Search Results (1,448)

Low-cost, efficient, and durable electrocatalysts for two-electron oxygen reduction (2e⁻ ORR) to synthesize hydrogen peroxide (H₂O₂) are essential for sustainable chemical manufacturing. Herein, we report a sustainable route to prepare activated carbon electrodes (ASC) from municipal sludge via chemical activation and pyrolysis. The electrode activated with 30 wt.% H₃PO₄ and calcined at 600 °C for 2 h exhibited high catalytic activity. This electrode featured a hierarchical micro-/meso-/macroporous structure with a high BET surface area of 806.20 m²·g⁻¹, abundant carboxyl groups (surface O content of 4.0 at.%), and high hydrophobicity (contact angle of 121.6°). The unique hierarchical porosity, high surface area, hydrophobic surface, and carboxyl functionalities synergistically enhanced O₂ mass transfer, exposed abundant accessible active sites, and stabilized the triple-phase interface. Electrochemical evaluation revealed that 30 wt.% H₃PO₄-ASC achieved a high H₂O₂ selectivity of 86–92% with an electron transfer number of 2.2, approaching the ideal 2e⁻ ORR pathway. Under optimized conditions (pH = 3, j = 5.0 mA·cm⁻²), it produced 997.3 mg·L⁻¹ of H₂O₂ in 90 min, with a current efficiency of 68.8% and an energy consumption of 27.6 kWh·kg⁻¹ H₂O₂. Moreover, the electrode retained 81.1% of its initial H₂O₂ production after 15 cycles, demonstrating good reusability and long-term stability. This work offers a sustainable strategy for high-value utilization of municipal sludge and advances the development of efficient electrocatalysts for green H₂O₂ production. Full article

Metal–organic framework (MOF)-derived materials have recently emerged as promising sensing materials because of their tunable composition, porous architecture, high surface area, and defect-rich structures. Therefore, MOF-derived materials have significantly attracted the scientific community to design and fabricate triethylamine (TEA) gas sensors. TEA is a toxic, volatile, and malodorous amine that is widely released from industrial processes, food spoilage, and environmental sources. The selective and sensitive detection of TEA is of great importance for health, safety, and environmental monitoring. Previous years have witnessed rapid growth in the development of MOF-derived materials based on TEA gas sensors. This review critically evaluates recent progress in the fabrication of MOF-derived metal oxides, mixed-metal oxides, doped systems, noble-metal-functionalized materials, carbon-containing composites, MXene-integrated architectures, and heterojunction-based TEA gas sensors. The response, selectivity, stability, and sensing mechanisms for TEA gas sensors are discussed. Furthermore, challenges and perspectives are discussed. We believe that this review may be beneficial for those actively working in the fabrication of MOF-based TEA gas sensors. Full article

Baijiu brewing generates large quantities of wastewater sludge, which presents major disposal challenges but contains abundant organic matter and nutrients, indicating great potential as a soil amendment. This study investigated the soil amendment effects of granulated and coated Baijiu brewing sludge through a 112-day soil column leaching experiment. Sludge particles were coated with sodium alginate (SA), polyvinyl alcohol (PVA), and ester gum (EG), and compared with untreated air-dried sludge (CK₁), uncoated granulated sludge (CK₂), compound fertilizer (F), and a blank control (B). The results showed that coated sludge treatments significantly increased soil leachate pH, total organic carbon, total nitrogen, total phosphorus, and total potassium, and exhibited obvious controlled-release effects on nitrogen, phosphorus, and potassium nutrients compared with uncoated sludge. Soil enzyme analysis indicated that SA treatment increased catalase activity, acid phosphatase activity was generally enhanced by sludge addition, and urease activity was reduced in coated sludge treatments. FTIR and BET analysis showed that both coated and uncoated sludge increased soil-specific surface area and changed soil pore structure. These findings confirm that granulated and coated Baijiu brewing sludge can be used as an effective slow-release soil amendment, and sodium alginate coating shows the most comprehensive improvement in multiple soil health indicators, with high application value for resource utilization of Baijiu sludge and soil quality improvement. Full article

Per- and polyfluoroalkyl substances (PFAS) such as perfluorooctanoic acid (PFOA) persist in aquatic environments due to their extremely strong C–F bonds and high environmental stability/poor biodegradability, creating an urgent demand for high-performance and scalable adsorption treatment technologies. This study reports the synthesis, characterization, and fixed-bed column adsorption performance of a dual-polymer-modified activated carbon adsorbent engineered for enhanced PFAS capture. Activated carbon (AC) was sequentially functionalized with polyethyleneimine (PEI) and poly(chlorotrifluoroethylene–co-vinylidene fluoride) (Kel–F) to form the fluorine-rich, amine-grafted composites AC–PEI–KelF and AC–PEI–KelF–PEI. Surface-area studies of the modified AC adsorbents showed a reduction in surface area of about a factor of two, possibly due to pore blockage by the polymers. Continuous-flow column breakthrough studies demonstrated dramatic improvements in perfluorooctanoic acid (PFOA) removal efficiency, with 50% maximum breakthrough time increasing from 80 min for AC to 540 min for AC–PEI–KelF and 1500 min for the AC–PEI–KelF–PEI formulation. Thomas model adsorption capacities for AC, AC–PEI–KelF and AC–PEI–KelF–PEI were, respectively, 65, 490, and 1130 mg/g. The adsorption mechanism, using selective mobile phases, was shown to be due to a combination of electrostatic and hydrophobic/fluorophilic interactions. Kinetic analysis showed that adsorption exhibited pseudo-second-order behavior, with multi-stage intraparticle diffusion. The optimized composite also exhibited strong regeneration stability, retaining 79% performance after six adsorption–desorption cycles, and displayed high selectivity for PFOA, even in the presence of structurally related competitors such as octanoic acid. The adsorption of perfluoropentanoic acid and undecafluoro-2-methyl-3-oxahexanoic acid (GenX) was also significant, and some interaction with trifluoroacetic acid was noted. Full article

Iron (Fe) contamination of water sources has become an increasing environmental concern, creating the need for effective, environmentally friendly, and cost-effective technologies for Fe(III) removal from aqueous systems. In the present work, the possibility of using the sulfuric acid-activated carbon made of Vigna trilobata rind waste for treating water contaminated with Fe ions was explored. The characteristics of the synthesized material were identified by physical, chemical, and spectroscopic methods, and its Fe ion sorption efficiency was studied experimentally in batch mode under various conditions. Equilibrium, kinetics, and thermodynamics of Fe ion removal by the prepared adsorbent were determined. The obtained adsorbent had a BET surface area of 20.55 m² g⁻¹ and showed high experimental adsorption capacity with the highest observed uptake of 19.81 mg g⁻¹. Based on the experimental results, the equilibrium data could be best described by the Langmuir equation (R² = 0.978). Kinetic analysis showed that the rate-limiting step in Fe ion sorption was intraparticle diffusion (R² = 0.921). Thermodynamic calculations indicated that the adsorption process occurred spontaneously (ΔG° = −4.31 to −6.53 kJ mol⁻¹) and endothermically (ΔH° = +7.11 kJ mol⁻¹). A comparative analysis showed that the sorption capacity of the studied adsorbent corresponded to that reported for the analogous materials produced from other biomasses. Full article

The presence of aflatoxin B1 (AFB1) is ubiquitous in the environment, and it is considered one of the most powerful natural carcinogenic substances. In this study, a highly sensitive electrochemical aptasensor was designed to detect aflatoxin B1 (AFB1) in peanuts. Iron–cobalt-doped magnetic carbon (Fe-Co/NPC) was used to enhance the conductivity of the electrode and catalytic performance, providing an increased specific surface area. Gold nanoparticles (AuNPs) were used to immobilize an aptamer. And cDNA-polyacrylic acid (cDNA-PAA) nanogels served as a high-density carrier for cDNA and an active signal amplification unit, significantly increasing the charge transfer resistance (Rct) through steric hindrance and electrostatic repulsion. Unlike traditional aptasensors that relied on passive blocking agents, we designed a competitive displacement mechanism. AFB1 competed with cDNA-PAA during detection in order to bind to the aptamer, which resulted in the removal of the non-conductive complex and a substantial increase in the electrochemical signal. Under the optimal conditions, the aptasensor had a linear response range of 1–1000 ng/L and a limit of detection (LOD) of 0.3 ng/L. It displayed high specificity, reproducibility, and stability. In spiked peanut samples, the recoveries ranged from 98.04% to 100.86%. Due to its sensitivity and reliability, this aptasensor has a great determination of AFB1 in food safety applications. Full article

Lignite-derived activated carbon (L-AC) was fabricated via a microwave-assisted KOH activation process using a low-rank Mae Moh lignite and explored its potential as an adsorbent solid for post-combustion CO₂ capture. Optimization of the KOH ratio, microwave irradiation power, and activation time gave rise to a product with a BET surface area of 1349 m² g⁻¹ and total pore volume of 0.78 cm³ g⁻¹, which represented 165 times and 78 times enhancement compared with that of the initial lignite, respectively. Scanning electron microscope (SEM) images proved the formation of a hierarchical macropore–mesopore–micropore structure, whereas Raman (I_D/I_G = 1.83) and Fourier-transform infrared spectroscopy analyses revealed a graphitic-like structure rich in defects with the existence of C=O and C–O–C functional groups involved in the Lewis acid–base interaction between L-AC and CO₂ molecules. Dynamic fixed-bed breakthrough tests performed at temperatures of 298, 328, and 353 K under post-combustion relevant conditions (CO₂ concentration: 15%, pressure: 1 atm) yielded CO₂ equilibrium uptake capacities of 47.34, 34.37, and 21.34 mg g⁻¹, respectively, with outstanding cyclic stability achieved after six consecutive adsorption–desorption cycles of temperature swing adsorption–desorption at 393 K. Among the seven nonlinear kinetic models, the Avrami, FL-PFO, and general-order models exhibited the highest fitting accuracy (R² = 0.9994–0.9998), suggesting that CO₂ adsorption onto L-AC proceeds through heterogeneous, multi-stage adsorption kinetics. A Weber–Morris intra-particle diffusion analysis identified a three-stage sequential transport mechanism in which mesopore diffusion constitutes the primary rate-limiting step. Thermodynamic parameters confirmed spontaneous (ΔG° = −24.20 to −26.87 kJ mol⁻¹), exothermic (ΔH° = −9.42 kJ mol⁻¹), and entropy-assisted adsorption (ΔS° = +49.93 J mol⁻¹ K⁻¹) consistent with a physisorption mechanism, corroborated by a low activation energy of 9.11 kJ mol⁻¹. These findings demonstrate the viability of low-rank lignite as a low-cost precursor for the scalable synthesis of high-performance carbonaceous CO₂ adsorbents for post-combustion capture applications. Full article

This review covers literature published up to June 2026. Detecting various water pollutants quickly and reliably remains a challenge. Boron-doped diamond (BDD) electrodes, particularly when fabricated as nanostructured thin films such as nanocones or nanowalls, offer a wide electrochemical window, low background current, and excellent chemical stability, making them promising tools for electrochemical sensing. However, unmodified BDD electrodes face an inherent trade-off among conductivity, active site density, and interfacial stability, a phenomenon termed herein the “sensitivity-selectivity-stability triangle bottleneck”, which severely limits practical performance. In this review, we demonstrate how multi-scale structural regulation can circumvent this bottleneck. Specifically, a triple strategy comprising boron doping, surface modification, and post-annealing treatment is proposed and evaluated. First, the effect of boron doping level on conductivity and active site density is discussed. Second, two common surface modification approaches are examined: carbon nanomaterials (which increase surface area and form conductive networks) and metal nanoparticles (which enhance catalytic activity and interfacial charge transfer). Third, post-annealing is highlighted as a key synergistic step that locks the modified layer and stabilizes the interface. Together, these three components form an integrated framework. To provide concrete guidance, the performance of each strategy is compared for representative water pollutants, including heavy metal ions, phenolic compounds, and emerging contaminants such as antibiotics and pesticides, with emphasis on sensitivity, selectivity, and stability. Representative detection limits achieved include 0.01 μg/L for Pb²⁺, 5 nM for acetaminophen, and 0.32 fM for PCB-77, demonstrating the effectiveness of the triple structural regulation strategy. Finally, in line with the theme of this Nanomaterials Special Issue on nanostructured thin films, current challenges in structural regulation are summarized, and future directions, including multi-parameter optimization, AI-assisted high-throughput screening, and real-world testing, are outlined. The goal is to offer practical structure-performance guidelines for designing BDD-based electrochemical sensors that are both high-performing and durable. Full article

To address the inherent drawbacks of peroxymonosulfate advanced oxidation processes (PMS-AOPs), including the low efficiency of reactive species production, short radical half-lives, and restricted pollutant degradation performance, sodium salt-assisted modification was adopted to fabricate ZIF-8-derived carbon. In this study, sodium salt-assisted modification was adopted to treat ZIF-8, and the chlorine-doped derived carbon materials HNC-T_x-Cl were prepared for peroxymonosulfate activation and tetracycline degradation in water. Compared with NC-800 fabricated by direct calcination of ZIF-8 at 800 °C, HNC-800-Cl synthesized via NaCl-assisted calcination exhibits more abundant pore structures and richer carbon defects, with a specific surface area of 1115 m²/g and a high graphitic defect ratio I_D/I_G of 1.20. Catalytic tests reveal that HNC-800-Cl achieves 93.39% tetracycline removal within 90 min at a catalyst dosage of 0.05 g L⁻¹ and PMS concentration of 0.1 mM. The system possesses a strong anti-interference ability toward complex water environments, maintaining a favorable degradation performance in the presence of coexisting anions, natural organic matter and actual water matrices. It also exhibits outstanding cycling stability, retaining a removal rate of 80.34% after five recycling runs. Radical quenching experiments and EPR characterization verify that superoxide radical (·O₂⁻) is the dominant reactive species during tetracycline degradation. Both the radical and non-radical pathways are clarified to illustrate the mechanisms of PMS activation and pollutant degradation. This work provides a novel catalytic material strategy to overcome the deficiencies of conventional PMS-AOPs, and offers a new perspective for structural regulation and non-metallic doping modification of ZIF-8-derived carbon materials. Full article

The selective gas-phase oxidation of γ-picoline (γ-P) to isonicotinic acid (INA)—a key precursor for the anti-tuberculosis drug isoniazid—was investigated over a V–Mn oxide catalyst as a solvent-free, waste-minimizing alternative to conventional liquid-phase synthesis routes. XRD and Raman spectroscopy confirmed the formation of a stable manganese vanadate crystalline phase with a high concentration of terminal vanadyl groups (V=O), providing well-defined redox-active sites. Water vapour proved essential for sustainable process performance: at an optimal H₂O/substrate molar ratio of 98, γ-picoline conversion reached 94.8% with INA selectivity of 86.5%, eliminating the need for hazardous solvents or additives. NH₃-TPD and kinetic analysis revealed that water vapour acts as a competitive adsorbent at vanadium Lewis acid sites, accelerating target product desorption and suppressing deep oxidation to COx—directly reducing carbon waste. Long-term stability was assessed over 96 h of continuous operation: the 23.4% decline in specific surface area correlated with an equivalent reduction in total acidity, while pore diameter expansion from 2.07 to 3.25 nm mitigated diffusion limitations, partially compensating for deactivation. These findings establish the V–Mn oxide system as a promising green catalytic platform for upgrading petrochemical fractions into high-value pharmaceutical intermediates with reduced environmental impact. Full article

The formation of carbon nanostructures and silicon carbide (SiC) using a single-source precursor offers a simplified route for material synthesis; however, the factors governing the transition between CNT-like structure formation and SiC growth remain unclear. In this study, the growth behavior of carbon-related structures using vinylsilane was systematically investigated by hot-wall chemical vapor deposition (CVD) on various substrates, including Fe bulk substrates and Fe thin films on SiO₂/Si. CNT-like structures were preferentially formed on Fe bulk substrates, whereas Fe thin-film substrates exhibited CNT-like growth at the initial stage followed by increased Si–C-related phase formation with increasing growth temperature and growth time. In contrast, on Fe thin films with limited catalyst amounts, CNT-like growth occurred initially, followed by increased Si–C-related phase formation with increasing growth temperature and growth time. These observations are consistent with a growth transition associated with the balance between Si uptake into the metal and surface SiC formation processes. By controlling catalyst amount, growth temperature, and growth time, the relative formation of CNT-like structures, SiC-rich coatings, and intermediate morphologies could be tuned within a single process. Furthermore, a SiC/CNT-like composite structure was directly formed on a conductive Fe substrate in a one-step CVD process. Electrochemical measurements showed an enhanced current response compared with a bare Fe substrate, indicating preliminary electrochemical activity and suggesting potential applicability as a high-surface-area electrode platform. Full article

Marine biowaste (fish and crustacean processing residues) is produced in tens of millions of tons annually, yet remains dramatically underutilized as a feedstock. Hydrothermal carbonization offers a technically attractive valorization route for these high-moisture, non-lignocellulosic materials, converting them to carbon-enriched hydrochar without the energy-intensive pre-drying required by pyrolysis. This focused review treats marine animal waste as the primary studies and micro- and macroalgal hydrothermal carbonization as a comparative benchmark to understand how the current research is going, the impact of production parameters, potential application, and possible research gaps to explore. Crustacean waste yields substantially more hydrochar (37–69%) than fish waste (15–34%) under equivalent conditions, driven by calcium carbonate retention in the solid phase. Unactivated hydrochars have low BET surface areas (<30 m²/g) and modest adsorption capacities (~10 mg/g). Acid deashing followed by KOH activation at 700 °C unlocks nanoporous structures with BET surface areas up to 680 m²/g and oxytetracycline adsorption capacities of 61.3 mg/g. Critical research gaps include the absence of techno-economic analysis, limited life-cycle assessment, and non-standardized reporting conventions. These must be addressed before upscaling to industrial viability can be achieved. Full article

In this study, lamellar MFI (Mobile Five-membered ring Intergrowth) zeolites pillared with TiO₂ were synthesized using tetraethyl orthotitanate (TEOTi) as titanium precursor and evaluated as photocatalysts for Rhodamine B (RhB) degradation under UV irradiation. The materials were characterized by X-ray diffraction (XRD), UV–Vis spectroscopy, N₂ adsorption–desorption, photoluminescence spectroscopy (PL), and transmission electron microscopy (TEM). XRD confirmed the preservation of the lamellar MFI structure and the formation of anatase TiO₂ pillars within the interlayer space. The composites exhibited hierarchical micro/mesoporosity, high surface areas (>320 m² g⁻¹), and mesopore sizes of approximately 4.1–4.2 nm. Photocatalytic experiments revealed that the incorporation of TiO₂ into the lamellar MFI framework significantly enhanced the degradation kinetics of RhB compared with bare TiO₂. The apparent pseudo-first-order rate constants followed the order MFIPTi-6 > MFIPTi-3 > MFIPTi-12 > TiO₂ > MFIPTi-24, with MFIPTi-6 exhibiting the highest activity (k_app = 0.049 min⁻¹), approximately 1.6 times higher than that of pure TiO₂. Scavenger experiments identified hydroxyl radicals as the predominant reactive species involved in the degradation process. TOC (Total Organic Carbon) measurements showed approximately 80% organic carbon removal, while recyclability tests demonstrated stable photocatalytic performance over six consecutive cycles. These results highlight the potential of lamellar TiO₂/MFI composites as efficient and reusable photocatalysts for water treatment applications. Full article

Under the “dual carbon” goals, Taiyuan, a prefecture-level administrative unit and energy-intensive region in Shanxi Province, China, has experienced changes in soil carbon storage and soil carbon flux under rapid urbanization and industrialization. To clarify the spatial patterns of soil carbon storage and flux, 26 field sampling sites, including 78 soil samples, were analyzed using laboratory measurements and an optimized tunable diode laser absorption spectroscopy–geographic information system (TDLAS–GIS) integrated monitoring approach. This study investigated the spatial patterns of soil carbon storage and flux and discussed their potentially associated factors, providing an exploratory workflow for regional carbon monitoring. The results showed clear spatial heterogeneity, with an average soil organic carbon (SOC) content of 10.86 g/kg. High-SOC areas were mainly located in the southern and southwestern plains, while lower SOC levels occurred in urban expansion zones and highly disturbed surfaces. The western mountainous areas were important ecological barriers but were not the highest measured SOC zones. At the site level, arable land and forestland showed higher mean SOC values than grassland, with average SOC contents of 12.47, 12.07, and 8.27 g/kg, respectively, although these land-use-related differences were not statistically significant. Soil carbon flux was relatively higher in some mountainous regions and industrial–ecological transition areas but lower in several urban expansion areas. The results suggest that urbanization and industrial activity may be associated with changes in SOC and soil-atmosphere CO₂ exchange. This study describes the spatial variation characteristics of soil carbon storage and flux, establishes a reproducible TDLAS–GIS workflow for regional carbon monitoring, and provides exploratory support for ecological sustainability, sustainable land management, and the “dual carbon” strategy in northern resource-based cities. Full article

Lead (Pb²⁺) and cadmium (Cd²⁺) are among the most hazardous heavy metal pollutants in wastewater owing to their high toxicity, environmental persistence, and detrimental impacts on human health and aquatic ecosystems. In this study, a novel ternary magnetic composite, SnFe₂O₄/activated carbon/polypyrrole (SnFe₂O₄/AC/PPy), was effectively synthesized and tested as an effective adsorbent in the removal of Pb²⁺ and Cd²⁺ from aqueous water. The composite was prepared by depositing spinel SnFe₂O₄ nanoparticles on activated carbon, followed by in situ polymerization of polypyrrole to enhance surface functionality and adsorption affinity. The successful fabrication of the porous SnFe₂O₄/AC/PPy hybrid composite was confirmed through FTIR, XRD, SEM–EDS, BET, XPS, and VSM characterization. The composite demonstrated a relatively high surface area (352.3 m²/g) and adequate magnetic responsiveness (12.33 emu/g), ensuring facile magnetic separation following wastewater treatment. Batch adsorption experiments showed great removal efficiency of 95.02 and 92.48% for Pb²⁺ and Cd²⁺ ions, respectively, at optimum conditions. The adsorption equilibrium data followed the Langmuir isotherm model with maximum adsorption capacities of 187.07 mg/g for Pb²⁺ and 96.45 mg/g for Cd²⁺ ions, which were attributed to monolayer adsorption on homogenous active sites. The kinetic and isothermal model indicated that the adsorption process was controlled by the combination of physical and chemical interactions. Thermodynamic parameters showed negative Gibbs free energy and enthalpy changes (ΔH° = −49.74 kJ/mol for Pb²⁺ and −38.82 kJ/mol for Cd²⁺ ions), confirming the spontaneous and exothermic nature of adsorption. Furthermore, the increasingly negative ΔG° values at lower temperatures indicated that the adsorption was thermodynamically more favorable under cooler conditions. According to the regeneration studies, the composite maintained a high removal efficiency after five consecutive cycles. In general, SnFe₂O₄/AC/PPy composite has good potential as a stable, reusable, and high-performance adsorbent to treat heavy metal wastewater. Full article