose, exceeding erythritol and allulose. Notably, 16S rRNA sequencing revealed gut microbiota modulation in threitol-fed mice, indicating potential intestinal health benefits. These integrated findings establish threitol’s preclinical safety and support its development as a novel low-calorie sweetener. Full article

Achieving carbon neutrality requires not only reducing CO₂ emissions but also capturing atmospheric CO₂. Direct air capture (DAC) using amine-based adsorbents has emerged as a promising approach. In this study, we developed amine-epoxy/poly(vinyl alcohol) (AE/PVA) nanofibers via electrospinning and in situ thermal polymerization. PVA was incorporated to enhance spinnability, and B-staging of AE enabled fiber formation without inline heating. We systematically investigated the effects of electrospinning parameters, epoxy-to-amine ratios (E/A), and the degree of PVA saponification on CO₂ adsorption performance. Thinner fibers, obtained by adjusting spinning conditions, exhibited faster adsorption kinetics due to increased surface area. Varying the E/A revealed a trade-off between adsorption capacity and low-temperature desorption efficiency, with secondary amines offering a balanced performance. Additionally, highly saponified PVA improved thermal durability by minimizing side reactions with amines. These findings highlight the importance of optimizing fiber morphology, chemical composition, and polymer properties to enhance the performance and stability of AE/PVA nanofibers for DAC applications. Full article

The persistent contamination of aquatic environments by heavy metals, particularly Pb²⁺, Cd²⁺, and Cu^2+, poses a serious global threat due to their toxicity, persistence, and bioaccumulative behavior. In response, low-cost and eco-friendly adsorbents are being explored, among which CaCO₃-based biocomposites derived from mollusk shells have shown exceptional performance. In this study, a hybrid biocomposite composed of poly(vinyl alcohol) (PVA) and oyster shell-derived CaCO₃ was computationally investigated using Density Functional Theory (DFT) to elucidate the electronic and structural basis for its high metal-removal efficiency. Calculations were performed at the B3LYP/6-311++G(d,p), M05-2X/6-311+G(d,p), and M06-2X/6-311++G(d,p) levels using GAUSSIAN 16. Among them, B3LYP was identified as the most balanced in terms of accuracy and computational cost. The hybridization with CaCO₃ reduced the HOMO-LUMO gap by 20% and doubled the dipole moment (7.65 Debye), increasing the composite’s polarity and reactivity. Upon chelation with metal ions, the gap further dropped to as low as 0.029 eV (Cd²⁺), while the dipole moment rose to 17.06 Debye (Pb²⁺), signaling enhanced charge separation and stronger electrostatic interactions. Electrostatic potential maps revealed high nucleophilicity at carbonate oxygens and reinforced electrophilic fields around the hydrated metal centers, correlating with the affinity trend Cu²⁺ > Cd²⁺ > Pb²⁺. Fukui function analysis indicated a redistribution of reactive sites, with carbonate oxygens acting as ambiphilic centers suitable for multidentate coordination. Natural Bond Orbital (NBO) analysis confirmed the presence of highly nucleophilic lone pairs and weakened bonding orbitals, enabling flexible adsorption dynamics. Furthermore, NCI/RDG analysis highlighted attractive noncovalent interactions with Cu²⁺ and Pb²⁺, while FT-IR simulations demonstrated the formation of hydrogen bonding (O–H···O=C) and Ca²⁺···O coordination bridges between phases. Full article

Using low-cost transition-metal chlorides and furfuryl alcohol as raw materials, the (TiZrHfNbTa)C precursor was prepared, and a three-dimensional braided carbon fiber preform (C/C) coated with pyrolytic carbon (PyC) was used as the reinforcing material. A C/C-(TiZrHfNbTa)C composite was successfully fabricated through the precursor impregnation pyrolysis (PIP) process. Under extreme oxyacetylene ablation conditions (2311 °C/60 s), this composite material demonstrated outstanding ablation resistance, with a mass ablation rate as low as 0.67 mg/s and a linear ablation rate of only 20 μm/s. This excellent performance can be attributed to the dense (HfZr)₆(TaNb)₂O₁₇ oxide layer formed during ablation. This oxide layer not only has an excellent anti-erosion capability but also effectively acts as an oxygen diffusion barrier, thereby significantly suppressing further ablation and oxidation within the matrix. This study provides an innovative strategy for the development of low-cost ultra-high-temperature ceramic precursors and opens up a feasible path for the efficient preparation of C/C-(TiZrHfNbTa)C composites. Full article

The stabilization and upgrading of biomass and waste-derived pyrolysis oils requires development of reliable, active and low-cost upgrading catalysts. Basic natural materials can act as such catalysts and convert reactive oxygenates present in biomass pyrolysis oils. The conversion of furfural as a model compound has been conducted in an autoclave reactor at 200 °C to 300 °C using different calcium-based materials. CaCO₃, Ca(OH)₂, CaO, cement raw meal (CRM) and calcined cement raw meal (cCRM) were screened for their catalytic activity and characterized using X-ray powder diffraction (XRD) and X-ray fluorescence (XRF), nitrogen physisorption, carbon dioxide temperature programmed desorption (CO₂-TPD) and thermogravimetric analysis (TGA). CaCO₃ and CRM had low basicity and showed no catalytic activity at 200 to 300 °C. Notably, 90% conversion of furfural was achieved at 200 °C using Ca(OH)₂ with products being mostly furfural di- and trimers. For the basic CaO and cCRM, a temperature of 250 °C or above caused rapid polymerization of furfural. The proposed mechanism follows the Cannizzaro reaction of furfural, catalyzed by basic sites, polymerization of furfuryl alcohol, decarboxylation of furoic acid and decarbonylation of furfural, releasing CO, CO₂ and H₂O. Calcined cement raw meal showed the most promise for application as low-cost, sacrificial, basic catalyst. Full article

Removing residual energy from end-of-life batteries prior to transportation requires some method of deactivation. While many methods have been proposed, very few have been implemented due to limitations of cost, safety, and efficacy. In this work, multiple cell and battery types (e.g., lithium-polymer pouch cells, 18650 lithium-ion cell, alkaline batteries, and lithium-ion power-tool batteries) were deactivated using a low-cost and easily applied gel consisting of borax cross-linked polyvinyl alcohol and carbon. The PVA–carbon composite creates an external short-circuit pathway of moderate resistance that enables the complete discharge of batteries. Abusive testing conducted after deactivation demonstrates that hazards are largely eliminated, including a complete avoidance of thermal runaway from lithium-ion cells and a reduction in flammable and toxic gases by several orders of magnitude. Full article

Conventional mild hydrotreatment processes of bio-oil present significant challenges of a high degree of polymerization, a low oil yield, high coke formation, and poor catalyst recovery. To address these challenges, the current study looked into investigating and enhancing the properties of raw bio-oil organic phase samples via a solvent-assisted stabilization approach using methanol (METH), ethanol (ETH), isopropyl alcohol (IPA), and ethyl ether (DME). Solvents like methanol (METH) and ethanol (ETH), which are highly polar, yielded higher oil fractions (64% and 62%, respectively) compared to less polar solvents like ethyl ether (DME) at 59%. Isopropyl alcohol (IPA), with intermediate polarity, achieved a balanced oil yield of 63%, indicating its ability to dissolve both polar and non-polar components. Moisture reduction in stabilized bio-oils followed the order IPA > ETH > METH > DME, with IPA showing the highest reduction due to its structural characteristics facilitating dehydration. Viscosity reduction varied, with IPA > ETH > DME > METH. Carbon recovery in stabilized bio-oils ranged from 65% to 75% for DME, ETH, and METH and was 71% for IPA. The heating values of stabilized bio-oils ranged from 28 to 29 MJ/kg, with IPA-stabilized bio-oil showing the highest value (29.05 ± 0.06 MJ/kg). METH demonstrated high efficiency (74.8%) in stabilizing bio-oil, attributed to its strong hydrogen-donating capability. ETH followed closely at 69.5%, indicating its comparable performance in bio-oil stabilization. With moderate efficiency (69.3%), IPA presents a balanced alternative considering its molecular structure and hydrogen solubility. In contrast, DME exhibited lower efficiency (63.6%) due to its weaker hydrogenation capability and propensity for undesired side reactions. The current study suggests that subcritical conditions up to 200 °C are adequate for METH, ETH, and IPA in bio-oil stabilization, comparable to results obtained under supercritical conditions. Full article

Copolymers of N-isopropylacrylamide (NIPA) and alkyl acrylic acids that swell and shrink in response to pH were prepared by dispersion polymerization at 35 °C using N-isopropylacrylamide (transduction monomer), methylenebisacrylamide (crosslinker), 2-dimethoxy-2-phenyl-acetophenone (initiator), N-tert-butylacrylamide (transition temperature modifier), and acrylic acid, methacrylic acid, ethacrylic acid, and propacrylic acid (functional comonomer). The diameter of the microspheres of the copolymer varied between 0.5 µm and 1.0 µm. These microspheres were cast into hydrogel membranes prepared by mixing the pH-sensitive swellable polymer particles with aqueous polyvinyl alcohol solutions followed by crosslinking the polyvinyl alcohol with glutaric dialdehyde for use as pH sensors. Large changes in the turbidity of the polyvinyl alcohol membrane monitored using a Cary 6000 UV–visible absorbance spectrometer were observed as the pH of the buffer solution in contact with the membrane was varied. Polymer swelling was reversible for many of these NIPA-based copolymers. The buffer capacity, ionic strength, pH, and temperature of the buffer solution in contact with the membrane were systematically varied to provide an in-depth pH profile of each copolymer. A unique aspect of this study was the investigation of the response of the NIPA-based polymers to changes in the pH of the solution in contact with the membrane at low buffer concentrations (0.5 mM). The response rate and the reversibility of polymer swelling even at low buffer capacity suggest that NIPA-based copolymers can be coupled to an optical fiber for pH sensing in the environment. We envision using these polymers to monitor rising acidity levels in the ocean due to water that has become enriched in carbon dioxide that endangers shell-building organisms by reducing the amount of carbonate available to them. Full article

This paper seeks to evaluate the effect of reaction parameters on iron electrolysis-catalyzed ozonation (ECO) performance as a promising approach for micropollutant removal. ECO is proposed to be an environmentally and economically suitable technology for the removal of biologically recalcitrant organics in wastewater. In this process, iron ions generated via electrolysis of low-carbon steel react with dissolved ozone to produce hydroxyl radicals. The removal of tert-Butyl alcohol (TBA) was selected as a performance indicator based on its significant resistance to direct ozonation compared to hydroxyl radicals, such that TBA removal denotes catalytic breakdown of ozone. TBA removal was measured with an HS-SPME-GC-MS method for precise quantification. ECO performance ranged from 7 to 77% TBA removal (from 0.73 mM initial concentration), varying depending on the tested levels of initial pH of 5, 7, and 9, applied current between 0.065 and 0.470 A, and ozone supply rate between 3.9 and 6.4 g/h. Performance was generally increased by pH, applied current, and ozone generation, converging at high applied current rates. The most efficient use of ozone was observed at pH 9 and 0.323 A, removing 32.2% of TBA per gram of ozone supplied. Full article

Cement is widely used as an efficient binding agent in concrete; however, the production of cement is the second-largest source of carbon emissions. Therefore, there is an urgent need to explore alternative materials with similar properties. CoRncrete, a corn-based material, shows potential as an eco-friendly substitute. Our previous study showed that oven-dried CoRncrete achieved a maximum compressive strength of 18.9 MPa, which is 37% lower than traditional concrete. Nonetheless, in light of this limitation, CoRncrete still stands as a feasible choice for internal structural applications. This study aims to enhance CoRncrete’s strength by modifying drying conditions and incorporating lightweight thermoplastic polymers as admixtures. Air-drying for 7, 14, 21, and 28 days was tested, with durations of 21 days and greater showing improved internal curing, reduced porosity, and enhanced strength (23.9 MPa). Various high-strength, low-density polymers, including carboxy methyl cellulose (CMC), chitosan (CS), polyvinyl alcohol (PVA), and polyvinylpyrrolidone (PVP), were utilized. PVA demonstrated favorable interactions with cornstarch, also showing improved performance in water durability properties. Air-dried CoRncrete with PVA admixture had maximal water durability properties (up to 20 days) compared to the other samples. Micro-structural analysis revealed reduced porosity in air-dried and polymer-bound samples. Future investigations should extend to an in-depth study on air-drying duration for polymer-bound CoRn-crete and explore novel admixtures to further improve strength and water durability. Full article

Although chitosan (CS) is used in many industries because of its low cost, biodegradability, nontoxic, antibacterial, and antioxidant qualities, it lacks sufficient mechanical and barrier properties. Biodegradable polymers based on CS, polyvinyl alcohol (PVA), and starch (S) were prepared at various ratios (1/3/6 and 1/5/4) via a blending polymerization process in the presence of water as the solvent and glacial acetic acid as the catalyst. The obtained biodegradable polymers were characterized via FTIR, TGA, SEM, and mechanical tests. The biodegradable polymers were mixed with rice straw and carbon black to study the effects of rice straw and carbon black on the physicomechanical properties of the biodegradable polymer films, including viscosity, tensile strength, elongation, and contact angle. The incorporation of rice straw and carbon black into a polymer blend significantly enhanced the physical and mechanical properties while also boosting their biodegradability by 36% and 15%, respectively, due to their biological activity. Notably, the CS/PVA/S blend with a ratio of 1/5/4, combined with rice straw, emerged as the standout performer. It exhibited superior mechanical strength and the shortest degradation time, outperforming the CS/PVA/S blended with a ratio of 1/3/6 mixed with carbon black. According to these findings, the biodegradable polymers became more soluble as the temperature increased from 30 to 45 °C. Full article

Crohn’s disease (CD)’s activation factors are still unclear. However, they are reported to involve an interaction between genetic susceptibility and unhealthy lifestyle factors like smoking, alcohol consumption, low physical activity, low BMI (<18.5 kg/m²), and probably unbalanced nutritional habits. Therefore, the aim of the present review is to demonstrate the possible effects of different nutritional habits, before the occurrence of the disease, as crucial factors for the inception of CD activation. The structure of the present narrative review was conducted following the instructions of the “Review Academy of Nutrition and Dietetics Checklist”. It is well established that the consumption of specific foods and drinks, such as spicy and fatty foods, raw vegetables and fruits, dairy products, carbonated beverages, and coffee or tea, can provoke the exacerbation of CD symptoms. On the other hand, Mediterranean-oriented diets seem to provide an inverse association with the incidence of CD. Moreover, patients seem to have the knowledge to select foods that contribute to the remission of their symptoms. However, it is not clearly reported whether the onset of CD activation is due to lifelong unbalanced nutritional habits and their subsequent effect on gut microbiota secretion, which seems to be the gold standard for CD’s investigation. Therefore, more future studies should record, examine, and compare the nutritional habits between patients with CD (immediately after the disease’s diagnosis) and healthy populations in a lifelong manner, in order to reveal the possible influence of foods on CD onset. Full article

Background/Objectives: The compound (±)-UB006 ((4SR,5SR)-4-(hydroxymethyl)-3-methylene-5-octyldihydrofuran-2(3H)-one) is a promising anti-cancer molecule. The enantiomer (–)-UB006 displays a potent cytotoxic effect in several tumor cell lines, particularly the ovarian cancer OVCAR-3 cell line, with a 40-fold increase in potency compared with the fatty acid synthase (FAS) inhibitor C75. Furthermore, in vivo, (–)-UB006 reduced the tumor burden in neuroblastoma xenografts. This effect was attributed to FAS inhibition and upregulation of apoptotic markers. However, CoA adducts of UB006 presented low solubility. Methods: We synthesized several (±)-UB006 derivatives by elongating the carbon chain of the primary alcohol and/or by adding hydroxyl groups with the aim of finding more potent and soluble anti-cancer compounds. Results: Our results showed a decrease in cytotoxicity when the carbon chain was elongated by more than two carbons. However, ethyl or propyl polyhydroxylated four-branched compounds showed an increased or maintained potency and solubility. The most promising compound was (±)-UB035 (IC50: 2.1 ± 0.2 µM), with a 2.5-fold increase in cytotoxicity in the OVCAR-3 cell line and a >4-fold increase in solubility (>2 mM) compared with (±)-UB006. Full article

This study investigates sub-stoichiometric electron supply, also termed electro-fermentation, to influence product formation in gas fermentation. Two species, Clostridium carboxidivorans and Alkalibaculum bacchi, as well as a co-culture of A. bacchi and Clostridium kluyveri, were tested in batch cultures with and without an external cell potential of 800 mV. The supplied gas mixture was 50:40:10 N₂:H₂:CO₂. The test unit was a single-chamber reactor with a cathode made from an electrically conducting composite of PP and black carbon. The observed current densities were generally very low, around 0.22 mA/m². Despite that, a significant and reproducible change in product patterns and formation rates occurred. C. carboxidivorans increased the formation of acetate (+32%), butyrate (+300% relative to the control), and caproate (+600% relative to the control). In a similar manner, A. bacchi produced more acetate (+38%), butyrate (13 times more than the control), and caproate (only observed in the electrified setup). Additional trials using a modified gas phase composition, 80:20 H₂:CO₂, confirmed the finding that the application of an electric potential enhances chain elongation as well as alcohol formation. Moreover, an experiment with reversed electric polarity showed that a high cathode surface area is essential for inducing metabolic modifications. The results demonstrate that electro-fermentation holds significant potential for improving bioconversion processes aimed at producing green chemicals. Full article