Search Results (1,926)

The incorporation of waste polyethylene terephthalate (PET) as a modifier for asphalt presents a promising approach to addressing the environmental pollution associated with waste plastics while simultaneously extending the service life of road surfaces. This study investigates the fundamental physical properties and rheological properties of asphalt modified with waste PET at both high and low temperatures. Utilizing the theory of fractional derivatives, performance evaluation indicators, such as the deformation factor and viscoelasticity factor, have been developed for the assessment of waste PET-modified asphalt. The underlying mechanism of this modification was examined through scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicate that the addition of waste PET enhances the high-temperature stability of the base asphalt but reduces its resistance to cracking at low temperatures. The fractional derivative model effectively describes the dynamic shear rheological properties of waste PET-modified asphalt, achieving a maximum correlation coefficient of 0.99991. Considering the performance of modified asphalt at both high and low temperatures, the optimal concentration of waste PET was determined to be 6%. At this concentration, the minimum creep stiffness of the PET-modified asphalt was approximately 155 MPa at −6 °C. Additionally, the rutting factor of the waste PET-modified asphalt achieved a maximum value of 527.12 KPa at 52 °C. The interaction between waste PET and base asphalt was primarily physical, with mutual adsorption leading to the formation of a spatial network structure that enhanced the deformation resistance of the asphalt. This study provides a theoretical foundation and technical support for the engineering application of waste PET as a modifier in asphalt. Full article

The removal of high-concentration m-cresol from industrial wastewater remains a significant challenge due to its toxicity and persistence. In this study, a commercially available functionalized resin with a high BET surface area (1439 m² g⁻¹) and hierarchical pore structure was employed for the adsorption of pure m-cresol at an initial concentration of 20 g L⁻¹, representative of coal-based industrial effluents. Comprehensive characterization confirmed the presence of oxygen-rich functional groups, amorphous polymeric structure, and uniform surface morphology conducive to adsorption. Batch experiments were conducted to evaluate the effects of resin dosage, contact time, temperature, and equilibrium concentration. Under optimized conditions (0.15 g resin, 60 °C), a maximum adsorption capacity of 556.3 mg g⁻¹ and removal efficiency of 71% were achieved. Kinetic analysis revealed that the pseudo-second-order model best described the adsorption process (R² > 0.99). Isotherm data fit the Langmuir model most closely (R² = 0.9953), yielding a monolayer capacity of 833.3 mg g⁻¹. Thermodynamic analysis showed that adsorption was spontaneous (ΔG° < 0), endothermic (ΔH° = 7.553 kJ mol⁻¹), and accompanied by increased entropy (ΔS° = 29.90 J mol⁻¹ K⁻¹). The good agreement with the PSO model is indicative of chemisorption, as supported by other lines of evidence, including thermodynamic parameters (e.g., positive ΔH° and ΔS°), surface functional group characteristics, and molecular interactions. The adsorption mechanism was elucidated through comprehensive modeling of adsorption kinetics, isotherms, and thermodynamics, combined with detailed physicochemical characterization of the resin prior to adsorption, reinforcing the mechanistic understanding of m-cresol–resin interactions. Full article

High-performance hydrogen gas sensors have gained considerable interest for their crucial function in reducing H₂ explosion risk. Although MoS₂ has good potential for chemical sensing, its application in hydrogen detection at room temperature is limited by slow response and incomplete recovery. In this work, Pd-doped MoS₂ thin films are deposited on a Si substrate, forming Pd-doped MoS₂/Si heterojunctions via magnetron co-sputtering. The incorporation of Pd nanoparticles significantly enhances the catalytic activity for hydrogen adsorption and facilitates more efficient electron transfer. Owing to its distinct structural characteristics and sharp interface properties, the fabricated Pd-doped MoS₂/Si heterojunction device exhibits excellent H₂ sensing performance under room temperature conditions. The gas sensor device achieves an impressive sensing response of ~6.4 × 10³% under 10,000 ppm H₂ concentration, representing a 110% improvement compared to pristine MoS₂. Furthermore, the fabricated heterojunction device demonstrates rapid response and recovery times (24.6/12.2 s), excellent repeatability, strong humidity resistance, and a ppb-level detection limit. These results demonstrate the promising application prospects of Pd-doped MoS₂/Si heterojunctions in the development of advanced gas sensing devices. Full article

Pseudo-persistent organic pollutants, such as pharmaceuticals, personal care products (PPCPs), and organic dyes, are a major issue in current environmental engineering. Considering the limitations of traditional wastewater treatment plant methods and degradation technologies for organic pollutants, the search for new technologies more suitable for treating these new types of pollutants has become a research hotspot in recent years. Membrane filtration, adsorption, advanced oxidation, and electrochemical advanced oxidation technologies can effectively treat new organic pollutants. The electro-advanced oxidation process based on sulfate radicals is renowned for its non-selectivity, high efficiency, and environmental friendliness, and it can improve the dewatering performance of sludge after wastewater treatment. Therefore, in this study, octyl methoxycinnamate (OMC) was selected as the target pollutant. A new type of electrochemical filtration device based on the advanced oxidation process of sulfate radicals was designed, and a new type of modified carbon nanotube material electrode was synthesized to enhance its degradation effect. In a mixed system of water and acetonitrile, the efficiency of the electrochemical filtration device loaded with the modified electrode for degrading OMC is 1.54 times that at room temperature. The experimental results confirmed the superiority and application prospects of the self-designed treatment scheme for organic pollutants, providing experience and a reference for the future treatment of PPCP pollution. Full article

Deep marine shale is the primary carrier of shale gas resources in Southwestern China. Because the occurrence and gas content of methane vary with burial conditions, understanding the microscopic mechanism of methane occurrence in deep marine shale is critical for effective shale gas exploitation. The temperature and pressure conditions in deep shale exceed the operating limits of experimental equipment; thus, few studies have discussed the microscopic occurrence mechanism of shale gas in deep marine shale. This study applies molecular simulation technology to reveal the methane’s microscopic occurrence mechanism, particularly the main controlling factor of adsorbed methane in deep marine shale. Two types of simulation models are also proposed. The Grand Canonical Monte Carlo (GCMC) method is used to simulate the adsorption behavior of methane molecules in these two models. The results indicate that the isosteric adsorption heat of methane in both models is below 42 kJ/mol, suggesting that methane adsorption in deep shale is physical adsorption. Adsorbed methane concentrates on the pore wall surface and forms a double-layer adsorption. Furthermore, adsorbed methane can transition to single-layer adsorption if the pore size is less than 1.6 nm. The total adsorption capacity increases with rising pressure, although the growth rate decreases. Excess adsorption capacity is highly sensitive to pressure and can become negative at high pressures. Methane adsorption capacity is determined by pore size and adsorption potential, while accommodation space and adsorption potential are influenced by pore size and mineral type. Under deep marine shale reservoir burial conditions, with burial depth deepening, the effect of temperature on shale gas occurrence is weaker than pressure. Higher temperatures inhibit shale gas occurrence, and high pressure enhances shale gas preservation. Smaller pores facilitate the occurrence of adsorbed methane, and larger pores have larger total methane adsorption capacity. Deep marine shale with high formation pressure and high clay mineral content is conducive to the microscopic accumulation of shale gas in deep marine shale reservoirs. This study discusses the microscopic occurrence state of deep marine shale gas and provides a reference for the exploration and development of deep shale gas. Full article

Carbon monoxide (CO) is a major toxic gas emitted from vehicle exhaust, industrial processes, and incomplete fuel combustion, posing serious environmental and health risks. Catalytic oxidation of CO into less harmful CO₂ is an effective strategy to reduce these emissions. In this study, we investigated the catalytic performance of platinum (Pt) single atoms doped on C₃N monolayers with various vacancy defects, including single carbon (C_V) and nitrogen (N_V) vacancies, using density functional theory (DFT) calculations. Our results demonstrate that Pt@N_V-C₃N exhibited the most favorable catalytic properties, with the highest O₂ adsorption energy (−3.07 eV). This performance significantly outperforms Pt atoms doped at other vacancies. It can be attributed to the strong binding between Pt and nitrogen vacancies, which contributes to its excellent resistance to Pt aggregation. CO oxidation on Pt@N_V-C₃N proceeds via the Eley–Rideal (ER2) mechanism with a low activation barrier of 0.41 eV for the rate-determining step, indicating high catalytic efficiency at low temperatures. These findings suggest that Pt@N_V-C₃N is a promising candidate for CO oxidation, contributing to developing cost-effective and environmentally sustainable catalysts. The strong binding of Pt atoms to the nitrogen vacancies prevents aggregation, ensuring the stability and durability of the catalyst. The kinetic modeling further revealed that the ER2 mechanism offers the highest reaction rate constants over a wide temperature range (273–700 K). The low activation energy barrier also facilitates CO oxidation at lower temperatures, addressing critical challenges in automotive and industrial pollution control. This study provides valuable theoretical insights for designing advanced single-atom catalysts for environmental remediation applications. Full article

The overall efficiency of combining denitrification and volatile organic compound (VOC) removal through selective catalytic reduction (SCR) technology is currently mainly limited by the VOC removal aspect. However, existing studies have not studied the microscopic mechanism of the interaction between VOCs and catalysts, failing to provide a theoretical basis for catalysts. Therefore, this work explored the interaction mechanisms between SCR catalysts doped with different additives and typical VOCs (acetone and toluene) in flue gas based on density functional theory (DFT) calculations. The results showed that the VNi-TiO₂ surface exhibited a high adsorption energy of −0.80 eV for acetone and a high adsorption energy of −1.02 eV for toluene on the VMn-TiO₂ surface. Electronic structure analysis revealed the VMn-TiO₂ and VNi-TiO₂ surfaces exhibited more intense orbital hybridization with acetone and toluene, promoting charge transfer between the two and resulting in stronger interactions. The analysis of temperature on adsorption free energy showed that VMn-TiO₂ and VNi-TiO₂ still maintained high activity at high temperatures. This work contributes to clarifying the interaction mechanism between SCR and VOCs and enhancing the VOC removal efficiency. Full article

This study analyzed the heavy metal tolerance and chromium reduction and the potential of plant growth to promote Rhizobium sp. OS-1. By genetic makeup, the Rhizobium strain is nitrogen-fixing and phosphate-solubilizing in metal-contaminated agricultural soil. Among the Rhizobium group, bacterial strain OS-1 showed a significant tolerance to heavy metals, particularly chromium (900 µg/mL), zinc (700 µg/mL), and copper. In the initial investigation, the bacteria strains were morphologically short-rod, Gram-negative, appeared as light pink colonies on media plates, and were biochemically positive for catalase reaction and the ability to ferment glucose, sucrose, and mannitol. Further, bacterial genomic DNA was isolated and amplified with the 16SrRNA gene and sequencing; the obtained 16S rRNA sequence achieved accession no. HE663761.1 from the NCBI GenBank, and it was confirmed that the strain belongs to the Rhizobium genus by phylogenetic analysis. The strain’s performance was best for high hexavalent chromium [Cr(VI)] reduction at 7–8 pH and a temperature of 30 °C, resulting in a total decrease in 96 h. Additionally, the adsorption isotherm Freundlich and Langmuir models fit best for this study, revealing a large biosorption capacity, with Cr(VI) having the highest affinity. Further bacterial chromium reduction was confirmed by an enzymatic test of nitro reductase and chromate reductase activity in bacterial extract. Further, from the metal biosorption study, an Artificial Neural Network (ANN) model was built to assess the metal reduction capability, considering the variables of pH, temperature, incubation duration, and initial metal concentration. The model attained an excellent expected accuracy (R² > 0.90). With these features, this bacterial strain is excellent for bioremediation and use for industrial purposes and agricultural sustainability in metal-contaminated agricultural fields. Full article

The commercialization of proton-conducting fuel cells (PCFCs) is hindered by the limited electroactivity and durability of cathodes at intermediate temperatures ranging from 400 to 700 °C, a challenge exacerbated by an insufficient understanding of high-entropy perovskite (HEP) materials for oxygen reduction reaction (ORR) optimization. This study introduces an yttrium-doped HEP to address these limitations. A comparative analysis of Ce_0.2−xY_xBa_0.2Sr_0.2La_0.2Ca_0.2CoO_3−δ (x = 0, 0.2; designated as CBSLCC and YBSLCC) revealed that yttrium doping enhanced the ORR activity, reduced the thermal expansion coefficient (19.9 × 10⁻⁶ K⁻¹, 30–900 °C), and improved the thermomechanical compatibility with the BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ electrolytes. Electrochemical testing demonstrated a peak power density equal to 586 mW cm⁻² at 700 °C, with a polarization resistance equaling 0.3 Ω cm². Yttrium-induced lattice distortion promotes proton adsorption while suppressing detrimental Co spin-state transitions. These findings advance the development of durable, high-efficiency PCFC cathodes, offering immediate applications in clean energy systems, particularly for distributed power generation. Full article

The recovery and abatement of volatile organic compounds (VOCs) have received increasing attention due to their significant environmental and health impacts. Supported sulfonic acid materials have shown great potential in converting aromatic VOCs into their non-volatile derivatives through reactive adsorption. However, the anchoring state of sulfonic acid groups, which is closely related to the properties of the support, greatly affects their performance. In this study, two supported sulfonic acid materials, SZO and SMO, were prepared by treating ZrO₂ and MgO with chlorosulfonic acid, respectively, to investigate the influence of the support properties on the anchoring state of sulfonic acid groups and their reactive adsorption performance for o-xylene. The supports, adsorbents, and adsorption products were extensively characterized, and the reactivity of SZO and SMO towards o-xylene was systematically compared. The results showed that sulfonic acid groups are anchored on the ZrO₂ surface through covalent bonding, forming positively charged sulfonic acid sites ([O_1.5Zr-O]^δ−-SO3H^δ+) with a loading of 3.6 mmol/g. As a result, SZO exhibited excellent removal efficiency (≥91.3%) and high breakthrough adsorption capacity (ranging from 38.59 to 82.07 mg/g) for o-xylene in the temperature range of 130 –150 °C. In contrast, sulfonic acid groups are anchored on the MgO surface via ion-paired bonding, leading to the formation of negatively charged sulfonic acid sites ([O_0.5Mg]⁺:OSO₃H⁻), which prevents their participation in the electrophilic sulfonation reaction with o-xylene molecules. This work provides new insights into tuning and enhancing the performance of supported sulfonic acid materials for the resource-oriented treatment of aromatic VOCs. Full article

In wet flue gas desulfurization and denitrification processes, nitrite accumulation inhibits denitrification efficiency and induces secondary pollution due to its acidic disproportionation. This study developed a Mn-modified ZSM-5 zeolite catalyst, achieving efficient resource conversion of nitrite in nitrogen-containing wastewater through an O₃ + Mn/ZSM-5 catalytic system. Mn/ZSM-5 catalysts with varying SiO₂/Al₂O₃ ratios (prepared by wet impregnation) were characterized by BET, XRD, and XPS. Experimental results demonstrated that Mn/ZSM-5 (SiO₂/Al₂O₃ = 400) exhibited a larger specific surface area, enhanced adsorption capacity, abundant surface Mn³⁺/Mn⁴⁺ species, hydroxyl oxygen species, and chemisorbed oxygen, leading to superior oxidation capability and catalytic activity. Under the optimized conditions of reaction temperature = 40 °C, initial pH = 4, Mn/ZSM-5 dosage = 1 g/L, and O₃ concentration = 100 ppm, the $\mathrm{N}{\mathrm{O}}_2^{-}$ oxidation efficiency reached 94.33%. Repeated tests confirmed that the Mn/ZSM-5 catalyst exhibited excellent stability and wide operational adaptability. The synergistic effect between Mn species and the zeolite support significantly improved ozone utilization efficiency. The O₃ + Mn/ZSM-5 system required less ozone while maintaining high oxidation efficiency, demonstrating better cost-effectiveness. Mechanism studies revealed that the conversion pathway of $\mathrm{N}{\mathrm{O}}_2^{-}$ followed a dual-path catalytic mechanism combining direct ozonation and free radical chain reactions. Practical spray tests confirmed that coupling the Mn/ZSM-5 system with ozone oxidation flue gas denitrification achieved over 95% removal of liquid-phase $\mathrm{N}{\mathrm{O}}_2^{-}$ byproducts without compromising the synergistic removal efficiency of NO_x/SO₂. This study provided an efficient catalytic solution for industrial wastewater treatment and the resource utilization of flue gas denitrification byproducts. Full article

Depending on the feedstock type and the pyrolysis conditions, biochars exhibit different physical, chemical, and structural properties, which highly influence their performance in various applications. This study presents a comprehensive characterization of biochar materials derived from the waste wood of pine (Pinus sylvestris L.) and beech (Fagus sylvatica) after low-temperature pyrolysis at 270 °C, followed by chemical activation using zinc chloride. The resulting materials were thoroughly analyzed in terms of their chemical composition (FTIR), thermal behavior (TGA/DTG), structural morphology (SEM and XRD), elemental analysis, and particle size distribution. The successful modification of raw biomass into carbon-rich structures of increased aromaticity and thermal stability was confirmed. Particle size analysis revealed that the activated carbon of Fagus sylvatica (FSAC) exhibited a monomodal distribution, indicating high homogeneity, whereas Pinus sylvestris-activated carbon showed a distinct bimodal distribution. This heterogeneity was supported by elemental analysis, revealing a higher inorganic content in pine-activated carbon, likely contributing to its dimensional instability during activation. These findings suggest that the uniform morphology of beech-activated carbon may be advantageous in filtration and adsorption applications, while pine-activated carbon’s heterogeneous structure could be beneficial for multifunctional systems requiring variable pore architectures. Overall, this study underscored the potential of chemically activated biochar from lignocellulosic residues for customized applications in environmental and material science domains. Full article

The development of deep coalbed methane (buried depth > 2000 m) in the Yan’an block of Ordos Basin is limited by low permeability, the pore structure of the coal reservoir, and the gas–water occurrence relationship. It is urgent to clarify the key control mechanism of pore structure on gas migration. In this study, based on high-pressure mercury intrusion (pore size > 50 nm), low-temperature N₂/CO₂ adsorption (0.38–50 nm), low-field nuclear magnetic resonance technology, fractal theory and Pearson correlation coefficient analysis, quantitative characterization of multi-scale pore–fluid system was carried out. The results show that the multi-scale pore network in the study area jointly regulates the occurrence and migration process of deep coalbed methane in Yan’an through the ternary hierarchical gas control mechanism of ‘micropore adsorption dominant, mesopore diffusion connection and macroporous seepage bottleneck’. The fractal dimensions of micropores and seepage are between 2.17–2.29 and 2.46–2.58, respectively. The shape of micropores is relatively regular, the complexity of micropore structure is low, and the confined space is mainly slit-like or ink bottle-like. The pore-throat network structure is relatively homogeneous, the difference in pore throat size is reduced, and the seepage pore shape is simple. The bimodal structure of low-field nuclear magnetic resonance shows that the bound fluid is related to the development of micropores, and the fluid mobility mainly depends on the seepage pores. Pearson’s correlation coefficient showed that the specific surface area of micropores was strongly positively correlated with methane adsorption capacity, and the nanoscale pore-size dominated gas occurrence through van der Waals force physical adsorption. The specific surface area of mesopores is significantly positively correlated with the tortuosity. The roughness and branch structure of the inner surface of the channel lead to the extension of the migration path and the inhibition of methane diffusion efficiency. Seepage porosity is linearly correlated with gas permeability, and the scale of connected seepage pores dominates the seepage capacity of reservoirs. This study reveals the pore structure and ternary grading synergistic gas control mechanism of deep coal reservoirs in the Yan’an Block, which provides a theoretical basis for the development of deep coalbed methane. Full article

Excessive phosphate from agriculture and industry has led to widespread eutrophication, posing a serious environmental threat. To address this issue, metal-modified biochars have emerged as promising adsorbents due to their high affinity for phosphate ions. This study investigates the application of two magnesium-modified biochar hydrogels denoted as magnesium–bamboo biochar hydrogel (Mg-BBH) and magnesium–pulp biochar hydrogel (Mg-PBH) for phosphate recovery from aqueous solutions, with an additional aim as slow-release fertilizers. The adsorbents were synthesized by impregnating Mg-modified biochars into sodium-alginate-based hydrogel. The influence of initial phosphate concentration, contact time, and temperature were investigated to determine optimal adsorption conditions. Both adsorbents exhibited excellent adsorption performance, with maximum capacities of 309.96 mg PO₄/g (Mg-BBH) and 234.69 mg PO₄/g (Mg-PBH). Moreover, the adsorption performance of the adsorbents was greatly influenced by the magnesium content. The adsorption process followed the Temkin isotherm and pseudo-second-order kinetics, suggesting that the adsorption energy decreases proportionally with surface coverage and the phosphate uptake was governed by chemisorption. Thermodynamic study confirmed the process was spontaneous and endothermic at 40 °C. A slow-release study further demonstrated a great release of phosphate in soil over time. These findings highlight the dual functionality of Mg-BBH and Mg-PBH as effective materials for both phosphate recovery and controlled nutrient delivery, contributing to sustainable phosphate management. Full article

Direct air capture (DAC), as a complementary strategy to carbon capture and storage (CCS), offers a scalable and sustainable pathway to remove CO₂ directly from the ambient air. This study presents a detailed evaluation of the amine-functionalised metal-organic framework (MOF) sorbent, mmen-Mg₂(dobpdc), for DAC using a temperature–vacuum swing adsorption (TVSA) process. While this sorbent has demonstrated promising performance in point-source CO₂ capture, this is the first dynamic simulation-based study to rigorously assess its effectiveness for low-concentration atmospheric CO₂ removal. A transient one-dimensional TVSA model was developed in Aspen Adsorption and validated against experimental breakthrough data to ensure accuracy in capturing both the sharp and gradual adsorption kinetics. To enhance process efficiency and sustainability, this work provides a comprehensive parametric analysis of key operational factors, including air flow rate, temperature, adsorption/desorption durations, vacuum pressure, and heat exchanger temperature, on process performance, including CO₂ purity, recovery, productivity, and specific energy consumption. Under optimal conditions for this sorbent (vacuum pressure lower than 0.15 bar and feed temperature below 15 °C), the TVSA process achieved ~98% CO₂ purity, recovery over 70%, and specific energy consumption of about 3.5 MJ/KgCO₂. These findings demonstrate that mmen-Mg₂(dobpdc) can achieve performance comparable to benchmark DAC sorbents in terms of CO₂ purity and recovery, underscoring its potential for scalable DAC applications. This work advances the development of energy-efficient carbon removal technologies and highlights the value of step-shape isotherm adsorbents in supporting global carbon-neutrality goals. Full article