Search Results (4,072)

Long-term conservation tillage can alter soil properties and crop performance in a depth-dependent manner. We evaluated a 2 × 2 factorial experiment combining tillage practice (conventional plowing vs. no-tillage) and organic manure application (without vs. with organic manure) in rainfed winter wheat on the Loess Plateau. Soil nutrients, aggregate stability, N₂-adsorption-derived surface and pore properties, and bulk density were measured at 0–10, 10–20, and 20–40 cm, and grain yield was analyzed from 2011 to 2025. Two-way ANOVA showed that no-tillage generally increased surface-soil nutrient contents and aggregate stability, with the strongest responses at 0–10 cm. Significant tillage × organic manure application interactions for several nutrient properties indicated manure-dependent responses to tillage. These effects generally weakened with soil depth, demonstrating pronounced vertical stratification. Management effects on N₂-adsorption-derived surface and pore properties were limited, whereas no-tillage increased bulk density mainly within the upper 20 cm. Based on the descriptive 15-year yield analysis, NT had the numerically highest mean and cumulative yields and the lowest interannual variability. Overall, no-tillage enhanced surface-soil fertility and aggregate stability, but nutrient stratification and increased soil consolidation should be considered when optimizing long-term management. Full article

Spent hops generated during the dry-hopping stage of beer production were investigated as a precursor for the production of biochar and ZnCl₂-activated carbon for phenol adsorption from aqueous solutions. The effects of production conditions on adsorption performance were evaluated through factorial experimental designs, and the resulting materials were characterized by SEM, FTIR, and N₂ adsorption–desorption analyses. Chemical activation significantly enhanced the textural properties of the material, increasing the specific surface area from 113.6 to 755.9 m² g⁻¹ and the pore volume from 0.087 to 0.442 cm³ g⁻¹ compared with biochar. FTIR analysis revealed the presence of oxygen-containing functional groups and aromatic structures that may contribute to phenol adsorption. The activated carbon produced under optimized conditions (700 °C, 30 min, and 130 μm particle size) exhibited an adsorption capacity of 57.32 mg g⁻¹. Kinetic experiments showed rapid adsorption, with equilibrium reached within approximately 60 min, and the pseudo-second-order model provided the best fit to the experimental data (R² = 0.999). Equilibrium studies demonstrated that adsorption capacity increased with temperature, reaching a Langmuir maximum adsorption capacity of 727.46 mg g⁻¹ at 55 °C. Economic analysis showed that activated carbon presented a higher production cost than biochar (24.35 versus 13.40 US$ kg⁻¹). However, its superior adsorption performance resulted in a lower performance-adjusted cost (0.516 versus 0.856 US$ g⁻¹ of phenol adsorbed). These findings demonstrate that spent hops are a promising feedstock for the production of activated carbon, contributing to both wastewater treatment and the valorization of brewing-industry residues. Full article

Selective degradation of antibiotics in complex wastewater is often hindered by the non-selective consumption of reactive oxygen species by coexisting organic matter. In this study, an adsorption-coupled heterogeneous Fenton-like strategy was developed to preferentially enrich tetracycline (TC) at the catalyst interface prior to oxidative degradation. MIL-53(Fe), MIL-101(Fe), and NH₂-MIL-101(Fe) were synthesized using a solvothermal method and systematically compared in terms of TC adsorption, catalytic degradation, and degradation selectivity in binary TC/glucose systems. Although MIL-101(Fe) exhibited the highest overall TC degradation efficiency, NH₂-MIL-101(Fe) showed the highest selectivity toward TC. At a TC/glucose concentration ratio of 2:2, NH₂-MIL-101(Fe) achieved a TC degradation selectivity of 73.1%, compared with 50.2% for MIL-101(Fe). Electron spin resonance and radical scavenging experiments demonstrated that ·OH was the dominant reactive species and that TC oxidation occurred predominantly at or near the catalyst surface. The enhanced selectivity was attributed to preferential TC adsorption followed by surface-localized oxidation and repeated adsorption–degradation cycles. Full-scan LC-MS analysis revealed several transformation-related ions, from which a tentative pathway involving possible N-demethylation, oxidative fragmentation, and ring-cleavage-related transformations was proposed; however, the individual product structures were not definitively identified. After five reuse cycles, the TC degradation efficiency remained above 75%, while the degradation selectivity decreased only from 74.7% to 68.7%. NH₂-MIL-101(Fe) also retained preferential TC removal in a TC-spiked domestic wastewater matrix. These results demonstrate that coupling preferential adsorption with localized Fenton-like oxidation provides an effective strategy for enhancing the selective removal of antibiotics from complex aqueous matrices. Full article

Shipboard cabins can contain both oil mist-dominated particulate matter and volatile organic compounds (VOCs), creating a need for compact air-cleaning systems capable of simultaneous particle and gas-phase removal. This study developed an integrated filtration–adsorption air cleaner through a performance-oriented route combining a low-resistance gradient filter with an activated-carbon packed bed. The gradient filter maintained PM_2.5 single-pass removal efficiencies above 99.99% across airflow rates of 150–650 m³/h and under inlet concentrations up to approximately 11 mg/m³, while maintaining relatively low airflow resistance. Three activated carbons were also systematically compared based on particle morphology, packed-bed characteristics, pore structure, and dynamic adsorption performance. JZT-07 showed the most favorable overall characteristics and achieved breakthrough capacities of 132, 167, and 159 mg/g for benzene, toluene, and n-heptane, respectively. The selected filtration and adsorption modules were integrated into accommodation- and machinery-cabin air cleaners and evaluated under standard-chamber and shipboard conditions. During treated voyages, average PM₁₀ and TVOC concentrations decreased by 75.3% and 66.4% in the accommodation cabin and by 65.8% and 69.6% in the machinery cabin, respectively. These results demonstrate a practical development route from component optimization to device integration and field validation for simultaneous particulate and VOC control in confined ship environments. Full article

Graphene quantum dots (GQDs) with distinct optical responses were prepared from pyrene using urea, melamine, and 2,4-pyridinedicarboxylic acid as nitrogen-containing regulators and were subsequently combined with ZIF-8 for visible-light-driven CO₂ reduction. FT-IR, Raman, XRD, optical spectroscopy, representative high-magnification transmission electron microscopy, and X-ray photoelectron spectroscopy (XPS) showed regulator-dependent structural, compositional, and optical differences. XPS detected surface nitrogen in all three GQD samples, with the highest N content in y-GQDs, while the relative N 1s component distributions differed across the series. At a nominal 4 wt% GQD addition, r-GQDs/ZIF-8 gave the highest observed mean CO and CH₄ formation rates of 23.51 ± 0.48 and 4.08 ± 0.15 μmol·g⁻¹·h⁻¹, respectively, corresponding to approximately 2.9- and 4.5-fold increases over pristine ZIF-8. This sample also showed the lowest fitted charge-transfer resistance, the highest mean photocurrent density, and the fastest qualitative time-resolved photoluminescence decay among the compared composites. Across three independent five-cycle tests, 83.78 ± 0.54% of the initial combined CO and CH₄ rate was retained. These results establish correlations among regulator identity, surface composition, optical relaxation, photoelectrochemical response, and catalytic activity, but do not determine a unique charge-transfer pathway or exclude contributions from surface basicity, CO₂ adsorption, and nominal-loading differences. Full article

Rice husk (RH) is a renewable siliceous lignocellulosic waste providing a unique, greener and less toxic alternative to conventional synthetic polymeric precursors in the production of carbon-based materials for biomedical applications. In this work we studied the porous structure of RH-lignin-based activated carbon produced in the form of honeycomb carbon monoliths and assessed their potential as hemoadsorbents for blood purification in the treatment of patients with serious medical conditions, such as kidney failure and sepsis. To determine their clinical suitability for such an application, the hemocompatibility and cytotoxicity of the monoliths were investigated using the standard ISO guidelines. The monoliths did not cause any changes in the cell viability or cell lysis. High micro/mesoporosity and surface chemistry of the initial monolith-C, N- and P-doped nanostructured carbon honeycomb monoliths were established by low-temperature nitrogen adsorption (LTNA) studies, mercury porosimetry data (MIP), SEM/EDS analysis and FT-IR spectroscopy. The micro-mesoporous, activated carbon-based filtration/adsorbent prototype devices, in the form of three-dimensional (3D) carbon matrix, functionalized with ion-exchange amino- and phosphate groups and encased in polyolefin heat shrink cable sleeve, have been developed with the capacity to remove protein-bound uremic toxins (PBUTs), such us PCS and IS, as well as inflammatory cytokines (IL-6 and IL-8) from human plasma in a flowing model system. The ammoxidized monolith-N, derived from the monolith-C, had the highest removal efficiency (40.05% for PCS, and 28.4% for IL-6). By contrast, phosphorylated monolith-P demonstrated the highest removal efficiency (54.62% for IS, and 54.4% for IL-8), whilst the monolith-C has the lowest removal efficiency for these adsorbates. These results do not correlate with the LTNA and MIP study results, suggesting that the interaction of surface chemical functional groups with the solutes play key roles in the adsorption mechanism. The ion-exchange mechanism of PBUTs and inflammatory cytokine chemisorption by the monoliths, modified with surface N- and P-containing functional groups, has been proposed. Full article

One-part geopolymer has emerged as a promising alternative to ordinary Portland cement. In this study, the effect of CaO dosage on the compressive strength of one-part geopolymers was systematically investigated, and its underlying modification mechanism was revealed via multi-scale characterizations including XRD, FTIR, TG, NMR and nitrogen adsorption–desorption. The results show that the compressive strength of the samples at all curing ages exhibits a trend of sharp initial decrease, followed by a slight rebound, and then a secondary decline with the increase in CaO dosage. All CaO-containing specimens exhibit significantly lower strengths than the CaO-free reference. Specifically, the reference sample achieves the highest 28-day compressive strength of 56.6 MPa. The strength of the sample at each curing age drops to the minimum at 5% CaO dosage, with a 28-day strength of only 17.9 MPa. Partial strength recovery of the sample is achieved at 7.5% CaO dosage. The strength deterioration is mainly attributed to the rapid hydration of CaO, which consumes free water and reactive silicon and hinders the generation of N-A-S-H gel rather than directly disrupting the aluminosilicate network. Meanwhile, the hydration products are continuously carbonated to form calcium carbonate, and the carbonation-induced volume expansion at excessive dosage may induce microcracks in the matrix that impair the structural integrity. Only at a moderate dosage of 7.5% CaO can a slight strength rebound be realized through the possible formation of C-S-H-type phases and the pore-filling effect. This study provides a theoretical basis for the material design and performance regulation of one-part geopolymers. Full article

To address the escalating demand for ultra-high-purity tungsten in advanced applications such as semiconductor targets and nuclear-grade shielding, this study synergistically coupled the processes of thermal decomposition, ammonia dissolution, and segmented evaporation crystallization. The optimal parameters for the thermal decomposition and ammonia dissolution stages were subsequently identified through systematic optimization. By independently regulating the nucleation and crystal growth processes during the crystallization of ammonium paratungstate (APT), the limitation of traditional methods, which require multiple crystallization cycles to achieve high purity, is effectively overcome. Experimental results demonstrated that under optimized conditions—thermal decomposition at ~280 °C and ammonia dissolution at 90 °C—high-purity APT (4N5 grade, total impurities < 50 ppm) was achieved in a single crystallization cycle. Furthermore, under segmented crystallization conditions (nucleation at 80 °C with a stirring speed of 1.26 m/s and growth at 90 °C with a stirring speed of 1.09 m/s), the product exhibited an average particle size of 34.43 μm and a direct recovery efficiency of 73.1%. By suppressing burst nucleation and reducing impurity adsorption, this process provides a critical technological pathway for large-scale production of ultra-high-purity tungsten materials. Full article

Background: Perfluorooctane sulfonate (PFOS) is a globally recognised persistent, bioaccumulative and toxic pollutant. Under China GB 5749-2022 and the US EPA 2024 drinking water MCL, permissible levels have fallen to 40 ng L⁻¹ and 4 ng L⁻¹, respectively, placing unprecedented demands on remediation technologies. Methods: An iron(III)–carboxylate metal–organic framework prepared from low-cost precursors (denoted MOF-LC, [Fe₃O(BDC)₃Cl]·x(solvent)) was synthesised via a one-pot solvothermal route from FeCl₃·6H₂O and terephthalic acid (H₂BDC). The material was characterised by PXRD, N₂ adsorption, FTIR, TGA, XPS, elemental analysis and ICP-OES. Adsorption performance was evaluated under varying initial concentrations, contact times, pH values, coexisting inorganic anions (Cl⁻, NO₃⁻, SO₄²⁻, HCO₃⁻, PO₄³⁻) and humic acid backgrounds, and by a panel of six water matrices. Results: MOF-LC exhibited a BET surface area of 1528 m² g⁻¹ and a dominant pore centred at 1.9 nm, which is geometrically compatible with the 1.36 nm molecular length of PFOS. Adsorption reached ≈95% of equilibrium capacity within 30 min and was best described by the pseudo-second-order model (R² = 0.998). Measured uptake reached 800.6 mg g⁻¹ at 298 K, corresponding to a Langmuir maximum capacity of 802 mg g⁻¹ (note that all adsorption experiments were conducted at mg L⁻¹ concentrations, several orders of magnitude above the regulatory limits cited above). Removal exceeded 88% across all six water matrices. PFOS removal efficiency fell from 99.2% to 85.8% over seven adsorption–regeneration cycles using a 1% NH₄Cl/methanol eluent, with 90.6% of the initial BET surface area retained and Fe leaching below 45 µg L⁻¹. Conclusions: Electrostatic, hydrophobic and pore confinement contributions are proposed as cooperative interpretations consistent with the observations. MOF-LC is identified as a technically promising laboratory-scale sorbent for PFOS removal from complex water matrices. Performance at environmentally relevant ng L⁻¹ concentrations and economic viability at scale remain to be established. Full article

Fe/Zn-modified TiO₂ photocatalysts were synthesized by the sol–gel method to investigate the influence of Fe loading, Zn loading, and calcination temperature on the degradation of food-industry pollutants. A 2³ factorial design combined with Response Surface Methodology was employed to optimize the synthesis parameters. The catalysts were characterized by N₂ adsorption–desorption, SEM/EDS, X-ray diffraction coupled with Rietveld refinement and point of zero charge analyses. The materials exhibited mesoporous structures with type IV isotherms, while Fe/Zn modification altered the crystalline phase composition and surface charge of TiO₂. Low metal loading stabilized the anatase phase, whereas higher Fe contents promoted the formation of hematite and rutile. Photocatalytic performance was evaluated through the discoloration and degradation of Red 40 and Tartrazine under natural sunlight and the degradation of cheese whey under artificial irradiation. F10Z2-400 exhibited the highest activity toward Red 40 (99.85% discoloration and 77.02% COD removal), whereas T-400 showed the best performance for tartrazine (86.25% discoloration and 87.61% COD removal). For cheese whey, F10Z10-400 achieved the highest degradation (41.01% COD removal). Reactive-species scavenging indicated that hydroxyl radicals made the predominant contribution to the discoloration of both dyes, followed by superoxide radicals and photogenerated holes. Kinetic analyses indicated that the Behnajady–Modirshahla–Ghanbery model best described the degradation process. RSM identified calcination temperature as the most influential synthesis parameter and showed that the effects of Fe and Zn loading were pollutant-dependent. No single catalyst formulation provided the best performance for all evaluated matrices. Full article

Biochar-supported rare earth oxides are herein assessed as heterogeneous catalysts for the UV-assisted Catalytic Wet Peroxide Oxidation (UV-CWPO) treatment of pharmaceuticals under mild conditions. Catalysts were synthesized by two different pyrolysis methods (activated carbon-assisted oxygen-limited pyrolysis in a muffle furnace, and inert-gas pyrolysis in a tubular furnace under nitrogen flow), and characterized by XRD, SEM, and N₂ adsorption–desorption isotherms. Their performance in assisting 385 nm UVA-LED CWPO treatment of acetaminophen (ACE), diclofenac (DCF), and metamizole (MTZ) was assessed under circumneutral pH conditions. The biochar-supported cerium-loaded catalyst prepared by oxygen-limited pyrolysis reported the highest activity, achieving 80% ACE and 70% DCF removals within 120 min of treatment, whereas MTZ was completely removed in less than 10 min, with only 16% of the removal attributable to adsorption. Superoxide radicals dominated the degradation mechanism, and photogenerated holes and hydroxyl radicals contributed moderately. Catalyst stability (minimal activity loss and negligible cerium leaching) was confirmed over five consecutive reuses. Degradation efficiency decreased ≈12–18% because of radical scavenging losses caused by the content of inorganic ions and organic matter in tap, river, and WWTP effluent waters. Treated effluents addressed lower toxicity than untreated solutions, reinforcing the environmental safety of this treatment strategy. Full article

Porous three-dimensional reduced graphene oxide (3DrGO) combines a hierarchical pore network with tunable surface chemistry, making it an attractive material for applications involving mass transport and interfacial phenomena. In this work, the pore structure and surface properties of 3DrGO were investigated using conventional and low-field nuclear magnetic resonance (NMR) techniques. Scanning electron microscopy (SEM), N₂ adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS), Carr-Purcell-Meiboom-Gill (CPMG) NMR relaxometry, and Fast Field Cycling (FFC) NMR relaxometry were employed to characterize the material over multiple length scales and probe confined liquid dynamics. While SEM and gas adsorption resolved the macro- and mesoporous structure, CPMG relaxometry revealed several confined liquid populations. Comparison of the NMR relaxation and XPS data suggested that the abundance of oxygen-containing surface groups contributes to differences between polar and nonpolar molecule-surface interactions, with stronger apparent interactions for polar liquids. The desorption behavior was consistent with nonuniform liquid coverage under partially saturated conditions. Analysis of NMR dispersion profiles further indicated a rough, chemically heterogeneous surface, highlighting the potential of low-field NMR techniques as powerful tools for correlating pore architecture, surface chemistry, and molecular dynamics in porous 3DrGO. Full article

The plastisphere critically modulates interactions among microplastics (MPs), biofilms, and trace metals under environmentally realistic conditions, governing the interfacial reactivity of plastisphere-coated microplastics. Here, we investigated cobalt (Co) adsorption onto large polypropylene (PP) primary microplastics (~4 mm) exposed for 28 days in a flow-through riverine mesocosm across a gradient of Co concentrations (0–60 µg·L⁻¹). A multi-technique analytical approach was employed, combining inductively coupled plasma mass spectrometry (ICP-MS), laser ablation ICP-MS (LA-ICP-MS), quantitative PCR (qPCR), and scanning electron microscopy (SEM). Cobalt accumulation increased linearly with time, consistent with apparent first-order dependence on aqueous Co concentration under constant exposure, reaching 38 ± 3 mg·kg⁻¹ after 28 days at 60 µg·L⁻¹, with no saturation observed. The concentration-dependent Co accumulation was well described by an empirical power-law model (Q = KC₀ⁿ), with the empirical coefficient K increasing linearly over time, reflecting the progressive increase in Co accumulation at a given aqueous concentration. Microbial colonization developed rapidly on MPs, with 16S and 18S rRNA gene copy numbers stabilizing after 14 days, while surface-normalized Co signals increased sharply after day 21, indicating a time-dependent modification of biofilm properties influencing Co retention. SEM confirmed complex microbial structures, including diatom-like cells. No cobalt adsorption was observed under sterile conditions, confirming the key role of biofilm presence. These findings highlight the dynamic role of the plastisphere as a chemically and biologically active interface under environmentally realistic riverine conditions, with implications for contaminant fate, bioavailability, and risk assessment in freshwater systems affected by plastic pollution. Full article

Boron (B)-modified SnO₂ samples with various B concentrations (1, 2, and 5 at%) were successfully synthesized using the sol–gel method. The effect of the B/SnO₂ molar ratio on the crystal structure, microstructure, optical, and photocatalytic properties was investigated. The samples were characterized by X-ray diffraction (XRD), N₂ adsorption–desorption experiments, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Diffuse reflectance UV–Vis (DR UV–Vis) and photoluminescence (PL) spectroscopy. A decrease in particle size was observed with increasing B concentration. The B-doped samples exhibited a higher fraction of microporosity and a larger specific surface area than those of undoped SnO₂. FTIR spectra display characteristic absorption of B species. The band gap values were lower than that of bulk SnO₂, and the PL results indicated a reduced electron–hole recombination rate upon boron doping. The presence of defects, such as oxygen vacancies, is highlighted. The nanoparticles exhibited excellent photocatalytic activity toward the degradation of crystal violet (CV) dye, achieving a removal efficiency under UV irradiation of over 90% for the 5 at% B-doped SnO₂ sample after 90 min. Full article

Methane production from water-bearing coal reservoirs is governed not only by methane adsorption capacity but also by the accessibility of adsorption domains and the efficiency of pore-scale transport during pressure depletion. However, the interfacial mechanism by which coal wettability and water occurrence regulate methane adsorption–desorption reversibility remains insufficiently understood. In this study, three representative Ordos Basin coal samples with different pore structures and surface polarities, denoted as OBC-L, OBC-M, and OBC-H, were investigated to explore the pore-scale mechanisms governing water-mediated methane storage and release rather than to establish basin-wide statistical relationships. A combined experimental workflow involving N₂ adsorption–desorption, FTIR and XPS analyses, contact angle and Zeta potential measurements, low-field NMR, high-pressure methane adsorption–desorption tests, kinetic modeling, hysteresis evaluation, and Pearson correlation analysis was used to clarify the coupling among pore structure, coal–water interfacial properties, water occurrence, methane storage, and methane release. The results show that OBC-H possesses the strongest dry-state methane storage potential, with the BET surface area increasing from 5.82 m²/g for OBC-L to 12.94 m²/g for OBC-H and the fitted Langmuir volume (V_L) reaching 22.3 cm³/g. Nevertheless, OBC-H also shows stronger water affinity, as reflected by an increase in the XPS-derived O/C atomic ratio from 0.118 to 0.186, a decrease in contact angle from 82.6° to 51.8°, and an increase in bound water fraction from 46.3% to 69.4%. With the transition from dry to saturated conditions, the fitted V_L of OBC-H decreases from 22.3 to 15.2 cm³/g, while the Langmuir pressure (P_L) increases from 1.38 to 3.00 MPa, indicating a simultaneous reduction in the model-estimated maximum methane adsorption capacity and apparent methane affinity. More importantly, the desorption results demonstrate that high adsorption capacity does not necessarily correspond to high methane deliverability. For OBC-H, the final desorption efficiency decreases from 79.6% to 54.2%, the effective diffusion coefficient decreases from 2.74 × 10⁻¹¹ to 0.86 × 10⁻¹¹ m²/s, and the hysteresis index increases from 12.8% to 36.4% under saturated water conditions. Correlation analysis further confirms that bound water fraction is positively associated with adsorption–desorption hysteresis but negatively associated with desorption efficiency, desorption rate constant, and effective diffusion coefficient. These findings are consistent with two distinct water-mediated constraints: adsorbed/bound interfacial water contributes to surface-site shielding, whereas capillary and saturated water occupation contributes to pore-throat transport restriction; together, these effects reduce methane release efficiency and enhancing desorption irreversibility. This study provides an interfacial interpretation of methane deliverability based on representative water-bearing coal samples and offers a mechanistic basis for understanding wettability- and water-retention-related transport constraints; broader applicability across the Ordos Basin requires validation using a larger number of samples from different coal seams and reservoir settings. Full article