Chemistry and Materials Science

Abstract: The brine of the Aral Sea is considered a complex source of lithium because it contains large amounts of magnesium, potassium, sulfate, and chloride, which prevent the direct preparation of Li₂CO₃. This work describes a technique based on selective precipitation and crystallization of impurities, followed by the isolation of high-purity Li₂CO₃. Initially, magnesium and potassium were precipitated together with Na₂HPO₄ as MgKPO₄, and sulfate was precipitated as CaSO₄·2H₂O using CaCl₂. Such pretreatment made it possible to remove up to 97.1%, 96.3% and 93.4% of magnesium, potassium and sulfate, respectively. Analysis by XRD and EDAX showed that the obtained precipitates consisted of gypsum and phosphate, which can be used as mineral or fertilizer by-products. Then the purified solution was treated with Na₂CO₃ in a stirred crystallizer at 50 °C. Focused Beam Reflectance Measurement (FBRM) analysis showed that increasing the stirring speed from 400 to 600 rpm resulted in smaller Li₂CO₃ particles. The influence of Na2CO3 feed rate was less, but the aggregation of crystals increased at higher concentrations of Na₂CO₃. The proposed technology made it possible to obtain 99.5% pure Li₂CO₃ (for the production of lithium-ion batteries). It was shown that the separation of impurities allows controlling the formation and growth of Li₂CO₃ from natural brine. The developed method provides the opportunity to prepare lithium carbonate suitable for batteries from Aral Sea brine with separation of useful by-products containing magnesium, potassium, calcium, phosphorus and sulfur.

Abstract: Powder mixing is a critical step in pharmaceutical manufacturing, as the uniform distribution of an active pharmaceutical ingredient (API) affects the quality of the final dosage form. This study investigated the relationship between powder mixing performance and tablet quality attributes using sodium naproxen as a model API with limited flowability. Powder mixtures were prepared in a V-type blender, and the mixing index evolution was evaluated at different rotational speeds. Tablets were subsequently produced either by direct compression or by pan granulation followed by compression, and their critical quality attributes, including tablet mass, thickness, crushing strength, abrasiveness, and API content variability, were evaluated. The mixing index rapidly increased during blending and reached high values for all investigated conditions; however, similar mixing efficiency did not result in equivalent tablet properties. Directly compressed tablets exhibited higher crushing strength, lower abrasiveness, and lower API content variability compared with tablets obtained after pan granulation. The results demonstrated that the powder processing route had a stronger influence on final tablet performance than differences in mixing speed within the investigated range. The combination of mixing index evaluation with tablet quality assessment provides a comprehensive approach for understanding the influence of powder processing conditions on pharmaceutical tablet performance.

Abstract: Diallyl ether possesses unique chemical activities due to its dual functional allyl group and ether bond and is thus a high-value-added fine chemical with diverse applications. In this work, thin-plate ZSM-5 is synthesized and then subjected to alkaline post-treatment to improve its catalytic performance for allyl alcohol etherification to diallyl ether. The study shows that the post-treatment impacts on both the microstructure and acidic properties of ZSM-5. Although the selectivity of diallyl ether obtained over different ZSM-5 catalysts are similarly high, the treatment with tetrapropylammonium hydroxide and/or dilute NaOH solutions enhances the conversion of allyl alcohol. The highest turnover number of the reaction achieves when there is a moderate amount of strong acid sites in ZSM-5. This study contributes to the knowledge base for potential application of ZSM-5 in diallyl ether production from allyl alcohol.

Abstract: In this work, the adsorption of a dye from aqueous solutions onto a waste chicken eggshell biosorbent is under consideration. The aim of this work is to assess the possibility of removing the textile dye, i.e., direct blue BR 200, from water by adsorption on eggshells and to generate the process data such as effective internal and external diffusion coefficients. The results of our experimental studies on adsorption equilibrium and kinetics are presented in this paper. The experiments are conducted for both eggshells and activated carbon in order to compare their adsorption efficiency. As a result of the equilibrium studies, the experimental adsorption isotherms are obtained. Moreover, the parameters of the Henry, Freundlich, Langmuir, Langmuir-Freundlich (Sips) and modified BET isotherms are determined based on the experimental data. In the kinetic studies the aqueous solution of a dye flows through the fixed-bed laboratory column. The adsorbent grains constitute the packing of the column. Based on the results of the kinetic studies, the external and internal diffusion coefficients for different process conditions i.e., different flow rates of the liquid phase in the adsorber, are determined. The internal diffusion coefficient, which describes the transfer from the external surface of an adsorbent grain to its interior, is calculated on the basis of the solution to Fick’s unsteady-state diffusion equation. The results of the experiments and calculations presented in this work can be used to determine the efficiency of eggshells as a biosorbent in water purification systems. It was obtained that the eggshells have very good sorption properties with respect to the dye under investigation. Both equilibrium and kinetic studies revealed that the dye uptakes for eggshells are greater than the uptakes for the activated carbon which is a conventional reference adsorbent. Moreover, the Langmuir-Freundlich (Sips) isotherm provides the best fit for the experimental data for both the eggshells and activated carbon. The external diffusion coefficient of the dye in water is D_AB = 2.21·10−10 m²/s. The kinetic calculations revealed that the effective internal diffusion coefficient D_s for both adsorbents is lower than the external coefficient D_AB and it increases with the liquid flow rate. It was also found that D_s for the eggshells is greater than for activated carbon. The obtained values of the internal diffusion coefficient D_s for the eggshells were 2.55·10−11 m²/s, 4.59·10−11 m²/s, 1.92·10−10 m²/s, for the flow rates 1.72 cm³/s, 2.31 cm³/s and 2.90 cm³/s, respectively. The D_s values refer to the equivalent radius of the eggshells grains R_p = 0.00146 m. The isotherms parameters and diffusion coefficients presented in this work can be used as data for process calculations.

Abstract: The rapid transition toward sustainable energy systems has created an urgent demand for advanced functional materials capable of improving energy conversion, storage, and utilization technologies. Artificial intelligence has emerged as a key enabling technology for accelerating materials discovery through data-driven prediction, inverse design, autonomous experimentation, and intelligent decision-making. This mini-review critically examines recent advances in AI-assisted discovery and optimization of advanced energy materials, covering machine learning, deep learning, graph neural networks, transformer models, generative AI, large language models, and self-driving laboratories. Unlike previous reviews that primarily focus on individual AI methodologies or specific classes of energy materials, this work provides an integrated assessment of recent developments across the entire AI-driven materials discovery workflow, encompassing data infrastructures, predictive modeling, generative design, autonomous experimentation, and intelligent closed-loop optimization. Representative studies demonstrate that AI-assisted optimization has reduced battery fast-charging optimization time from approximately 500 days to 16 days and achieved prediction accuracies of up to R2 = 0.88 in virtual materials screening. Representative studies further demonstrate that recent generative AI models have produced more than twice as many stable novel materials while generating structures over ten times closer to DFT ground-state configurations, whereas AI-assisted image analysis has achieved automated materials characterization with segmentation accuracies exceeding 91%. These advances demonstrate the growing practical value of artificial intelligence across batteries, photovoltaics, electrocatalysis, hydrogen technologies, and other sustainable energy applications. This mini-review further discusses recent progress in open materials databases, autonomous experimentation, foundation models, and AI-enabled research platforms that are reshaping modern materials development. Critical evaluation of the available literature indicates that data quality, model generalization, interpretability, computational cost, and experimental validation remain the principal barriers to broader implementation of AI in materials research. Based on the literature synthesized in this mini-review, future advances are expected to depend on the effective integration of generative AI, foundation models, physics-informed learning, and autonomous experimentation within intelligent closed-loop materials discovery ecosystems.

Abstract: The efficient conversion of solar energy into chemical fuels through artificial photosynthesis represents one of the most promising approaches for mitigating global energy shortages and anthropogenic CO₂ emissions. Nevertheless, simultaneously achieving highly selective CO₂ photoreduction and efficient hydrogen evolution remains challenging because of sluggish reaction kinetics, limited visible-light absorption, rapid charge recombination, and insufficient active sites. Herein, we propose a novel hierarchical photocatalyst comprising atomically dispersed Fe–Co dual single atoms anchored on a covalent organic framework (COF)/g-C₃N₄ heterostructure (Fe–Co-SA/COF/g-C₃N₄). The strong electronic interaction between neighbouring Fe and Co single atoms establishes abundant asymmetric Fe–N₄–Co catalytic motifs, while the crystalline COF provides highly ordered π-conjugated pathways that significantly accelerate charge transport. Simultaneously, intimate interfacial contact between the COF and g-C₃N₄ generates an efficient S-scheme heterojunction, promoting directional migration of photogenerated electrons and holes while preserving their strong redox potentials. Density Functional Theory (DFT) calculations reveal that the Fe–Co dual sites reduce the energy barrier for CO₂ activation by approximately 45% compared with isolated Fe sites, whereas Gibbs free-energy analysis demonstrates favorable adsorption of *COOH and *H intermediates. Artificial intelligence-assisted catalyst optimization further identifies the optimal Fe/Co atomic ratio and coordination environment, enabling ultrabroadband solar harvesting extending from ultraviolet to near-infrared wavelengths (300–1800 nm). Under simulated AM 1.5G solar irradiation, the optimized Fe–Co-SA/COF/g-C₃N₄ photocatalyst achieves remarkable CO evolution rates exceeding 1450 μmol g⁻¹ h⁻¹, CH₄ production of 165 μmol g⁻¹ h⁻¹, and H₂ evolution of 12.4 mmol g⁻¹ h⁻¹, together with an apparent quantum efficiency approaching 18.6% at 420 nm and a solar-to-fuel efficiency of 2.8%. Excellent photocatalytic stability is maintained over ten consecutive reaction cycles with negligible structural degradation. This work demonstrates how dual single-atom engineering integrated with crystalline COF/g-C₃N₄ heterostructures provides a powerful strategy for constructing next-generation artificial photosynthetic systems capable of simultaneously producing solar fuels and green hydrogen with exceptional efficiency.

Abstract: Dry reforming of methane represents a promising approach for the valorization of CO₂ captured from industrial emissions via a high-temperature catalytic process. To this aim, a LaMn1-xNixO3 catalyst with a perovskite structure (x=0.25) for dry reforming was obtained as ultrafine powder by solution combustion synthesis and then softly deposited over -alumina supports as structured catalyst. X-ray diffraction proved that the fresh catalyst exhibits the characteristic framework of corner-sharing BO6 oc-tahedra and Mn substitution in B site. Temperature programmed reduction in H2 showed two main peaks between 200 and 400 °C and between 700 and 900 °C, proving the strong reduction of Mn oxides in different oxidation states and Ni oxide even to the elemental state. Raman spectroscopy on fresh and spent catalyst showed that carbon deposition during reforming was negligible and lattice distortion occurred associated to oxygen vacancies or partial reduction. A 25-hour reforming test with LaMn1-xNixO3 proved conversion of CH4 equal to 75% at 700°C. Dry reforming tests with the struc-tured catalyst confirmed the results obtained with the catalyst powder on a larger scale and different conditions, such as temperature, residence time and CH4/CO2 feed ratio, achieving CH4 conversion of up to 94% at 800 °C.

Abstract: The conversion of carbon dioxide (CO₂) driven by microwave plasma has garnered extensive attention due to its capability to recycle carbon resources and mitigate the greenhouse effect. However, the existing microwave plasma technologies suffer from cumbersome system setups and relatively low energy efficiency. This work investigates the CO₂ conversion using a portable atmospheric microwave plasma source, which requires low plasma-generating power. When the working gas is a mixture of CO₂ and Ar, the minimum plasma-generating power required for the proposed portable microwave plasma source is only 50 W. A Fourier transform infrared spectrometer is used to quantify both the CO₂ and CO concentrations, and the C₂ Swan bands of the plasma are measured to determine the gas temperature. The maximum CO₂ conversion rate is approximately 12.7%. Furthermore, the maximum energy efficiency reaches 87.9%, which exceeds that of most of the state-of-the-art atmospheric microwave plasma configurations. Owing to its simplicity of operation, portability, and high energy efficiency, this method is well-suited for distributed CO₂ conversion systems.

Abstract: The scope o this study is to evidence by numerical simulation the influence of various parameters on the efficiency of an enzymatic packed bed reactor. The main characteristic of this reactor is that it contains a packed bed of immobilized enzymes crossed by a liquid substrate stream in order to get the desired product. This is carried out in order to evidence the influence of operating parameters on the substrate conversion rate at the reactor exit. The studied parameters are: bed thickness, feed flow rate, bed density and internal efficiency factor. The obtained results showed how would be these parameters in order to increase the substrate conversion rate at the reactor exit.

Abstract: Biomass thermochemical conversion-derived hydrochar has been increasingly recognized as a functional resource for environmental remediation, but knowledge of the effect of the carbonization conditions on the surface chemistry and binding behaviour of hydrochar is still limited. In this study, hydrochar from two different processing pathways: pressure reactor carbonization (P-RC) and microwave-assisted carbonization (M-RC), is compared to understand the mechanisms of contaminant interaction and the changes in structure that occur during the carbonization processing. P-RC was synthesized at the hydrothermal temperatures (180, 220, and 250 °C) for 2 and 5 h, while M-RC was synthesized at microwave irradiation for 30 minutes and 1 hour. TGA, SEM–EDS, FTIR, and XRD were used for comprehensive characterization, which revealed systematic differences in functional group distribution, mineral phases, and microstructural development between the two carbonization methods and at different carbonization temperatures. The increase in P-RC temperature led to greater aromatic condensation, thermal stability, and mineral reorganization, while M-RC maintained a higher percentage of oxygenated functionality and a more heterogeneous surface morphology. Batch adsorption experiments indicated that the M-RC hydrochar had a faster adsorption rate, attributed to its greater number of reactive oxygenated functionalities, whereas the P-RC hydrochar produced at higher temperatures exhibited a more even distribution of adsorption sites and stronger mineral-assisted interactions. The kinetics and isotherm modeling also showed different interaction pathways: for M-RC, surface complexation on heterogeneous sites was favored, whereas for P-RC, a more monolayer-like adsorption was observed. These results collectively show how the method and temperature of carbonization affect reactivity and support the establishment of mechanistic relationships crucial to maximizing the utility of hydrochar as a functional material for environmental remediation.

Abstract: Forced periodic operation (FPO) has emerged as a promising process intensification strategy for nonlinear catalytic reactors. In this study, the nonlinear frequency response (NFR) methodology was applied to investigate square-wave FPO of an isothermal CSTR for methanol synthesis. The analysis focused on periodic modulation of the inlet CO and flow rate, considering both single-input and simultaneous-input forcing. The reactor response was evaluated using higher-order frequency response functions (FRFs) to quantify the non-periodic component responsible for time-averaged process enhancement. The results showed that individual modulation of either inlet CO or flow rate doesn't provide significant improvement in reactor performance and may even reduce methanol productivity. In contrast, simultaneous modulation of both inputs generates a strong positive nonlinear interaction that substantially enhances reactor performance. Under optimal forcing conditions, methanol productivity increased from 336.9 mmol min⁻¹kgcat-1 at steady-state to 553.6 mmol min⁻¹kgcat-1, corresponding to a 64.3% improvement. Compared with previously reported cosine forcing, square-wave modulation nearly doubled the attainable productivity enhancement while also improving hydrogen utilisation efficiency. The results demonstrate that square-wave FPO represents a highly effective strategy for methanol synthesis intensification and confirm the capability of the NFR methodology for a priori evaluation and optimisation of periodically operated catalytic reactor systems.

Abstract: This study focuses on the synthesis of microporous carbon adsorbents derived from Shoptykol coal (Maikuben basin) via potassium hydroxide (KOH) chemical activation at two ratios (1:0.5 and 1:1), and on the evaluation of their hydrogen adsorption–desorption performance. The samples were prepared under an inert nitrogen atmosphere and characterized using particle size analysis, thermogravimetric analysis, BET surface area measurements, SEM/TEM microscopy, and gas sorption techniques. Hydrogen storage behavior was investigated using a high-pressure volumetric adsorption system over a wide range of pressures and temperatures, including cryogenic conditions (77 K and 80 bar). The experimental data were analyzed using Langmuir isotherm modeling, kinetic models (pseudo-first and pseudo-second order, Weber–Morris diffusion), and thermodynamic approaches based on van’t Hoff and Arrhenius equations. The Shoptykol:KOH (1:1) sample demonstrated higher adsorption capacity, achieving up to 6.6 wt% hydrogen storage at 77 K and 80 bar, as well as faster adsorption–desorption kinetics and lower activation energy compared to the 1:0.5 sample. Overall, optimized alkaline activation of coal-derived carbon materials is an effective strategy for producing high-performance adsorbents, and the 1:1 sample shows superior hydrogen storage properties for energy storage applications.

Abstract: Perovskite solar cells (PSCs) have emerged as highly promising candidates for next-generation photovoltaic technologies due to their remarkable power conversion efficiencies, low-cost fabrication routes, and tunable optoelectronic properties. However, their practical commercialization remains constrained by several critical challenges, including charge-carrier recombination, interface-related energy losses, environmental instability, and lead-associated concerns. This review presents a focused and updated analysis of advanced charge-carrier management strategies designed to address these limitations. Unlike broader PSC reviews, particular emphasis is placed on the coupled roles of carrier lifetime, mobility, and interface quality as fundamental determinants of device efficiency and long-term operational stability. Special attention is devoted to inverted p-i-n architectures, where buried hole-selective contacts, self-assembled monolayers, NiOx-based interlayers, and fullerene-derived electron-selective contacts increasingly govern voltage losses, extraction balance, operational durability, and scalability. Recent developments are discussed through the interconnected effects of buried-interface passivation, transport-layer energetics, crystallization control, and transient/steady-state characterization methods used to quantify non-radiative recombination and transport limitations. The scalability and reproducibility of these approaches are further evaluated under realistic operating conditions. Analysis of recent representative studies indicates that further improvements in PSC performance are increasingly limited not by intrinsic absorber properties alone, but by interfacial recombination, contact non-uniformity, and the long-term stability of carrier-selective interfaces under thermal, electrical, and operational stress. Recent evidence suggests that further progress in PSC technology will increasingly depend on integrated control of charge-carrier dynamics across buried interfaces, transport layers, and scalable device architectures, particularly in formamidinium-rich and inverted p-i-n systems that currently represent the most promising platforms for durable high-efficiency photovoltaics.

Abstract: Direct compression is a widely used manufacturing method for solid oral dosage forms; however, its performance strongly depends on powder flowability, cohesiveness, and compactability, particularly in systems containing fine cohesive particles. This study investigated the influence of mixing time, fill level, and rotational speed on the properties of sodium naproxen–calcium carbonate blends and the resulting tablets prepared by direct compression. Powder blends were produced in a V-type mixer according to a central composite design, and the effects of process variables were evaluated using response surface methodology and analysis of variance. Blend properties were characterized by the angle of repose, angle of fall, and angle of difference, whereas tablet quality was assessed in terms of thickness, mass, active pharmaceutical ingredient content, and abrasiveness. Mixing time significantly affected the angle of difference, indicating changes in blend cohesiveness and flow uniformity, while fill level was identified as the main factor influencing active pharmaceutical ingredient content uniformity. Response surface analysis enabled identification of operating regions satisfying predefined criteria for blend homogeneity, active pharmaceutical ingredient content, and abrasiveness. The results provide guidance for optimization of direct compression processes involving cohesive pharmaceutical powders and support the application of Quality by Design principles in tablet manufacturing.

Abstract: Aluminium powder, an energetic material, is prone to thermal runaway upon water exposure under local heat sources, yet the nonadiabatic mechanisms of micron sized accumulated aluminium powder under localized heating remain unclear. This study employs a proprietary characterization platform to investigate the effects of particle size, water content, and local heat source power on heat transfer in the dry state and on parameters including induction time, onset temperature, peak heat release rate, and reaction heat during the induction and main reaction phases. In the dry state, decreasing particle size enhances effective thermal conductivity and accelerates temperature rise, whereas elevated local heat source power exacerbates thermal inertia. Under local heating upon water exposure, reduced particle size significantly enhances reactivity; the reaction heat of 2 μm powder reaches 983 J/g, approximately fourfoldAs shown in Figure9 that of 106 μm powder. Water content exhibits nonmonotonic regulation, with onset temperature minimizing at 25% water content and 66.4 °C and reaction heat peaking at 33%. Paradoxically, elevated local heat source power suppresses reaction intensity, and reaction heat at 10 W is one sixth of that at 2.5 W, attributed to rapid product layer densification and the steam film barrier effect shifting the controlling mechanism from chemical to diffusion control. A coupled multifactorial predictive model incorporating the three factors was established with R2 of 0.92, providing data and guidance for aluminium powder storage hazard prevention.

Abstract: Habanero pepper (Capsicum chinense Jacq. var. Jaguar) leaves are an underutilized by-product and a source of phenolic compounds. This study evaluates how natural deep eutectic solvents (NADES) formulation and processing conditions with ultrasound-assisted extraction (UAE) modulate selective phenolic recovery. A 2×3×2 factorial design evaluated the hydrogen bond acceptor (HBA) in NADES (choline chloride, ChCl; malic acid, MAc), UAE time (10 min, 20 min, 30 min), and leaf drying (freeze-drying, FzD; oven-drying, OvD). Total phenolic content (TPC, Folin–Ciocalteu), antioxidant capacity (Ax, DPPH methodology), and individual polyphenols (liquid chromatography) were determined. The highest TPC was obtained with ChCl from FzD leaves at 10 min UAE (36.18 ± 0.70 mg GAE/g dry leaf). Maximum Ax occurred for OvD leaves at 30 min and did not differ between HBAs (ChCl 86.43 ± 0.65%; MAc 86.95 ± 0.18%). UPLC-DAD confirmed selectivity, highlighting catechin (51.14 ± 1.07 mg/g; MA, FzD, 20 min), chlorogenic acid (16.05 ± 0.09 mg/g; MA, OvD, 10 min), and quercetin + luteolin (5.37 ± 0.05 mg/g; MA, FzD, 10 min). Modulation could be explained by HBA-dependent polarity and hydrogen-bonding that alters solvation of phenolic compounds, while UAE enhances mass transfer and cell disruption, and drying-dependent matrix structure affect phenolic stability and release. These results show the behavior between total and individual phenolic compounds and the Ax, which guides the evaluation of UAE/NADES conditions for the targeted extraction of phenolic compounds of interest in the pharmaceutical, food and cosmetic industries from the leaf of Capsicum chinense.

Abstract: Sulforaphane (SFN), a bioactive compound sourced from cruciferous vegetables, offers significant antioxidant and anti-inflammatory benefits yet, its stability in animal feed is a challenge. Nanotechnology-based encapsulation, specifically ionic gelation, has demonstrated efficacy in improving the stability and bioavailability of SFN. This review examines the application of natural polymers such as chitosan and alginate in ionic gelation for the encapsulation of SFN. It also discusses how these polymers can prevent SFN from degrading while traversing the digestive tract. Encapsulated SFN has shown enhanced nutritional absorption, elevated immune responses, and reduced oxidative stress in animals. However, challenges persist in identifying optimal methods for encapsulating various species, including enhancing encapsulation effectiveness, particle size, and controlled release mechanisms. Additionally, regulatory concerns regarding the safety and environmental impacts of nanoparticles in feed must be addressed. Future research should focus on improving encapsulation techniques and ensuring the safe application of SFN-loaded nanocarriers in livestock feed.

Abstract: Li-ion batteries (LIBs) are seeing increasingly widespread adoption across consumer electronics, electric vehicles, and grid-scale energy storage systems, yet their susceptibility to thermal runaway remains a concern. This study evaluates ethoxy(pentafluoro)cyclotriphosphazene (PFPN) as an electrolyte additive to improve electrolyte flammability and thermal stability without compromising electrochemical performance. Electrolyte flammability was quantified using Self-Extinguishing Time (SET) measurements, which revealed that PFPN significantly suppresses combustion. At 4 wt% PFPN, 67% of electrolyte samples failed to ignite despite extended ignition exposure, and the average SET decreased by 43% (from 51 s g⁻¹ to 29 s g⁻¹). Differential Scanning Calorimetry (DSC) further demonstrated improved thermal stability, with the onset of solvent decomposition delayed by ~30 °C at 4 wt% PFPN. Ionic conductivity modestly decreases (11%, from 10.26 to 9.12 mS cm⁻¹ at 4 wt% PFPN). Electrochemical testing showed negligible impact on battery performance. Graphite||Li and NMC811||Li half-cells containing PFPN exhibited comparable capacity retention to baseline cells. NMC811||Graphite pouch cells were used to further evaluate extended cycling and rate capability, PFPN containing cells demonstrated similar capacities even after prolonged cycling and high-rate operation. Overall, PFPN provides effective flame retardance at concentrations as low as 4 wt% while maintaining electrochemical compatibility, making it a promising additive for enhancing thermal stability of LIB electrolytes.

Abstract: The persistence of pharmaceutical contaminants such as carbamazepine (CBZ) in aquatic environments presents a growing challenge for conventional wastewater treatment processes. In this study, potato peel waste was valorised into carbonaceous adsorbents via hydrothermal carbonization (HTC) and conventional pyrolysis, and their performance for CBZ removal from water was systematically compared. Hydrochars were prepared at 200 °C under varying residence times and biomass-to-water ratios, while biochars were produced at 400 °C using KOH activation under different reaction times and impregnation ratios. The materials were characterised using BET surface area analysis, CHNS elemental analysis, and FTIR spectroscopy. Adsorption experiments revealed that HTC-derived hydrochars achieved outstanding CBZ removal efficiencies (up to ~100%) and high uptake capacities (~50 mg g⁻¹) within one minute of contact, despite relatively low surface areas (< 2 m² g⁻¹). In contrast, pyrolysis biochars exhibited significantly lower removal efficiencies (7–55%) and slower, less stable adsorption behaviour. Correlation analysis demonstrated that CBZ removal was strongly associated with surface chemistry—particularly carbon, hydrogen, and nitrogen content and N/C ratio—rather than BET surface area or pore diameter. FTIR analysis indicated that π–π interactions, hydrogen bonding, and pore filling collectively govern CBZ adsorption, with oxygen- and nitrogen-containing functional groups playing a dominant role in rapid uptake. These findings highlight hydrothermal carbonization as an effective, low-severity route for producing high-performance adsorbents from food waste and demonstrate the potential of potato peel–derived hydrochars for rapid pharmaceutical remediation in water treatment applications.

Abstract: Dry reforming of methane (DRM) is an attractive route for H2 production and simultaneous CO₂ utilization, but its practical implementation is limited by catalyst deactivation. This study experimentally investigates the catalytic performance of Ni/Al₂O₃ and Gd-doped ceria–promoted Ni/GDC–Al₂O₃ catalysts for DRM in a fixed-bed quartz reactor over 400–800 °C at gas residence times of 0.1 s and 0.4 s. Increasing temperature and residence time enhanced CH₄ and CO₂ conversion as well as H₂ and CO yields for both catalysts. The GDC-promoted catalyst exhibited markedly improved activity, achieving conversions and product yields at 0.1 s comparable to those of Ni/Al₂O₃ at 0.4 s and reaching complete CH₄ conversion at about 650 °C, approximately 100 °C lower than the Ni/Al₂O₃. Long-term testing demonstrated high durability of Ni/GDC–Al₂O₃ at 650 °C with no detectable carbon deposition, consistent with thermodynamic equilibrium analysis.