Search Results (841)

An ultrasonic-enhanced hydrogen peroxide water-washing process was developed to recover lead from raw flue dust (RFD) under neutral conditions. At optimal parameters (40 °C, 30 min, 4 mL H₂O₂, liquid-to-solid ratio 2:1, 240 W ultrasound), the Pb mass fraction in the solid residue increased from 41.68% in the RFD to 68.11%, accompanied by a Pb recovery rate of 97.1%. These values are significantly higher than those obtained under identical conditions without ultrasound (64.07% and 95.93%, respectively). Ultrasound promotes de-agglomeration and generates •OH radicals that accelerate the oxidation of PbSO₃ to insoluble PbSO₄ while concurrently removing impurity cadmium. This research offers a green and efficient alternative to traditional lead recovery methods, fostering sustainable development in the metallurgical industry. Full article

The sustainable recovery of valuable metals such as Cu and Co from ores is a pressing need considering environmental and economic challenges. Therefore, this study evaluates the effectiveness of deep eutectic solvents (DESs) as alternative leaching agents for Cu and Co extraction. Four DESs were prepared using choline chloride (ChCl) as a hydrogen bond acceptor (HBA) and oxalic acid (OA), ethylene glycol (EG), urea (U) and thiourea (TU) as hydrogen bond donors (HBDs). Leaching experiments were conducted with DESs supplemented with 30 wt.% water at varying temperatures, various solid-to-liquid ratios, and time durations. The ChCl:OA DES demonstrated the highest leaching efficiencies among the DESs tested on pure CuO and CoO, achieving 89.2% for Cu and 92.4% for Co (60 °C, 400 rpm, 6 h, −75 + 53 µm particle size, and 1:10 solid-to-liquid ratio). In addition, the dissolution kinetics, analysed using the shrinking core model (SCM), showed that the leaching process was mainly controlled by surface chemical reactions. The activation energy values for Cu and Co leaching were 46.8 kJ mol⁻¹ and 51.4 kJ mol⁻¹, respectively, supporting a surface chemical control mechanism. The results highlight the potential of ChCl:OA as a sustainable alternative for metal recovery. Full article

This study explores the self-healing properties of polyurethane nanocomposites enhanced by multiple hydrogen bonds from ureido-pyrimidinone and the incorporation of 1–3 wt.% graphene nanoparticles, based on polyol α,ω-dihydroxy[oligo(butylene-ethylene adipate)]diol, which, according to our knowledge, has not been previously used in such systems. These new materials were synthesized via a two-step process and characterized by their thermal, mechanical, chemical, and self-healing properties. The mechanical analysis revealed that all nanocomposites exhibited high self-healing efficiencies (88–91%). The PU containing 2% graphene stands out as it exhibits the highest initial mechanical strength of ~5 MPa compared to approximately 2MP for a pristine PU while maintaining excellent self-healing efficiency (88%). A cut on the PU nanocomposite with 2% graphene can be completely healed after being heated at 80 °C for 1 h, which shows that it has a fast recovery time. Moreover, 3D printing was also successfully used to assess their processability and its effect on self-healing behavior. Three-dimensional printing did not negatively affect the material regeneration properties; thus, the material can be used in a variety of applications as expected in terms of dimensions and geometry. Full article

As a crucial reactive oxygen species, hydrogen peroxide (H₂O₂) serves as both a physiological regulator and a pathological indicator in human systems. Its urinary concentration has emerged as a valuable biomarker for assessing metabolic disorders and renal function. While conventional colorimetric determination methods predominantly employ enzymatic or nanozyme catalysts, we present an innovative non-catalytic approach utilizing the redox-responsive properties of organic neutral radicals. Specifically, we designed and synthesized a novel radical TTM-DMODPA based on the tris (2,4,6-trichlorophenyl) methyl (TTM) scaffold, which exhibits remarkable optical tunability and oxidative sensitivity. This system enables dual-mode H₂O₂ quantification: (1) UV-vis spectrophotometry (linear range: 2.5–250 μmol/L, LOD: 1.275 μmol/L) and (2) smartphone-based visual analysis (linear range: 2.5–250 μmol/L, LOD: 3.633 μmol/L), the latter being particularly suitable for point-of-care testing. Validation studies using urine samples demonstrated excellent recovery rates (96–104%), confirming the method’s reliability for real-sample applications. Our work establishes a portable, instrument-free platform for urinary H₂O₂ determination, with significant potential in clinical diagnostics and environmental monitoring. Full article

With increasing global challenges related to water scarcity and phosphorus depletion, the recovery and reuse of wastewater-derived nutrients offer a sustainable path forward. This study evaluates the dual role of lanthanides (Ce³⁺ and La³⁺) in recovering phosphorus from municipal wastewater and supporting corn (Zea mays) cultivation through lanthanide phosphate (Ln-P) and lanthanide-reclaimed wastewater (LRWW, wastewater spiked with lanthanide). High-purity precipitates of CePO₄ (98%) and LaPO₄ (92%) were successfully obtained without pH adjustment, as confirmed by X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectroscopy (EDS). Germination assays revealed that lanthanides, even at concentrations up to 2000 mg/L, did not significantly alter germination rates compared to traditional coagulants, though root and shoot development declined above this threshold—likely due to reduced hydrogen peroxide (H₂O₂) production and elevated total dissolved solids (TDSs), which induced physiological drought. Greenhouse experiments using desert-like soil amended with Ln-P and irrigated with LRWW showed no statistically significant differences in corn growth parameters—including plant height, stem diameter, leaf number, leaf area, and biomass—when compared to control treatments. Photosynthetic performance, including stomatal conductance, quantum efficiency, and chlorophyll content, remained unaffected by lanthanide application. Metal uptake analysis indicated that lanthanides did not inhibit phosphorus absorption and even enhanced the uptake of calcium and magnesium. Minimal lanthanide accumulation was detected in plant tissues, with most retained in the root zone, highlighting their limited mobility. These findings suggest that lanthanides can be safely and effectively used for phosphorus recovery and agricultural reuse, contributing to sustainable nutrient cycling and aligning with the United Nations’ Sustainable Development Goals of zero hunger and sustainable cities. Full article

Rail transit as a high-energy consumption field urgently requires the adoption of clean energy innovations to reduce energy consumption and accelerate the transition to new energy applications. As an energy-saving fluid machinery, the ejector exhibits significant application potential and academic value within this field. This paper reviewed the recent advances, technical challenges, research hotspots, and future development directions of ejector applications in rail transit, aiming to address gaps in existing reviews. (1) In waste heat recovery, exhaust heat is utilized for propulsion in vehicle ejector refrigeration air conditioning systems, resulting in energy consumption being reduced by 12~17%. (2) In vehicle pneumatic pressure reduction systems, the throttle valve is replaced with an ejector, leading to an output power increase of more than 13% and providing support for zero-emission new energy vehicle applications. (3) In hydrogen supply systems, hydrogen recirculation efficiency exceeding 68.5% is achieved in fuel cells using multi-nozzle ejector technology. (4) Ejector-based active flow control enables precise ± 20 N dynamic pantograph lift adjustment at 300 km/h. However, current research still faces challenges including the tendency toward subcritical mode in fixed geometry ejectors under variable operating conditions, scarcity of application data for global warming potential refrigerants, insufficient stability of hydrogen recycling under wide power output ranges, and thermodynamic irreversibility causing turbulence loss. To address these issues, future efforts should focus on developing dynamic intelligent control technology based on machine learning, designing adjustable nozzles and other structural innovations, optimizing multi-system efficiency through hybrid architectures, and investigating global warming potential refrigerants. These strategies will facilitate the evolution of ejector technology toward greater intelligence and efficiency, thereby supporting the green transformation and energy conservation objectives of rail transit. Full article

Gasification of municipal solid waste and other biogenic residues (e.g., biomass and biowaste) is increasingly recognized as a promising thermochemical pathway for converting non-recyclable fractions into valuable energy carriers, with applications in electricity generation, district heating, hydrogen production, and synthetic fuels. This paper provides a comprehensive analysis of major gasification technologies, including fixed bed, fluidized bed, entrained flow, plasma, supercritical water, microwave-assisted, high-temperature steam, and rotary kiln systems. Key aspects such as feedstock compatibility, operating parameters, technology readiness level, and integration within circular economy frameworks are critically evaluated. A comparative assessment of incineration and pyrolysis highlights the environmental and energetic advantages of gasification. The valorization pathways for main product (syngas) and by-products (syngas, ash, tar, and biochar) are also explored, emphasizing their reuse in environmental, agricultural, and industrial applications. Despite progress, large-scale adoption in Europe is constrained by economic, legislative, and technical barriers. Future research should prioritize scaling emerging systems, optimizing by-product recovery, and improving integration with carbon capture and circular energy infrastructures. Supported by recent European policy frameworks, gasification is positioned to play a key role in sustainable waste-to-energy strategies, biomass valorization, and the transition to a low-emission economy. Full article

Against the backdrop of global energy transition and strict environmental regulations, supercritical carbon dioxide (scCO₂) fracturing and oil displacement technologies have emerged as pivotal green approaches in shale gas exploitation, offering the dual advantages of zero water consumption and carbon sequestration. However, the inherent low viscosity of scCO₂ severely restricts its sand-carrying capacity, fracture propagation efficiency, and oil recovery rate, necessitating the urgent development of high-performance thickeners. The current research on scCO₂ thickeners faces a critical trade-off: traditional fluorinated polymers exhibit excellent philicity CO₂, but suffer from high costs and environmental hazards, while non-fluorinated systems often struggle to balance solubility and thickening performance. The development of new thickeners primarily involves two directions. On one hand, efforts focus on modifying non-fluorinated polymers, driven by environmental protection needs—traditional fluorinated thickeners may cause environmental pollution, and improving non-fluorinated polymers can maintain good thickening performance while reducing environmental impacts. On the other hand, there is a commitment to developing non-noble metal-catalyzed siloxane modification and synthesis processes, aiming to enhance the technical and economic feasibility of scCO₂ thickeners. Compared with noble metal catalysts like platinum, non-noble metal catalysts can reduce production costs, making the synthesis process more economically viable for large-scale industrial applications. These studies are crucial for promoting the practical application of scCO₂ technology in unconventional oil and gas development, including improving fracturing efficiency and oil displacement efficiency, and providing new technical support for the sustainable development of the energy industry. This study innovatively designed an amphiphilic modified amino silicone oil polymer (MA-co-MPEGA-AS) by combining maleic anhydride (MA), methoxy polyethylene glycol acrylate (MPEGA), and amino silicone oil (AS) through a molecular bridge strategy. The synthesis process involved three key steps: radical polymerization of MA and MPEGA, amidation with AS, and in situ network formation. Fourier transform infrared spectroscopy (FT-IR) confirmed the successful introduction of ether-based CO₂-philic groups. Rheological tests conducted under scCO₂ conditions demonstrated a 114-fold increase in viscosity for MA-co-MPEGA-AS. Mechanistic studies revealed that the ether oxygen atoms (Lewis base) in MPEGA formed dipole–quadrupole interactions with CO₂ (Lewis acid), enhancing solubility by 47%. Simultaneously, the self-assembly of siloxane chains into a three-dimensional network suppressed interlayer sliding in scCO₂ and maintained over 90% viscosity retention at 80 °C. This fluorine-free design eliminates the need for platinum-based catalysts and reduces production costs compared to fluorinated polymers. The hierarchical interactions (coordination bonds and hydrogen bonds) within the system provide a novel synthetic paradigm for scCO₂ thickeners. This research lays the foundation for green CO₂-based energy extraction technologies. Full article

There are many advantages of the smelting of vanadium–titanium magnetite pellets by hydrogen-based shaft furnace pre-reduction and electric arc furnace process, including high reduction efficiency, low carbon dioxide emission and high recovery of titanium and so on. However, vanadium–titanium magnetite pellets are highly susceptible to severe reduction disintegration when reduced in the gas-based shaft furnaces. H₂ and CO are the primary reducing gas components in the gas-based shaft furnace process, which significantly influences the reduction behavior of vanadium–titanium magnetite pellets. In this study, the reduction disintegration behavior and reduction kinetics of vanadium–titanium magnetite under mixed H₂–CO atmospheres at low temperatures (450–600 °C) were investigated. The differences in the reduction capacities and rates of H₂ and CO on iron oxides and titanium–iron oxides were revealed, along with their impact on the reduction disintegration behavior of the pellets at low temperatures. At lower temperatures, CO exhibited a greater reducing capability for vanadium–titanium magnetite. As the reduction temperature increased, the reduction capacities of both H₂ and CO improved; however, the reduction capacity of H₂ was more significantly influenced by the temperature. The disparity in the reduction capacities of H₂ and CO for vanadium–titanium magnetite pellets caused an inconsistent expansion rate in different regions of the pellet, increasing internal stress, contributing to a more severe reduction disintegration of vanadium–titanium magnetite pellets in the mixed H₂–CO atmospheres. Full article

Using hydrogen peroxide (H₂O₂), a simple and easily accessible reagent, as a selective depressant, flotation separation experiments of chalcopyrite and copper-activated sphalerite were conducted. The micro-flotation tests of single minerals indicated that H₂O₂ selectively depresses copper-activated sphalerite and exerted almost no depressant effect on chalcopyrite. In the flotation tests of artificially mixed minerals, a copper concentrate with a grade of 29.95% and a recovery of 87.30% was obtained, while the zinc content was only 5.76%, demonstrating a significant separation effect. The results of contact angle measurement, Zeta potential measurement, surface adsorption analysis, and XPS analysis suggested that H₂O₂ had a stronger oxidation capacity on the surface of copper-activated sphalerite than chalcopyrite, generating hydrophilic hydroxyl groups on the surface of sphalerite and preventing further adsorption of the collector Z-200 on the surface of sphalerite. Full article

Salmonella is a rapidly spreading and widespread zoonotic infectious disease that poses a serious threat to the safety of both poultry and human lives. Therefore, the timely detection of Salmonella in foods and animals has become an urgent need for food safety. This work describes the construction of an aptamer-based sensor for Salmonella detection, using Fe₃O₄ magnetic beads and Ag@Au core–shell nanoparticles-embedded 4-mercaptobenzoic acid (4MBA). Leveraging the high affinity between biotin and streptavidin, aptamers were conjugated to Fe₃O₄ magnetic beads. These beads were then combined with Ag@4MBA@Au nanoparticles functionalized with complementary aptamers through hydrogen bonding and π-π stacking interactions, yielding a SERS-based aptamer sensor with optimized Raman signals from 4MBA. When target bacteria are present, aptamer-conjugated magnetic beads exhibit preferential binding to the bacteria, leading to a decrease in the surface-enhanced Raman scattering (SERS) signal. And it was used for the detection of five different serotypes of Salmonella, respectively, and the results showed that the aptamer sensor exhibited a good linear relationship between the concentration range of 10²–10⁸ CFU/mL and LOD is 35.51 CFU/mL. The SERS aptasensor was utilized for the detection of spiked authentic samples with recoveries between 94.0 and 100.4%, which proved the usability of the method and helped to achieve food safety detection. Full article

The development of alternative energy is crucial to realizing the goals of the Paris Agreement. Hydrogen is a key energy carrier, and ammonia is considered its practical storage medium due to its high H₂ content and efficient storage and transportation. However, efficient NH₃ decomposition methods are needed to recover stored hydrogen. Plasma-assisted decomposition offers a potential solution, but high energy consumption, mainly due to inefficient power supply systems, remains a challenge. This study examines the impact of varying the driving frequency of a gliding discharge plasma system on ammonia decomposition, comparing low-frequency 50 Hz and high-frequency 20 kHz power supplies. Results show that high-frequency plasma enhances electron density and energy distribution, increasing the amount of vibrationally excited nitrogen molecules. This improves catalyst activation, leading to higher ammonia conversion and hydrogen production. Compared to the thyristor-powered system, the high-frequency system increased ammonia decomposition productivity by 30% and reduced energy consumption by 36% using a coprecipitated catalyst. These findings emphasize the importance of a plasma generator optimizing plasma-assisted ammonia decomposition and improving efficiency in hydrogen production. Full article

In this study, a methacrylic derivative of xylan (XYLMA) was synthesized through transesterification reactions, with the aim of evaluating its physicochemical behavior and its interaction with kaolinite particles. Structural characterization by FT-IR and NMR spectroscopy confirmed the incorporation of methacrylic groups into the xylan (XYL) structure, with a degree of substitution of 0.67. Thermal analyses (TGA and DSC) showed a decrease in melting temperature and enthalpy in XYLMA compared to XYL, attributed to a loss of structural rigidity. Thermal analyses (TGA and DSC) revealed a decrease in the melting temperature and enthalpy of XYLMA compared to XYL, which is attributed to a loss of structural rigidity and a reduction in the crystalline order of the biopolymer. Aggregation tests in solution revealed that XYLMA exhibits amphiphilic behavior, forming micellar structures at a critical aggregation concentration (CAC) of 62 mg L⁻¹. In adsorption studies on kaolinite, XYL showed greater affinity than XYLMA, especially at acidic pH, due to reduced electrostatic forces and a greater number of hydroxyl groups capable of forming hydrogen bonds with the mineral surface. In contrast, modification with methacrylic groups in XYLMA reduced its adsorption capacity, probably due to the formation of supramolecular aggregates. These results suggest that interactions between xylan and kaolinite clay are key to understanding the role that hemicelluloses play in increasing copper recovery when added to flotation cells during the processing of copper sulfide ores with high clay content. Full article

CO₂-biomethanation was studied in the present manuscript by considering the direct injection of hydrogen into a conventional anaerobic digester treating sewage sludge within a simulated wastewater treatment plant (WWTP). The plant was simulated using the Python 3.12.4 software, and a Monte Carlo simulation was conducted to account for the high variability in the organic content of the wastewater and the methane potential of the sludge. Two modes of operation were studied. The first mode involves the use of an anaerobic digester to upgrade biogas, and the second mode considers using the digester as a CO₂ utilization unit, transforming captured CO₂. Upgrading biogas and utilizing the extra methane to generate electricity within the same plant leads to a negative economic balance (first scenario). A hydrogen injection of 1 L of H₂/L_r d (volumetric H₂ injection per liter of reactor per day) was required to transform the CO₂ present in the biogas into methane. The benefits associated with this approach resulted in lower savings regarding heat recovery from the electrolyzer, increased electricity production, and an additional oxygen supply for the waste-activated sludge treatment system. Increasing the injection rate to values of 5 and 30 L of H₂/L_r d was also studied by considering the operation of the digester under thermophilic conditions. The latter assumptions benefited from the better economy of scale associated with larger installations. They allowed for enough savings to be obtained in terms of the fuel demand for sludge drying, in addition to the previous categories analyzed in the biogas upgrading case. However, the current electricity price makes the proposal unfeasible unless a lower price is set for hydrogen generation. A standard electricity price of 7.6 c€/kWh was assumed for the analysis, but the specific operation of producing hydrogen required a price below 3.0 c€/kWh to achieve profitability. Full article

The robust structure of algal cell walls presents a major barrier in the recovery of fermentable sugars and intracellular lipids for biofuel production. This study investigates the effectiveness of ultraviolet (UV) radiation and UV-assisted hydrogen peroxide (UV/H₂O₂) pretreatment on a local mixed marine algal culture to enhance biofuel production through cell wall disruption. Local mixed cultures of marine microalgae (LMCMA) were pretreated with UV for various exposure times (5–30 min) and with UV/H₂O₂ using H₂O₂ concentrations ranging from 0.88 to 3.53 mM. The impact of pretreatment was evaluated based on morphological changes (SEM and TEM), elemental composition (C, H, N), sugar release, and downstream fermentation yields of ethanol, methanol, 1-propanol, 1-butanol, and 1-pentanol using Saccharomyces cerevisiae. UV pretreatment at 20–30 min yielded the highest carbohydrate release (up to 0.025 g/gDCW), while UV/H₂O₂ at 1.76 mM achieved maximum sugar liberation (0.0411 g/gDCW). Fermentation performance was enhanced under optimized conditions, with peak ethanol yields of 0.3668 g ethanol/g carbohydrates (UV, 30 min, 48 h) and 0.251 g ethanol/g (UV/H₂O₂, 0.88 mM, 24 h). This study also demonstrated selective production of higher alcohols under varying fermentation temperatures (30–37 °C). These findings highlight the potential of combining oxidative pretreatment and process optimization to enhance biofuel recovery from environmentally relevant algal biomass. Full article