Optimum Preparation Conditions Research Articles

Separation of heavy metals from dilute solutions using D2EHPA carrier fixed onto the outer surface of coaxially electrospun core-sheath fibers

In this study, porous membranes based on core-sheath fibers covered with fixed carriers were prepared by coaxial electrospinning for the separation of heavy metal ions from dilute solutions. Cellulose triacetate (CTA) and an extractant di(2-ethylhexyl)phosphoric acid (D2EHPA) were mixed to prepare a sheath-layer solution and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was adopted to prepare a core-layer solution for electrospinning. The morphological and textural properties as well as chemical composition of the fabricated core-sheath fibers were first analyzed to determine the optimal preparation conditions. The ability and selectivity of such fixed D2EHPA carriers were evaluated via the adsorption of Zn2+, Cu2+, and Ni2+ ions from dilute solutions. Dynamic tests revealed that the adsorption of metal ions on the core-sheath fibrous membrane made of 52 wt% PVDF-HFP, 18 wt% D2EHPA, and 30 wt% CTA (on a dry basis) reached equilibrium within 8 h. As expected, all adsorption isotherms at specific equilibrium pH values were well described by the Langmuir equation, ascribed to the chemical reaction nature between metal ions and D2EHPA carrier. The crossflow permeation-adsorption tests of a multi-metal solution in a total recycling mode revealed the adsorption selectivity of Zn2+ over Cu2+ and Ni2+, as observed in conventional liquid–liquid extraction. Four repeated adsorption-regeneration experiments revealed an adsorption efficiency beyond 95 % relative to the first route, demonstrating the satisfactory reusability and stability of the as-prepared core-sheath fibrous membranes for this purpose.

Tribological Performance Study of Low-Friction PEEK Composites under Different Lubrication Conditions

This study introduces a low-friction composite based on PEEK to improve its friction and wear properties. The composite incorporates PTFE as a solid lubricant and utilizes PPTA as a reinforcing material within the PEEK matrix. These components were prepared utilizing a compression molding method, followed by a series of exploratory experiments to identify the optimal preparation conditions for PEEK. This research assesses how the PTFE/PPTA/PEEK composites perform in terms of friction and wear under dry and oil-lubricated conditions. By examining wear tracks using scanning electron microscopy and white light interference microscopy, this study aims to uncover the wear mechanisms of PEEK and its composites under different lubrication scenarios. Results show that the main wear mechanisms for the PTFE/PPTA/PEEK composites and bearing steel are ploughing and adhesive wear. The presence of PPTA helps reduce wear by leveraging its strong fibers and thermal stability, while the coefficient of friction decreases as PTFE creates a smooth, solid lubricating film on the surface. Notably, PEEK composites containing 25 wt% PTFE and 6 wt% PPTA demonstrate the lowest wear rates and reduced coefficient of friction in both dry and oil-lubricated conditions.

Green Preparation and Antibacterial Activity Evaluation of AgNPs-Blumea balsamifera Oil Nanoemulsion.

Bacterial infection is a thorny problem, and it is of great significance to developing green and efficient biological antibacterial agents that can replace antibiotics. This study aimed to rapidly prepare a new type of green antibacterial nanoemulsion containing silver nanoparticles in one step by using Blumea balsamifera oil (BBO) as an oil phase and tea saponin (TS) as a natural emulsifier and reducing agent. The optimum preparation conditions of the AgNPs@BBO-TS NE were determined, as well as its physicochemical properties and antibacterial activity in vitro being investigated. The results showed that the average particle size of the AgNPs@BBO-TS NE was 249.47 ± 6.23 nm, the PDI was 0.239 ± 0.003, and the zeta potential was -35.82 ± 4.26 mV. The produced AgNPs@BBO-TS NE showed good stability after centrifugation and 30-day storage. Moreover, the AgNPs@BBO-TS NE had an excellent antimicrobial effect on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. These results demonstrated that the AgNPs@BBO-TS NE produced in this study can be used as an efficient and green antibacterial agent in the biomedical field.

Targeted preparation of six rare ginsenosides using two β-glucosidases from Bifidobacterium adolescentis

In this study, six rare protopanaxadiol (PPD)-type ginsenosides, namely, F2, CK, C-Mc1, C-Mc, CO, and CY, were prepared using enzymatic hydrolysis. Firstly, major (PPD)-type ginsenosides, including Rb1, Rb2, Rc, and Rd, were biotransformed by employing single and combined β-glucosidases BaBgl1A and BaBgl3A. Thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) analyses revealed that ginsenosides F2, CO, and C-Mc1 could be produced by BaBgl1A, while rare ginsenosides CK, CY, and C-Mc could be produced by the combined use of BaBgl1A and BaBgl3A. Furthermore, optimal preparation conditions for these rare ginsenosides were elucidated, with yields exceeding 76.34%. Additionally, large quantities of rare ginsenosides were prepared to determine their structures. Characteristic absorption peaks in 13C NMR spectra and ion peaks in MALDI-TOF-MS suggested that the six high-purity rare ginsenosides (i.e., F2, CO and C-Mc1, CK, CY, and C-Mc) could be produced at high-efficiency. The findings of this study offer insights into novel enzymolysis methods for the targeted preparation of rare PPD-type ginsenosides, thus widening the range of raw materials that could be directed to in-depth biological activity research.

Investigating the Influence of Processing Conditions on Dissolution and Physical Stability of Solid Dispersions with Fenofibrate and Mesoporous Silica.

The study aimed to enhance the solubility of the poorly water-soluble drug, fenofibrate, by loading it onto mesoporous silica, forming amorphous solid dispersions. Solid dispersions with 30% fenofibrate were prepared using the solvent evaporation method with three solvents (ethyl acetate, acetone, and isopropanol) at different temperatures (40 °C, boiling point temperature). Various characteristics, including solid-state properties, particle morphology, and drug release, were evaluated by different methods and compared to a pure drug and a physical mixture of fenofibrate and silica. Results revealed that higher solvent temperatures facilitated complete amorphization and rapid drug release, with solvent choice having a lesser impact. The optimal conditions for preparation were identified as ethyl acetate at boiling point temperature. Solid dispersions with different fenofibrate amounts (20%, 25%, 35%) were prepared under these conditions. All formulations were fully amorphous, and their dissolution profiles were comparable to the formulation with 30% fenofibrate. Stability assessments after 8 weeks at 40 °C and 75% relative humidity indicated that formulations prepared with ethyl acetate and at 40 °C were physically stable. Interestingly, some formulations showed improved dissolution profiles compared to initial tests. In conclusion, mesoporous silica-based solid dispersions effectively improved fenofibrate dissolution and demonstrated good physical stability if prepared under appropriate conditions.

Engineering 2D nano-sheet struvite by ethanol regulation for boosting flame retardant properties

Struvite exhibits versatile applications as both a slow-release fertilizer and an inorganic flame-retardant material. In this study, we present a successful synthesis method for producing nano-sheet struvite with a remarkably thin nanoscale thickness of 63 nm and an impressive specific surface area of 128.4 m2·g−1. Our approach involves a combination of ethanol supplementation and ammonia diffusion. By employing MgCl2·6H2O and NaH2PO4·2H2O as reactants, with a Mg2+:PO43- molar ratio of 1:2, and incorporating 50 vol% ethanol, we achieved optimal preparation conditions. Moreover, we determined that a reaction time of 20 min and a reaction pH ranging from 9.3 to 9.5 yielded the best results. The experimental results revealed that the nano-sheet variant of struvite exhibited exceptional physical barrier properties achieving a flame retardance rate of 92.6 %, surpassing other morphologies such as rod-like, butterfly-like, and needle-like variants. And the optimal usage amount of nano-sheet struvite on the wood surface was determined to be 8.5 × 10−3 g·cm−2. Furthermore, the mechanism of the ethanol solvent in the formation process of 2D nano-sheet struvite was preliminarily discussed, offering a viable approach for the preparation of struvite with high flame retardant performance.

Study on Preparation and Humidity-Control Capabilities of Vermiculite/Poly(sodium Acrylate-acrylamide) Humidity Controlling Composite.

This paper focuses on the preparation and evaluation of a novel humidity-control material, vermiculite/(sodium polyacrylate(AA)-acrylamide(AM)), using inverse suspension polymerization. Acrylic acid and acrylamide were introduced into the interlayer of modified vermiculite during the polymerization process, leading to the formation of a strong association with the modified vermiculite. The addition of vermiculite increased the specific surface area and pore volume of the composites. To investigate the moisture absorption and desorption properties of the composites, an orthogonal experiment and single-factor experiment were conducted to analyze the impacts of vermiculite content, neutralization degree, and the mass ratio of AA to AM. According to the control experiment, the addition of vermiculite was found to enhance the pore structure and surface morphology of the composite material, surpassing both vermiculite and PAA-AM copolymer in terms of humidity control capacity and rate. The optimal preparation conditions were identified as follows: vermiculite mass fraction of 4 wt%, a neutralization degree of 90%, and mAA:mAM = 4:1. The moisture absorption rate and moisture release rate of the composite material prepared under these conditions are 1.285 g/g and 1.172 g/g. The humidity control process of the composite material is governed by pseudo second-order kinetics, which encompasses the complete adsorption process. These results indicate that the vermiculite/PAA-AM composite humidity control material has excellent humidity control performance and is a simple and efficient humidity control method.

Process optimization of Cd2+ removal with Tetradesmus Obliquus-immobilized Algal Beads

In this study, calcium alginate-immobilized microalgae beads were utilized for treating Cd2+-containing wastewater by optimizing the algal species, the preparation conditions of immobilized beads, and the Cd2+ treatment conditions to enhance treatment efficiency. The results revealed that under optimal preparation conditions with a CaCl2 concentration of 3 % and a sodium alginate concentration of 2 %, the removal rate of Cd2+ reached 94.99 % after 3 h of adsorption when 4 g of immobilized Tetradesmus obliquus algal beads were added to a 20 mg/L Cd2+ solution. Additionally, under optimal removal conditions at pH=6, with immobilized Tetradesmus obliquus algal beads as the adsorbent and a dosage of 6 g of immobilized algal beads added to a solution with an initial Cd2+ concentration of 15 mg/L, the Cd2+ removal rate reached 99.85 % after 4 h of adsorption, surpassing that of suspended microalgae and blank algal beads. The adsorption process followed the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. FTIR analysis indicated that functional groups such as O-H, CO, C-O, C-N, among others, might play a role in the adsorption process. After five adsorption-desorption cycles, the adsorption capacity decreased by only 10 %. This study demonstrated that immobilized Tetradesmus obliquus algal beads is an efficient and renewable and recyclable adsorbent.

Degradation of phenol by Cu-Ni bimetallic-doped sludge biochar as a fenton-like catalyst: Mechanistic study and practical application

In this study, the sewage sludge was converted into sludge biochar (SBC) and doped with Cu-Ni bimetal to synthesize a novel composite catalyst (Cu-Ni@SBC) for the activation of H2O2 for phenol degradation. Characterization results showed that the Cu-Ni bimetal was successfully doped into the SBC and led to the formation of a porous structure with abundant cavities, resulting in a larger specific surface area and higher adsorbed oxygen content. Mechanism analysis revealed a valence state conversion cycle between Cu0-Cu(II), Ni(III)-Ni(II) and Cu-Ni which made Cu-Ni@SBC have higher electron transfer performance. Response surface methodology was applied to determine the optimal preparation and reaction conditions, under which the Fenton-like system composed of Cu-Ni@SBC and H2O2 removed 100 % of phenol and mineralized 69.1 % of TOC from simulated wastewater. In addition, the experimental results showed that the Cu-Ni@SBC material had a relatively wide pH adaptation range (4–8), and the removal efficiency of phenol could reach 76.4 % after 5 cycles of experiments, and the catalytic inhibition rates of the two common coexisting anions, HCO3– and Cl-, were 17.1 % and 0 %, respectively. The results of practical application revealed that the phenol removal efficiency reached 90.44 % and the pollutant mineralization rate could reach 58.5 % within 90 min, which proved that the catalyst was suitable for the advanced degradation of organic matter in coal chemical wastewater. Therefore, Cu-Ni@SBC can be considered as a promising Fenton-like catalyst, and the process method is also of some guiding significance for the treatment of coal chemical wastewater.

Enhancing H2O2 production with a self-breathing gas diffusion electrode fabricated via ultrasonic impregnation and vacuum filtration

In this study, an electro-Fenton gas diffusion electrode featuring air self-respiration was fabricated by incorporating carbon nanotubes, carbon nitride, and polytetrafluoroethylene onto graphite felt. The fabrication process involved a synergistic approach of ultrasonic impregnation and vacuum filtration, establishing a gas–liquid-solid tri-phase interface both on the surface and within the electrode. This preparation method facilitates autonomous air intake, diffusing it to the tri-phase reaction interface, thereby eliminating the necessity for aeration and reducing operational costs. The optimal electrode preparation conditions were determined through Box-Behnken Design response surface experiments, leading to the enhancement of H2O2 production conditions. Under the optimized conditions, H2O2 accumulation reached 45.83 mg L−1 cm−2h−1, surpassing the performance achieved with conventional ultrasonic impregnation and vacuum filtration methods. Furthermore, the performance of self-breathing and the impact factors are explored. Finally, the electrode’s efficacy was demonstrated through the degradation of phenol and bisphenol A with concentrations of 100 mg L−1 exhibiting degradation rates of 92 % and 95 %, respectively, within 60 min.

Application of iron-manganese oxide fillers in bioretention facility: Enhanced removal of antibiotics and conventional contaminants

Bioretention facilities are common source reduction facilities, but traditional fillers are not effective in reducing emerging contaminants such as antibiotics. Although Fe-Mn oxides have been extensively explored, their removal of emerging contaminants and application in the sponge city have not yet been addressed. Therefore, this study aims to address this limitation by developing Fe-Mn oxide fillers. In this research, the optimal preparation conditions (Fe/Mn mole ratio, polyvinyl alcohol (PVA) concentration, and filler particle size) and influencing factors (filler dosage, initial pollutant concentration, pH, temperature, and co-existing ions) were investigated using a typical antibiotic, norfloxacin (NOR), as the target contaminant. The removal mechanism of NOR was investigated by SEM, FTIR, and XPS characterizations. Subsequently, the fillers were applied to bioretention facilities with different filling modes (layered and mixed) to evaluate their effectiveness in removing NOR and conventional pollutants at different recurrence periods, drought periods, and pollutant influent concentrations. The study indicated that Fe-Mn oxide filler (Fe/Mn mole ratio of 4:1, PVA concentration of 7 %, particle size of 4 mm) could remove more than 70 % of NOR (1–20 mg/L). The NOR removal by Fe-Mn oxide filler involved adsorption and redox reactions. Notably, bioretention facilities using Fe-Mn oxide fillers have shown varying degrees of improvement in the removal of NOR and conventional pollutants compared to conventional ones. This study contributes to the application of Fe-Mn oxide filler in bioretention facilities, thus playing a crucial role in mitigating antibiotic pollution in stormwater runoff.

Construction of a food waste biochar model and determination of contaminant adsorption sites: Combining experimental characterisation with quantum chemical calculations

Increasing urbanization has made it a serious challenge to deal with food waste (FW) from people and wastewater with pollutants from industry. Biochar from FW pyrolysis(FWB) can be used as an adsorbent to adsorb pollutants from wastewater, but its molecular structure is still unknown, limiting the understanding of its adsorption mechanism and its application in industry. In this paper, a series of combined methods of experimental characterization and quantum chemical calculations, such as solid-state 13C nuclear magnetic resonance spectroscopy (13C NMR), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to investigate and successfully construct a model of the molecular structural features of FWB under the optimal contaminant adsorption preparation conditions. Based on the electrostatic potential distribution and adsorption experiments, the adsorption sites of the pollutants were elucidated. The results showed that the FWB prepared at different temperatures, 450 °C had a variety of oxygen-containing functional groups and polarity favorable for adsorption. In the molecular structure of FWB with the molecular formula C60H49N7O8, oxygen is present in the form of carboxyl, carbonyl, ether, alcohol hydroxyl, and phenol hydroxyl groups with numbers 1, 1, 1, 1, 2, 1, 2. Nitrogen is present in the form of pyridinyl nitrogen, pyrrolidinyl nitrogen, and primary amines with numbers 1, 1, and 5, respectively. In addition, nitrogen-containing and oxygen-containing functional groups are possible adsorption sites for pollutants on FWB, and alcohol hydroxyl and amino groups can bind better to Cu2+, which provides scientific guidance for improving the adsorption performance of biochar. This provides a solid foundation for the study of the microscopic adsorption mechanism of FWB and a method for the modeling of biochar from other biomasses.

Glycated Walnut Meal Peptide-Calcium Chelates: Preparation, Characterization, and Stability.

Finding stable and bioavailable calcium supplements is crucial for addressing calcium deficiency. In this study, glycated peptide-calcium chelates (WMPHs-COS-Ca) were prepared from walnut meal protein hydrolysates (WMPHs) and chitosan oligosaccharides (COSs) through the Maillard reaction, and the structural properties and stability of the WMPHs-COS-Ca were characterized. The results showed that WMPHs and COSs exhibited high binding affinities, with a glycation degree of 64.82%. After glycation, Asp, Lys, and Arg decreased by 2.07%, 0.46%, and 1.06%, respectively, which indicated that these three amino acids are involved in the Maillard reaction. In addition, compared with the WMPHs, the emulsifying ability and emulsion stability of the WMPHs-COS increased by 10.16 mg2/g and 52.73 min, respectively, suggesting that WMPHs-COS have better processing characteristics. After chelation with calcium ions, the calcium chelation rate of peptides with molecular weights less than 1 kDa was the highest (64.88%), and the optimized preparation conditions were 5:1 w/w for WMPH-COS/CaCl2s, with a temperature of 50 °C, a chelation time of 50 min, and a pH of 7.0. Scanning electron microscopy showed that the "bridging role" of WMPHs-COS changed to a loose structure. UV-vis spectroscopy and Fourier transform infrared spectrometry results indicated that the amino nitrogen atoms, carboxyl oxygen atoms, and carbon oxygen atoms in WMPHs-COS chelated with calcium ions, forming WMPHs-COS-Ca. Moreover, WMPHs-COS-Ca was relatively stable at high temperatures and under acidic and alkaline environmental and digestion conditions in the gastrointestinal tract, indicating that WMPHs-COS-Ca have a greater degree of bioavailability.

Preparation of CaO@CeO2 Solid Base Catalysts Used for Biodiesel Production

The study investigated the use of CeO2 extracted from monazite with calcium oxide (CaO) as a solid catalyst for biodiesel production. The wet impregnation method was used to produce CaO@CeO2 mixed-oxide catalysts with 0–50 wt.% CaO. X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, thermogravimetric analysis (TGA), and a Fourier transform infrared spectrometer (FTIR) was used to characterize the catalysts. In order to determine the optimal preparation conditions, the effect of different CaO compositions on the performance of CaO@CeO2 mixed-oxide catalysts was examined. The catalytic activity of the CaO@CeO2 catalyst for the transesterification reaction of palm oil to produce biodiesel was studied. The results show that the optimum yield of biodiesel can reach 97% fatty acid methyl ester over the 30CaO@CeO2 catalyst at the reaction conditions of 5 wt.% catalysts, methanol-to-oil molar ratio of 9:1, with a reaction temperature of 65 °C within 30 min. The results show that the high catalytic activity and stability of the CaO@CeO2 catalyst make it a promising candidate for industrial-scale biodiesel production. Further study is needed to improve the stability and efficiency of catalysts in transesterification reactions to achieve a high FAME yield using long-life-span catalysts. Moreover, it is necessary to investigate the economic feasibility of this process for application in large-scale biodiesel production.

Modification of polyvinyl alcohol with 2-hydroxypropionic acid and cross-linking with glutaraldehyde for the preparation of biodegradable mulch paper and its properties

Abstract The preparation of biodegradable mulch film with paper-based materials has become a significant focus in mulch film development due to the serious pollution caused by plastic mulch film. This study utilized the esterification cross-linking reaction of LA, PVA, and GA to coat the surface of paper as the substrate. FTIR, TGA, XRD, SEM, tensile testing, and oxygen, water vapor barrier performance tests were performed. The optimal conditions for film preparation were determined to be a 10 % PVA aqueous solution, 5 % GA content, and a PVA/LA/GA ratio of 1:2:1. The resulting film paper exhibited a dry strength of 6.52 kN/m, a wet strength of 0.23 kN/m, a tearing degree of 969.35 mN, a Cobb value of 12.04 g/m2, a water vapor transmission rate of 573.27 g m−2 24 h−1, and an oxygen transmission rate of 7.373 cm3 m−2 24 h−1. After a 6-week landfill degradation test, the film showed a degradation rate of 25.3 %, while still maintaining a tensile strength of 1.89 kN/m. Field application tests in greenhouses confirmed that the film paper facilitated the growth of strawberry, its mechanical and barrier properties suitable for a biodegradable paper mulch.

Effects of Sheep Bone Peptide-Chelated Calcium on Calcium Absorption and Bone Deposition in Rats Fed a Low-Calcium Diet

Sheep bones, as the main byproduct after sheep slaughter, are rich in proteins, but their utilization in deep processing is relatively low. Currently, calcium deficiency is a common health issue that can lead to metabolic bone diseases. Peptide calcium chelate is considered a superior substance, having a significant effect on improving the absorption and utilization efficiency of calcium in the human body. This study used sheep bone byproducts as the raw material to prepare sheep bone peptide-chelated calcium (SBP-Ca) and its structure was characterized and analyzed in depth. SBP-Ca was supplemented in a low-calcium diet to assess its effects on calcium absorption and bone formation in a rat model experiencing calcium deficiency. The results showed that under optimal preparation conditions for SBP-Ca (peptide-calcium ratio set at 1 : 1, pH maintained at 7, temperature set to 45°C, and duration of 60 min), calcium could chelate with sheep bone peptide (SBP) at the sites C=O, -NH2, and -COOH sites, forming a structurally dense SBP-Ca with a chelation rate of up to 89.24%. In rats fed a low-calcium diet, SBP-Ca significantly improved the rat femoral diameter, dry weight, trabecular bone structure, bone density, and bone volume fraction (P<0.05). A decline in serum alkaline phosphatase levels (P<0.05), elevation in bone calcium content, and a rise in serum osteocalcin levels (P<0.05) were observed. Furthermore, morphological studies on bone tissue suggest that SBP-Ca has the ability to restore trabecular bone structure. In conclusion, SBP-Ca has been successfully prepared as a novel calcium absorption promoter. By improving the bioavailability of calcium, bone formation was facilitated, demonstrating a significant application value in the prevention of calcium deficiency disorders.

Optimizing preparation of low-NaCl protein gels from goose meat and understanding synergistic effects of pH/NaCl in improving gel characteristics

This study explored the feasibility of partially substituting NaCl with MgCl2 in preparing gel products from goose meat. Furthermore, the effects of synergistic interaction between different pH levels and NaCl concentrations on the structure and characteristics of the gels were explored by analyzing their secondary structure, microstructure, and water-distribution properties. The results showed that NaCl could be partially substituted by MgCl2, with the optimal preparation conditions: NaCl (0.83 mol/L), pH (7.3), MgCl2 (0.04 mol/L), heating temperature (79 °C), heating time (20 min), and solid-liquid ratio (1:3). Furthermore, the pH had a more significant impact on the gels' structure and characteristics than did NaCl concentration. Thus, our optimized method can reduce the usage of NaCl in the gel products while at the same time improving the characteristics of gel products under low-NaCl conditions by lowering pH, laying a solid theoretical foundation for producing low-NaCl protein gel products from goose meat.

Modification of red mud catalyst using oxalic acid-assisted UV treatment for toluene removal

An innovative simplified modification method for red mud had been proposed, which enabled its utilization as an active Fe2O3-rich component for catalytic oxidation of toluene. The Box-Behnken design, based on Response Surface Methodology (RSM), was employed to optimize the modification of bauxite residue using oxalic acid combined with UV irradiation. Based on the experimental conditions, the optimal conditions for three independent parameters were determined: acid leaching time (2 hours), UV irradiation time (1 hour), and acid dosage (150 ml),which was in order to enhance the maximum catalytic efficiency of toluene at 300 °C. Under the optimal preparation conditions provided by the Box-Behnken design, the catalytic efficiency of toluene at 300°C could reach 99.2%. In comparison to the acid-modified mud (MRM) and untreated bauxite residue (RM), the aluminum refinery residue modified with oxalic acid-assisted UV irradiation (MRM-UV) exhibited the formation of oxalate sub-iron precipitates, resulting in significantly lower catalytic temperatures (238°C). Furthermore, through XRF, XRD, XPS, O2-TPD, and H2-TPD analysis, it was discovered that a large amount of iron oxide and calcium oxide formed CaO+Fe2O3→Ca2Fe2O5, strengthening the interaction between iron and calcium, augmenting the migration rate of lattice oxygen from the bulk phase to the surface. Consequently, T50 were reduced by 20.9% and 31.8% when compared to MRM and RM. Moreover, the CO2 selectivity of MRM-UV increased from 8.6% to 70.5% compared to RM at 300°C. Using in situ DRIFTS, the reaction pathway of toluene on MRM-UV was identified as benzyl alcohol → benzaldehyde or benzoyl → benzoate→maleic anhydride→CO2 and H2O. The process refinement reduced VOCs emissions and promoted sustainable waste management by combining oxalic acid with catalytically active red mud.

Reduction of oxygen vacancies in Mg–N codoped Ga2O3 films for improving solar-blind UV photodetectors performance

Solar-blind photodetectors based on gallium oxide (Ga2O3) have shown possibilities in optical imaging, spatial communication, and other fields. The high oxygen vacancy (VO) content inherent in Ga2O3 film would inevitably result in poor photoelectric detection capability. This work suggests using a codoping for reducing VO concentrations in Ga2O3 films. In a N2O atmosphere, magnesium and nitrogen codoped gallium oxide (Mg–N:Ga2O3) films were grown using the pulsed laser deposition (PLD) technique on (0001) sapphire substrates. It is possible to produce codoped Ga2O3 thin films with low oxygen vacancy density and high crystalline quality by thoroughly examining and optimizing preparation conditions. Metal-semiconductor-metal (MSM) photodetectors were constructed using both pristine and Mg–N codoped Ga2O3 thin films as the active layer. The photodetector with a codoped active layer outperforms those with pristine Ga2O3, with a quick decay time of 20 ms, a high sensitivity of 2.61 × 105, and a high responsivity of 0.191 A/W under 254 nm UV light irradiation, highlighting the significance of the VO concentration decrease in the application of Ga2O3-based solar-blind photodetectors.

Low over-potential cathode synthesized using a binary metal self-templated molybdenum reinforced method for highly efficient hydrogen evolution

To solve the problem of renewable energy generation fluctuation, water splitting for hydrogen generation is proposed, which can store renewable energy as hydrogen energy. Low overpotential cathode materials can effectively reduce the cost of hydrogen production. Here, a new NiMo/NMF electrode was prepared using a hydrothermal coupled H2 reduction method. Three-dimensional NiMo nanorod arrays were constructed by modulating the ion dissolution and surface epitaxial growth process of the electrode substrate. The influence of different hydrothermal reaction and H2 reduction conditions on the electrochemical performance of the electrode was investigated. Under optimum preparation conditions, the NiMo/NMF electrode exhibits a extremely low overpotentials of 158 mV at 500 mA cm-2 (30% wt. KOH alkaline medium), which can serve for preparing high efficiency and economy electrodes by in-situ integration of high active components on metal foam substrate. The NiMo/NMF electrode is a high-performance electrocatalytic cathode material with great prospects for industrial applications.