The hydrogenation of naphtha is critical to producing stable, clean gasoline, yet current catalysts often lack selectivity and stability. In this work, a novel palladium–magnesium oxide (Pd/MgO) nanocatalyst was developed to address these challenges. The catalyst was prepared by reduction of Na2PdCl4 on MgO support using sodium borohydride, resulting in well-dispersed Pd nanoparticles with an average size of 1.7 nm and a Pd loading of 0.9 wt.% (nominally 1 wt.%). The size, composition, and dispersion of the nanoparticles were confirmed using transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, hydrogen pulse chemisorption, inductively coupled plasma atomic emission spectroscopy, and hydrogen temperature programmed reduction measurements. Catalytic tests showed great activity of quinoline hydrogenation at 150 °C and 40 atm H₂, with a corrected turnover frequency (TOFcorr) of 6400 h⁻¹, which was almost fourfold higher than Pd/SiO₂ and Pd/Al₂O₃ commercial catalysts (TOFcorr = 1600-1800 h⁻¹). Linear alkenes were hydrogenated with the catalyst at mild conditions (25 °C and 10 atm H₂). Moreover, during biodiesel upgrading, the conversion of polyunsaturated fatty acid methyl esters to stable monounsaturated products was achieved at (100 °C, 1 atm of H₂ with >80 % conversion). Recyclability tests proved that the alkene hydrogenation activity was stable in three cycles, and only slight deactivation in quinoline hydrogenation occurred. This work shows that the Pd/MgO nanocatalysts are promising for enhancing the quality of gasoline, minimizing the formation of gums, and increasing the stability of biodiesel because of their nanoscale dispersion, high selectivity, and recyclability.
A causal artificial intelligence (AI) model was developed to support the discovery of new superconducting materials by analysing causal relationships between interval-valued elemental descriptors and the superconducting critical temperature, Tc. The aim is to explore a broad elemental composition space without requiring prior knowledge of material structure. Using a University of California, Irvine dataset comprising 21,263 materials with chemical formulae, 81 features, and Tc values were aggregated into temperature-based intervals and analysed within a reproducing kernel Hilbert space framework to infer a causal directed acyclic graph. Three interval features emerged as direct causal drivers of Tc: the standard deviation of mass density, the weighted geometric mean of electron affinity, and the weighted geometric mean of valence. A random forest model using all predictors achieved an R² of approximately 92.9 %, while the causal model, using only these three features, achieved an R² of approximately 89.7 %. Under out-of-distribution splits, the causal model demonstrated superior robustness. Estimated interventional (“do”) effects revealed nonlinear behaviour, and counterfactual analyses of hypothetical interventions further demonstrated the potential of causal AI for guiding exploration of new materials.
Magnesium alloys have attracted considerable attention, particularly in the biomedical field, due to their excellent biocompatibility and bone-like properties, which make them suitable materials for biomedical applications. However, their low corrosion resistance and rapid degradation lead to poor functional performance. Therefore, this review focuses on the biomedical applications of magnesium alloys and examines the corrosion mechanisms and corrosion types affecting these alloys when used in the medical field. Among the many techniques, this review focuses on surface coating preparation. Surface coating techniques have helped increase corrosion resistance and biocompatibility while reducing the susceptibility of magnesium alloys to premature degradation. These coatings represent a modern approach for improving the clinical performance of these alloys. However, several challenges remain, including balancing degradation rates with structural integrity and enhancing their compatibility with biological tissues. Accordingly, this review summarizes recent advances in surface coating technologies and provides an overview of the corrosion mechanisms associated with coated magnesium alloys, thereby highlighting future directions and opportunities for their broader application in the biomedical field.
In the present paper, the potential of a locally sourced plant-based adsorbent, Ziziphus lotus stone, for the removal of Congo Red (CR) dye from aqueous media was evaluated. The adsorbent was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Brunauer-Emmet-Teller (BET) surface area analysis. These combined characterization methods provided a comprehensive profile of the material, confirming the presence of active surface functional groups, a porous structure and high thermal stability. The BET surface area was estimated at 4.7758 m² g–1, with a pore size of 4.3578 nm. About 10 % enhancement in the adsorption efficiency of Congo Red dye was achieved using response surface methodology (RSM) based on the Box-Behnken Design (BBD), considering three key factors: adsorbent dose, pH, and initial CR dye concentration. As a result, the overall adsorption efficiency reached up to 95 %. The isotherm study, based on non-linear isotherm models, indicated that the adsorption data were best described by the Freundlich model, with maximum adsorption capacity Qmax of 11 mg g–1. Thermodynamic analysis revealed negative values of ∆G0, ∆H0 (–11.0959 kJ mol–1), and ∆S0 (–29.587 J K–1 mol–1), indicating that the adsorption process was exothermic, spontaneous, and accompanied by decreased randomness at the solid-liquid interface. Furthermore, a techno-economic assessment of the based-plant adsorbent and the overall adsorption process was conducted. The estimated production cost of the Ziziphus lotus stone adsorbent was estimated at around 0.11304 USD/kg, while the overall adsorption cost was approximately 0.112 USD/m3. These findings confirm the viability and high efficiency of Ziziphus lotus stone as a low-cost adsorbent for large scale and low-cost environmental applications.
This study investigates the low-temperature rheological behavior and wax deposition tendency of high-paraffin blended crude oil in order to improve flow stability during pipeline transportation. The results show that decreasing temperature leads to a significant increase in yield stress and effective viscosity, indicating the formation of a structured paraffin network responsible for reduced flowability. Comparative analysis demonstrated that the Herschel–Bulkley model most accurately describes the non-Newtonian behavior of the system (R² = 0.995). Strong correlations between pour point, yield stress, and consistency index confirm the structural origin of flow resistance and highlight the role of crystallization processes in determining rheological properties. Chemical treatment significantly weakened intermolecular interactions within the paraffin–resin–asphaltene system, reduced wax deposition tendency, and improved flow characteristics. Among the investigated formulations, the composite additive (DHC) exhibited the highest efficiency, promoting partial transition toward near-Newtonian behavior and enhanced low-temperature mobility. The results demonstrate that composite chemical additives provide an effective approach for controlling structure formation and improving transportation properties of high-paraffin crude oils.
This study presents the development and evaluation of a novel ternary BNP corrosion inhibitor composed of boric acid (B-component), 1,4-phenylenediamine (N-component), and disodium hydrogen orthophosphate (P-component) for the protection of D16T aluminum alloy in model formation water. The inhibition performance was evaluated using gravimetric, electrochemical, and surface wettability techniques. The optimized BNP composition achieved a protection efficiency of 93.13 % at 31.2 mg dm–3 and significantly reduced the corrosion current density from 6.41·10–6 to 2.16·10–6 A cm–2. The inhibitor decreased the apparent activation energy and increased surface hydrophobicity, indicating the formation of a protective surface layer. Inhibitor adsorption obeyed the Langmuir and Freundlich isotherms, indicating additional heterogeneous surface interactions, and was characterized as spontaneous and endothermic. Electrochemical results suggested mixed-type inhibition mechanism. The results indicate that cooperative interactions between the B-, N-, and P-components promoted the formation of a stable protective layer, highlighting the potential of multicomponent inhibitor systems for corrosion protection of aluminum alloys in aggressive oilfield environments.
The present study investigated the influence of solvent polarity on the kinetics of microwave-assisted extraction of phenolic compounds from black locust flowers. Extractions were conducted in an open-vessel microwave system operating at 462 W, with a constant liquid-to-solid ratio of 10 mL g–1. Extraction kinetics were simulated using Ponomarev’s model and an unsteady-state diffusion model. Furthermore, the effect of solvent polarity was evaluated with respect to the mineral composition and antiradical activity of the extracts.Among the tested solvents, the 50 % (v/v) ethanolic extract showed the highest total phenolic content (1.94 g gallic acid equivalents/100 g d.m.) and flavonoid content (0.97 g rutin equivalent/100 g d.m.), while simultaneously exhibiting the strongest antiradical activity (half-maximal inhibitory concentration of 0.424 mg mL–1). Correlation analysis indicated that the antiradical activity is not solely attributable to the presence of phenolic compounds, but also to other bioactive compounds present in the extracts. Solvent polarity significantly affected macro- and micro-element content, with potassium identified as the predominant macroelement. The absence of detectable heavy metals, specifically lead and cadmium, confirms the safety profile and suitability of the extracts for further application. The extracts, particularly those obtained using 50 % (v/v) ethanol, demonstrate significant potential as bioactive ingredients for functional product development. These findings support the replacement of synthetic additives with natural alternatives, aligning with the principles of sustainable and green chemistry.
The hydrogenation of naphtha is critical to producing stable, clean gasoline, yet current catalysts often lack selectivity and stability. In this work, a novel palladium-magnesium oxide (Pd/MgO) nanocatalyst was developed to address these challenges. The catalyst was prepared by reduction of Na2PdCl4 on MgO support using sodium borohydride, resulting in well-dispersed Pd nanoparticles with an average size of 1.7 nm and a Pd loading of 0.9 wt.% (nominally 1 wt.%). The size, composition, and dispersion of the nanoparticles were confirmed using transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, hydrogen pulse chemisorption, inductively coupled plasma atomic emission spectroscopy, and hydrogen temperature programmed reduction measurements. Catalytic tests showed great activity of quinoline hydrogenation at 150 degrees C and 40 atm H-2, with a corrected turnover frequency (TOFcorr) of 6400 h(-)& sup1;, which was almost fourfold higher than Pd/SiO2 and Pd/Al2O3 commercial catalysts (TOFcorr = 1600-1800 h(-)& sup1;). Linear alkenes were hydrogenated with the catalyst at mild conditions (25 degrees C and 10 atm H-2). Moreover, during biodiesel upgrading, the conversion of polyunsaturated fatty acid methyl esters to stable monounsaturated products was achieved at (100 degrees C, 1 atm of H-2 with >80 % conversion). Recyclability tests proved that the alkene hydrogenation activity was stable in three cycles, and only slight deactivation in quinoline hydrogenation occurred. This work shows that the Pd/MgO nanocatalysts are promising for enhancing the quality of gasoline, minimizing the formation of gums, and increasing the stability of biodiesel because of their nanoscale dispersion, high selectivity, and recyclability.
An indigenous Aspergillus fumigatus strain was subjected to physical, chemical, and combined mutagenesis to enhance endoglucanase production. Using rice straw as a greater carbon source, maximum activity (84.94 U mL–1) was achieved via 10-minute UV exposure, while 150 µg mL–1 ethyl methane sulphonate (EMS) yielded 62.89 U mL–1. Combined mutagenesis (10 min UV+ 150 µg mL–1 EMS) significantly improved activity to 123.32 U mL–1, a 2.2-fold increase over the wild type. Optimization through response surface methodology (RSM) identified optimal conditions: pH 5.0, 55 °C, 5-day incubation, and 5 mL inoculum. Purified endoglucanase exhibited high affinity for CMC and was further activated by 300 mM CaCl2 to 176.92 U mL–1. Kinetic and characterization studies confirm that this thermophilic, genetically improved (physical, chemical, and combined mutagenesis) strain is highly suitable for industrial applications in textiles and biofuels.
The bioeconomy today relies mostly on sugar and physicochemical extraction processes, which limit both cost reduction and scale-up potential, yet these two aspects are vital for the market success of circular bioeconomy products. Gas fermentation is a platform technology that utilizes all kinds of waste biomass streams through low-cost, clean, and well-defined gaseous substrates. It can be used to obtain bioplastics. In this work, methane (CH4) was subjected to methanotrophic conversion by Methylocystis sp. GB 25. The freeze-dried bacterial biomass containing 47 wt% P(3HB) – poly(3-hydroxybutyrate), was subsequently fed to mealworms. The cells were fully consumed, and the P(3HB) granules were recovered within 24 h. The final PHB purity obtained was 95 % through a simple purification step. This work demonstrated that a simple bioprocess for biopolymer extraction can be applied to small bacterial cells like methanotrophs, offering a viable alternative to classic downstream processing steps such as chlorinated solvent extraction. The methanotrophic PHB was found to exhibit high molecular weight, making it an interesting biobased, biodegradable polymer.
This study explores early formulation parameters influencing hydroxypropyl cellulose (HPC)-based microparticles as carriers for paracetamol, with the aim of establishing a modified-release drug delivery system and informing future design optimization. Microparticles were prepared via the oil-in-oil emulsion/solvent evaporation method using acetone, HPC as a thermo-responsive polymer, and Tween 80 as a non-conventional surfactant. Polymer content and phase ratio were varied to assess effects on encapsulation efficiency and dissolution behavior. Characterization by FTIR, DSC, UV-Vis, laser diffraction, and microscopy confirmed spherical morphologies (495–760 µm), thermal stability, and successful drug encapsulation (up to 73 %). In vitro dissolution at pH 6.8 revealed modified release profiles, with kinetics best described by the Weibull model, indicating Fickian diffusion as the dominant mechanism. Polymer content emerged as the key variable affecting critical quality attributes. These findings provide a foundation for rational formulation and process optimization, to be further refined through D-optimal experimental design.
The increasing concentrations of toxic hexavalent chromium [Cr(VI)] in aquatic systems pose a major threat to human health and the environment, necessitating the development of high-performance, reasonably priced, and environmentally friendly adsorbents. Mesoporous silica nanoparticles (SiNPs) were synthesized from groundnut shell waste via alkaline extraction followed by acid precipitation, yielding 21 %. Amorphous, mesoporous silica with a high surface area (84.61 m2 g-1) and a large number of silanol groups was confirmed by characterization (XRD, FTIR, SEM-EDS, and BET). Batch adsorption experiments revealed that the maximum Cr(VI) removal efficiency reached 92 % at pH 4, with an optimum equilibrium adsorption capacity (qe) of 4.5955 mg g-1. The process followed pseudo-second-order kinetics (R2 = 0.99) and the Freundlich isotherm model (R2 = 0.9826), indicating chemisorption. Surface complexation was confirmed by post-adsorption analyses, demonstrating the effectiveness the SiNPs as environmentally friendly adsorbents for wastewater treatment.
Exothermic reactive processes pose significant safety risks due to the possibility of thermal runaway. Reliable tools for the design, control, and optimization of such systems are therefore essential. Stability analysis provides a powerful framework, but its effectiveness depends on an adequate representation of reactor hydrodynamics. Following the pioneering work of Varma, Morbidelli, and Wu, tubular reactors have mainly been analyzed using ideal plug flow reactor (PFR) models, which may lead to a partial assessment of critical operating regimes. In particular, neglecting non-idealities such as axial dispersion can underestimate runaway risk and distort predicted stability limits. In this work, the impact of non-ideal plug flow behavior on reactor performance and stability is investigated by comparing ideal and axially dispersed PFR models within a sensitivity-based stability analysis (VMWT). The methodology is applied to the design of a multitubular reactor for the liquid-phase oxidation of benzyl alcohol to benzaldehyde. The results show how incorporating axial dispersion yields a more realistic stability picture while preserving computational efficiency, thereby supporting safer and more robust reactor design.
This study investigates the liquid-liquid equilibrium (LLE) behavior of ternary and quaternary systems composed of water, lactic acid, 1-octanol, and salts (NaCl and KCl). Phase behaviour was predicted using the non-random two-liquid (NRTL) model. Accurate thermodynamic modeling is essential for optimizing separation processes in the pharmaceuticals, food, and bio-based chemical industries. Experimental tie-line data were obtained at salt mass fractions from 0 to 15 % and validated with Othmer-Tobias and Hand correlations, which confirmed the high consistency of the data. The NRTL predictions were evaluated using the root mean square deviation (RMSD), yielding low values (0.1418 for 15 % NaCl, 0.1088 for 15 % KCl), demonstrating strong predictive reliability. The salting-out effect was quantified through binary interaction parameters, such as 20.4174 for water-1-octanol (15 % KCl) and 15.5637 for the same pair (15 % NaCl), indicating enhanced lactic acid partitioning into the organic phase. Overall, the results confirm the accuracy of the NRTL model in describing ionic interactions and phase separation, offering a reliable framework for efficient extraction and purification processes.
Accurate determination of enzyme kinetic parameters is critical for model-based design and intensification of biocatalytic processes, particularly in microscale systems. While Michaelis-Menten kinetics provides a foundational framework, its extension to reversible, multi-substrate, and inhibited reactions introduces significant challenges in parameter estimation-most notably, parameter sensitivity and non-uniqueness. This study systematically investigates these challenges across three case studies of increasing complexity: (i) mono-substrate Michaelis-Menten kinetics, (ii) reversible enzymatic reactions with four parameters, and (iii) a six-parameter reversible mono-substrate kinetic model with substrate and product inhibition. In the first two cases, we show that vastly different parameter sets can yield nearly indistinguishable model fits to experimental data, exposing the limitations of classical graphical and nonlinear regression methods. In the mono-substrate case based on real experimental data, two parameter sets differing by nearly two orders of magnitude produce virtually identical model outputs, demonstrating practical non-uniqueness even for simple kinetic models. For the six-parameter inhibited system, a theoretical and numerical analysis reveals intrinsic non-uniqueness of the parameter estimation problem, characterized by an in finite family of parameter vectors yielding identical solutions. These results demonstrate that parameter non-uniqueness is not merely a consequence of experimental noise, but a structural property of complex kinetic models, emphasizing the need for more robust and structurally informed modeling approaches in biocatalysis.
This work examines the effect of Pulicaria odora leaf extract effect as a green inhibitor on SS308 steel corrosion in a 1 mol L–1 hydrochloric acid solution. The electrochemical results reveal that inhibitory efficiency increases with the concentration of Pulicaria odora leaf extract, reaching a maximum inhibition rate of 94.6 % at 500 ppm. Potentiodynamic polarization curves suggest that the plant extract acts as an anodic-type inhibitor. The polarization and electrochemical impedance findings are in good agreement. Adsorption of the inhibitor on the steel surface is spontaneous and follows the Langmuir isotherm. Furthermore, a copper-based catalyst synthesized using Pulicaria odora extract produced a good yield, and this catalyst showed effective photodegradation of methylene blue. The CuO nanoparticles (NPs) synthesized from Pulicaria odora extract showed significant antimicrobial activity against the tested bacterial strains.
This study explores early formulation parameters influencing hydroxypropyl cellu-lose (HPC)-based microparticles as carriers for paracetamol, with the aim of establishing a modified-release drug delivery system and informing future design optimization. Mi-croparticles were prepared via the oil-in-oil emulsion/solvent evaporation method using acetone, HPC as a thermo-responsive polymer, and Tween 80 as a non-conventional sur-factant. Polymer content and phase ratio were varied to assess effects on encapsulation efficiency and dissolution behavior. Characterization by FTIR, DSC, UV-Vis, laser dif-fraction, and microscopy confirmed spherical morphologies (495-760 mu m), thermal stability, and successful drug encapsulation (up to 73 %). In vitro dissolution at pH 6.8 revealed modified release profiles, with kinetics best described by the Weibull model, indicating Fickian diffusion as the dominant mechanism. Polymer content emerged as the key variable affecting critical quality attributes. These findings provide a foundation for rational formulation and process optimization, to be further refined through D-optimal experimental design.
An agitation impeller with shrouded blades—specifically, a closed impeller—was redesigned. A closed impeller originating from a conventional turbine-type impeller was analyzed by considering the internal liquid flow characteristics. As a result, an impeller consisting of six flat blades with radially tapered widths was developed for closed-mode operation. The modified closed impeller (6RTW-FCI) was applied to gas-liquid agitation. The flow behavior of the gas-liquid mixture in the impeller region was examined with energy considerations based on the impeller power characteristics in the gassed liquid. The internal cavities of the 6RTW-FCI generated gas bubbles that moved radially out ward due to the accelerated liquid flow produced by the impeller. The power characteristics of the 6RTW-FCI in terms of relative power consumption, which was with no sudden change for various aeration-agitation rates, supported energy conversion through the impeller, resulting in favorable gas-liquid dispersion.
The bioeconomy today relies mostly on sugar and physicochemical extraction processes, which limit both cost reduction and scale-up potential, yet these two aspects are vital for the market success of circular bioeconomy products. Gas fermentation is a platform technology that utilizes all kinds of waste biomass streams through low-cost, clean, and well-defined gaseous substrates. It can be used to obtain bioplastics. In this work, methane (CH4) was subjected to methanotrophic conversion by Methylocystis sp. GB 25. The freeze-dried bacterial biomass containing 47 wt% P(3I1B) - poly(3-hydroxybutyrate), was subsequently fed to mealworms. The cells were fully consumed, and the P(3HB) granules were recovered within 24 h. The fmal PHB purity obtained was 95 % through a simple purification step. This work demonstrated that a simple bioprocess for biopolymer extraction can be applied to small bacterial cells like methanotrophs, offering a viable alternative to classic downstream processing steps such as chlorinated solvent extraction. The methanotrophic PHB was found to exhibit high molecular weight, making it an interesting biobased, biodegradable polymer.
Coagulation is a critical step in water treatment, with polyaluminum chloride being a commonly used coagulant. Its main mechanisms are charge neutralization and sweep coagulation. Minimizing sweep coagulation, when appropriate, can reduce chemical use and improve sludge management. A Fuzzy Inference System (FIS) is an effective tool for handling uncertainties and is often used for simplified process modeling. In this study, a FIS was developed to estimate the contribution of the sweep mechanism using zeta potential, insoluble aluminum content, and turbidity removal as inputs. The model used three input variables and nine rules, aiming for low computational demand. The highest estimated sweep contribution occurred at pH slightly basic and Al(s) concentration > 2 mg L⁻1 in a natural low-turbidity water sample. The FIS enabled the integration of frequent measured variables into a single numerical output estimation linked to coagulation mechanisms, supporting decision-making and enabling opportunities for automation and cost reduction.
