Degradation of trichloroacetic acid by Fe/Ni bimetallic reactive PMS with hierarchical layered structure.

Overuse of chlorinated disinfectants leads to a significant accumulation of disinfection by-products. Trichloroacetic acid (TCA) is a typical carcinogenic disinfection by-product. The efficacy of the conventional degradation process is reduced by the complex nature of its structure, causing a yearly increase in its prevalence within the ecological environment and consequent infliction of significant harm. In this paper, TCA was chosen as the research subject, Fe/Ni bimetallic nanoparticles were employed as the reducing catalyst, ZIF-8@HMON as the catalytic carrier combined with Fe/Ni nanoparticles, and peroxymonosulfate (PMS) was introduced to construct the reducing-advanced oxidation synergistic system and investigated the effect of this system on the degradation performance and degradation pathway of TCA. Various characterization techniques, including TEM, SEM, XRD, FT-IR, XPS, BET, were employed to investigate the morphology, element composition and structure of composite materials analysis. Moreover, the conditions for TCA degradation can be optimized by changing the experimental environment. The results showed that 25 mg of composite catalyst (mole ratio Fe: Ni = 1:1) and 10 mg of PMS effectively degraded TCA within 20-80 mg/L range at pH = 3 and 55 °C, achieving maximum degradation within 20 min. Finally, the potential pathways of TCA degradation were analyzed using EPR and LC-MS, and the corresponding reaction mechanisms were proposed.

Study on free and entangled binary metal nanocatalysts for removal of 2,4,6-trichlorophenol in aqueous phase: a comparative study.

The present study highlights the comparative catalytic removal of 2,4,6-trichlorophenol (TCP) in the aqueous phase by binary nanoparticles in free as well as entangled forms. In brief, binary nanoparticles comprising Fe-Ni are prepared, characterized, and subsequently entangled in reduced graphene oxide (rGO) for better performances. Optimization studies on the mass of free and rGO-entangled binary nanoparticles with respect to TCP concentration and other environmental factors were carried out. Results suggested that free binary nanoparticles at 40 mg ml-1took 300 min to dechlorinate 600 ppm of TCP, whereas rGO-entangled Fe-Ni particles at the same mass took only 190 min to dechlorinate when the pH was maintained at near neutral. In addition, experiments on the reuse of the catalyst with respect to removal efficiency were carried out, and the results implied that, compared to free form, rGO-entangled nanoparticles exemplify more than 98% of removal efficacy even after 5 times of exposure to 600 ppm TCP concentration. The reduction in percentage removal was observed after the sixth exposure. A sequential dechlorination pattern was assessed and confirmed using high-performance liquid chromatography. Further, the phenol-enriched aqueous phase is exposed toBacillus licheniformisSL10, which degrades the phenol effectively within 24 h. In conclusion, the prepared binary nanoparticles, both in free as well as in rGO-entangled forms, effectively dechlorinate 2,4,6-TCP contaminations in the aqueous phase, but with differences in removal duration. Entanglement also makes it easier to reuse the catalyst. Furthermore, microbial phenol degradation allows the aqueous phase to be free of 2, 4, and 6-TCP contamination and allows for the reuse of treated water.

Evidence for complex iron oxides in the deep mantle from FeNi(Cu) inclusions in superdeep diamond.

The recent discovery in high-pressure experiments of compounds stable to 24-26 GPa with Fe4O5, Fe5O6, Fe7O9, and Fe9O11 stoichiometry has raised questions about their existence within the Earth's mantle. Incorporating both ferric and ferrous iron in their structures, these oxides if present within the Earth could also provide insight into diamond-forming processes at depth in the planet. Here we report the discovery of metallic particles, dominantly of FeNi (Fe0.71Ni0.24Cu0.05), in close spatial relation with nearly pure magnetite grains from a so-called superdeep diamond from the Earth's mantle. The microstructural relation of magnetite within a ferropericlase (Mg0.60Fe0.40)O matrix suggests exsolution of the former. Taking into account the bulk chemistry reconstructed from the FeNi(Cu) alloy, we propose that it formed by decomposition of a complex metal M oxide (M4O5) with a stoichiometry of (Fe3+2.15Fe2+1.59Ni2+0.17Cu+0.04)Σ=3.95O5 We further suggest a possible link between this phase and variably oxidized ferropericlase that is commonly trapped in superdeep diamond. The observation of FeNi(Cu) metal in relation to magnetite exsolved from ferropericlase is interpreted as arising from a multistage process that starts from diamond encapsulation of ferropericlase followed by decompression and cooling under oxidized conditions, leading to the formation of complex oxides such as Fe4O5 that subsequently decompose at shallower P-T conditions.

A sensitive fluorescence detection strategy for H2O2 and glucose by using aminated Fe-Ni bimetallic MOF as fluorescent nanozyme.

An aminated Fe-Ni bimetallic metal-organic framework (Fe3Ni-MOF-NH2) with both peroxidase-like activity and fluorescence properties was developed. Fe3Ni-MOF-NH2 possessed the enhanced peroxidase-like activity through the enhanced electron transfer process and hydroxyl radical (·OH) generation. It was found that the amino group endowed the material with fluorescent property and the metal site Ni in Fe3Ni-MOF-NH2 could also enhance the fluorescence emission intensity (Ex = 345 nm, Em = 452 nm). Based on the dual excellent performance of Fe3Ni-MOF-NH2, a novel sensitive fluorescence detection strategy for H2O2 and glucose was designed and achieved. First, Fe3Ni-MOF-NH2 converted H2O2 to ·OH by exerting peroxidase-like activity, and ·OH converts catechol to o-benzoquinone. Then, the amino group in Fe3Ni-MOF-NH2 connected to o-benzoquinone, which resulted in its fluorescence quenching. The detection limit of H2O2 was as low as 5 nM. Combined with glucose oxidase which can oxidize glucose and produce H2O2 the glucose could be indirectly determined with a detection limit of 40 nM. The method was applied to the detection of low-level glucose in human urine samples with good recoveries and reproducibilities.

A robust electrochemical sensor based on N,S-FeNi3/C for simultaneous detection of hydroquinone and arbutin in cosmetics.

For practical analysis and simultaneous detection of arbutin (AR) and hydrochinone (HQ) in cosmetics, an electrochemical sensor has been designed based on nitrogen and sulfur co-doped Fe-Ni alloy (N,S-FeNi3/C) nanoparticles. The N,S-FeNi3/C has been prepared for the first time via hydrothermal synthesis and high-temperature carbonization. N,S-FeNi3/C not only improves the charge transfer to the surface, but also provides rich active sites and fast ion diffusion rates owing to the iron and nickel bimetallic materials. In addition, the d-band structure of transition metals (nickel and iron) introduced by the N and S atoms exhibits an electronic structure similar to that of noble metal catalysts, thus enhancing electrocatalytic activity and increasing conductivity. Additionally, the double doping of S and N atoms significantly increases the active sites of carbon atoms; thus, N-S-FeNi3/C exhibits excellent electrochemical catalytic activity for the oxidation of AR and HQ. Further, the N,S-FeNi3/C sensor is used for the simultaneous determination of HQ and AR by square-wave pulse voltammetry. Distinct oxidation peaks of HQ and AR are observed at potentials of +0.028 V and +0.352 V (vs. SCE). The electrical signal increases linearly in the HQ concentration ranges of 0.1-100 µM and 0.05-70 µM for the simultaneous determination of AR and HQ with a detection limit as low as 0.0476 and 0.0135 µM (S/N = 3), respectively. Thus, rapid and accurate detection of AR and HQ in spiked cosmetics is successfully achieved, with a recovery ranging from 96.4 to 104.2%, and the relative standard deviation is lower than 3.8-4.0%.

Upgrading Pyrolytic Oil via Catalytic Co-Pyrolysis of Beechwood and Polystyrene.

This study aims to investigate the catalytic co-pyrolysis of beech wood with polystyrene as a synergic and catalytic effect on liquid oil production. For this purpose, a tubular semi-continuous reactor under an inert nitrogen atmosphere was used. Several zeolite catalysts were modified via incipient wetness impregnation using iron and/or nickel. The liquid oil recovered was analyzed using GC-MS for the identification of the liquid products, and GC-FID was used for their quantification. The effects of catalyst type, beechwood-to-polystyrene ratio, and operating temperature were investigated. The results showed that the Fe/Ni-ZSM-5 catalyst had the best deoxygenation capability. The derived oil was mainly constituted of aromatics of about 92 wt.% for the 1:1 mixture of beechwood and polystyrene, with a remarkably high heating value of around 39 MJ/kg compared to 18 MJ/kg for beechwood-based bio-oil. The liquid oil experienced a great reduction in oxygen content of about 92% for the polystyrene-beechwood 50-50 mixture in comparison to beechwood alone. The catalytic and synergetic effects were more realized for high beechwood percentages as a 75-25 beechwood-polystyrene mix. Regarding the temperature variation between 450 and 600 °C, the catalyst seemed to deactivate faster at higher temperatures, thus constituting a quality reduction in the pyrolytic oil in high-temperature ranges.

Bimetallic Fe/Ni nanoparticles derived from green synthesis for the removal of arsenic (V) in mine wastewater.

Since the incidences of arsenicosis have significantly increased worldwide in the last decade, remediation of arsenic (As) pollution is now imperative. In this study, calcined green synthesized Fe/Ni nanoparticles (C-Fe/Ni NPs) were evaluated for their efficacy for As (V) removal from aqueous solution. Under optimal experimental conditions As (V) removal efficiency reached 87.3%. Analysis of changes in the surface properties of C-Fe/Ni NPs before and after interaction with As (Ⅴ) using a range of advanced characterization techniques including IC-AFS, SEM-EDS, XPS and XRD revealed that the As removal mechanism involved only adsorption. Adsorption kinetics followed a pseudo-second order rate model (R2 > 0.986) and adsorption best fit the Langmuir isotherm model (R2 > 0.958). Thermodynamic studies indicated that adsorption was a spontaneous endothermic process. On the basis of these results, a removal mechanism of As (Ⅴ) by C-Fe/Ni NPs was proposed. Finally, the efficacy of the material for practical remediation of As from aqueous solution was assessed, including the influence of coexisting anions. While Cl-, NO3- and SO42- had little influence on As (V) removal, both H2PO4- and HCO3- significantly negatively affected removal.

Chromium speciation, mobility, and Cr(VI) retention-release processes in ultramafic rocks and Fe-Ni lateritic deposits of Greece.

Water contamination by geogenic hexavalent chromium is an emerging issue in areas developed on ultramafic rocks and their weathering products. In this study, samples of serpentinites, soil, and laterites were collected and analyzed for the levels of Cr species, distribution into phases of different mobility, mineralogy, Cr oxidation capacity, and leaching of Cr(VI). Total chromium (2176-21,929 mg kg-1) was mainly found in Cr spinels (~ 50% wt as Cr2O3) and Fe (hydr)oxides (2.5% wt). Total Cr(VI) contents (0.49-11.5 mg kg-1) increased from the serpentinites to the soil and lateritic deposit, i.e., during the advanced stages of weathering, which were accompanied by increased Cr mobility. Batch experiments of 500-h duration showed that Cr(VI) released in water at rates of 0.25-1.20 nM h-1. Rates were higher in water of pH 5.7 rather than pH 8.5, because more Cr(VI) was formed during the experimental period. Asbolane-type Mn oxides and Mn-bearing crystalline Fe oxides were responsible for Cr(III) oxidation. Most of the generated Cr(VI) (52-79% of total Cr(VI)) remained solid-bound by adsorption and/or precipitation processes. Because all samples had a self-capacity to oxidize Cr(III), it seems that retention processes will ultimately define the extent of geogenic Cr(VI) contamination of aquatic systems.

Reductive transformation of profenofos with nanoscale Fe/Ni particles.

Profenofos is an abundantly used organophosphate pesticide in agriculture but its excessive use may lead to hazardous effects on environment. Thus, the present study focused on the reductive transformation of this pesticide in the presence of Fe/Ni bimetallic nanoparticles by optimizing the process parameters such as stirring time, nanoparticles dose, pH, and initial pesticide concentration. The results of reductive transformation were compared with photodegradation studies. It was found that with the increase in UV irradiation time, the percent degradation was increased. After 660 min, a 78% photodegradation of 100 µM solution of pesticide was observed. On increasing the initial pesticide concentration to 200 µM, the maximum degradation was achieved in 570 min, but here, only 73% degradation was observed. The rates of photodegradation observed with 100 to 400 µM solutions were 1.4 × 10-3, 1.5 × 10-3, 1.5 × 10-3, and 5 × 10-4 min-1 respectively.In case of reductive transformation carried out in the presence of Fe/Ni bimetallic nanoparticles, the degradation was observed to be increased from 78 to 93.9% in only 180 min. A further increase in pesticide concentration led to a decrease in degradation. Under these conditions, the rate of reaction was found to be 1.09 × 10-2 min-1. A 93% degradation of profenofos was further increased to 98% when the quantity of nanoparticles was increased twice; hence, a significant reduction in time of irradiation was observed. Reductive transformation of pesticide thus provided an efficient and cheaper method for reducing the burden of profenofos from the environment.

Efficient composite chlorinated ethenes removal using gallic acid to enhance Fe/Ni nanoparticles activated persulfate.

As the representative volatile chlorinated hydrocarbons detected in wastewater, the removal of composite chlorinated ethenes is a major challenge in wastewater treatment. In the present study, an efficient removal system for composite chlorinated ethenes was reported, in which gallic acid was used to enhance the activation of persulfate by Fe/Ni nanoparticles. The influences of gallic acid-Fe/Ni and persulfate concentrations, initial pH value, reaction temperature, inorganic anions, and natural organic matters were evaluated in the composite chlorinated ethenes removal. Our results showed that the gallic acid-Fe/Ni-persulfate system with 9.0 mM of gallic acid-Fe/Ni and 30.0 mM of persulfate yielded about 100% trichloroethylene removal and 97.3%-98.6% perchloroethylene removal in the pH range of 3.0-12.0. Electron paramagnetic resonance analysis and radical quenching experiments indicated that SO4•- and •OH were the predominant radical species under acidic and alkaline conditions. Ultraviolet visible spectroscopy and inductively coupled plasma optical emission spectrometer tests revealed the Fe-gallic acid chelation could regulate the concentration of iron ions and improve the reactivity of gallic acid-Fe/Ni. These results demonstrated that the gallic acid-Fe/Ni-persulfate system was a promising strategy for treating composite chlorinated ethenes-containing wastewater.

Investigation of Fe-Ni Battery/Module for Grid Service Duty Cycles.

Iron-nickel (Fe-Ni) batteries are renowned for their durability and resilience against overcharging and operating temperatures. However, they encounter challenges in achieving widespread adoption for energy storage applications due to their low efficiency and the need for regular maintenance and electrolyte replacement, which adds to maintenance costs. This study evaluates and demonstrates the capabilities of Fe-Ni batteries for participating in grid energy storage applications. Stable performance was observed frequency regulation (FR) testing at 100% and 50% state of charge (SOC)s, while at 50% SOC, there was a 14% increase in efficiency compared to 100% SOC. Although 25% SOC achieved higher efficiency, limited cyclability was observed due to reaching the discharge cutoff voltage. Optimal SOC selection, battery monitoring, maintenance, and appropriate charging strategies of Fe-Ni batteries seem to be crucial for their FR applications. Fe-Ni batteries exhibit stable peak shaving (PS) results, indicating their suitability and reliability under various load conditions for PS testing. Extended cycling tests confirm their potential for long-term grid-scale energy storage, enhancing their appeal for PS and FR applications.

3D-printing of Fe-Ni bimetallic particles and their application in removal of arsenic from water.

Arsenic is a hazardous element found in water sources, and removing it is crucial for ensuring a safe environment and water quality. Iron-based metal oxides efficiently remove arsenic; however, their small particle sizes make separation from water difficult after arsenic removal. Furthermore, the growing global issue of polymer waste further complicates environmental concerns. Combining three-dimensional (3D) printing and adsorption technology by incorporating nanosized functional materials into supporting polymers offers a potential solution to address both challenges. In this study, we developed a 3D-printed adsorption material through the incorporation of synthesized Fe-Ni bimetallic particles into a supporting polymer using selective laser sintering (SLS) technology. This adsorbent's properties were examined through scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and zeta potential. Furthermore, its performance in removing As(III) and As(V), even at trace levels, was assessed under varied conditions. The 3D-printed adsorbent demonstrated excellent removal of As(III) at pH 6, and As(V) at pH 4, lowering their concentration below 10 µg/L, thereby adhering to the limit established by the World Health Organization (WHO). Both As(III) and As(V) fitted the Freundlich isotherm and pseudo-second-order model, suggesting potential heterogeneous and chemisorption processes. FT-IR indicated that the exchange of the -OH group of Fe-OH with oxyanions of As(III) and As(V) could be the adsorption mechanism. Additionally, thermodynamic evaluation unveiled an endothermic and non-spontaneous adsorption reaction. The 3D-printed adsorbent exhibited excellent reusability across recurring adsorption cycles. The combination of SLS 3D printing with Fe-Ni bimetallic particles produces structures that retain their functionality in removing both arsenic species present in water. This indicates the potential of the 3D-printed adsorbent for effective treatment of arsenic-contaminated water, offering remedies to challenges like handling small particle sizes, mitigating polymer waste, and addressing environmental concerns.

Characterisation of synthesised trimetallic nanoparticles and its influence on anaerobic digestion of palm oil mill effluent.

The augmentation of biogas production can be achieved by incorporating metallic nanoparticles as additives within anaerobic digestion. The objective of this current study is to examine the synthesis of Fe-Ni-Zn and Fe-Co-Zn trimetallic nanoparticles using the co-precipitation technique and assess its impact on anaerobic digestion using palm oil mill effluent (POME) as carbon source. The structural morphology and size of the synthesised trimetallic nanoparticles were analysed using a range of characterization techniques, such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX) . The average size of Fe-Ni-Zn and Fe-Co-Zn were 19-25.5 nm and 19.1-30.5 nm respectively. Further, investigation focused on examining the diverse concentrations of trimetallic nanoparticles, ranging from 0 to 50 mgL-1. The biogas production increased by 55.55% and 60.11% with Fe-Ni-Zn and Fe-Co-Zn trimetallic nanoparticles at 40 mgL-1 and 20 mgL-1, respectively. Moreover, the lowest biogas of 11.11% and 38.11% were found with 10 mgL-1 of Fe-Ni-Zn and Fe-Co-Zn trimetallic nanoparticles. The findings of this study indicated that the trimetallic nanoparticles exhibited interactions with anaerobes, thereby enhancing the degradation process of palm oil mill effluent (POME) and biogas production. The study underscores the potential efficacy of trimetallic nanoparticles as a viable supplement for the promotion of sustainable biogas generation.

Comprehensive investigation of isotherm, RSM, and ANN modeling of CO2 capture by multi-walled carbon nanotube.

Chemical vapor deposition was used to produce multi-walled carbon nanotubes (MWCNTs), which were modified by Fe-Ni/AC catalysts to enhance CO2 adsorption. In this study, a new realm of possibilities and potential advancements in CO2 capture technology is unveiled through the unique combination of cutting-edge modeling techniques and utilization of the recently synthesized Fe-Ni/AC catalyst adsorbent. SEM, BET, and FTIR were used to analyze their structure and morphology. The surface area of MWCNT was found to be 240 m2/g, but after modification, it was reduced to 11 m2/g. The modified MWCNT showed increased adsorption capacity with higher pressure and lower temperature, due to the introduction of new adsorption sites and favorable interactions at lower temperatures. At 25 °C and 10 bar, it reached a maximum adsorption capacity of 424.08 mg/g. The optimal values of the pressure, time, and temperature parameters were achieved at 7 bar, 2646 S and 313 K. The Freundlich and Hill models had the highest correlation with the experimental data. The Second-Order and Fractional Order kinetic models fit the adsorption results well. The adsorption process was found to be exothermic and spontaneous. The modified MWCNT has the potential for efficient gas adsorption in fields like gas storage or separation. The regenerated M-MWCNT adsorbent demonstrated the ability to be reused multiple times for the CO2 adsorption process, as evidenced by the study. In this study, a feed-forward MLP artificial neural network model was created using a back-propagation training approach to predict CO2 adsorption. The most suitable and efficient MLP network structure, selected for optimization, consisted of two hidden layers with 25 and 10 neurons, respectively. This network was trained using the Levenberg-Marquardt backpropagation algorithm. An MLP artificial neural network model was created, with a minimum MSE performance of 0.0004247 and an R2 value of 0.99904, indicating its accuracy. The experiment also utilized the blank spreadsheet design within the framework of response surface methodology to predict CO2 adsorption. The proximity between the Predicted R2 value of 0.8899 and the Adjusted R2 value of 0.9016, with a difference of less than 0.2, indicates a high level of similarity. This suggests that the model is exceptionally reliable in its ability to predict future observations, highlighting its robustness.

The Influence of Al and Nb on the Low Oxygen Pressure Pre-Oxidation Behavior of Fe-35Ni-20Cr-xAl-yNb Alloys at 1000 °C.

To investigate the impact of Al and Nb elements on the formation of a protective oxide layer on the surface of Fe-35Ni-20Cr-xAl-yNb (x = 0, 2, 4, 6 wt.%; y = 0, 1, 2 wt.%) alloys, their oxidation behavior was examined at 1000 °C, 10-17 atm. and 10-25 atm. oxygen pressure, and the oxidation mechanism was analyzed by Factsage and Pandat calculations. Enhancing the Al content at 10-17 atm. inhibited the generation of FeCr2O4 on the alloy surface and increased the Al content in the M2O3 layer. When the Al content exceeded 6 wt.%, the oxide film partially peeled off. It was found that the addition of Nb increased the activity of Cr and Al and decreased the activity of Ni and Fe and promoted the formation of Al2O3, and the appearance of Nb2O5 in the subsurface layer increased the density of the oxide film. In addition, under an oxygen pressure of 10-25 atm., the only protective layer on the surface of the alloy comprised of Al2O3. The experimental results demonstrated that the Fe-35Ni-20Cr-4Al-2Nb alloy generated a continuous and dense Al2O3 protective film, and the reduction in oxygen pressure and the addition of Nb elements were favorable for selective external oxidation of Al2O3.

Iron-Nickel synergistic catalysis growth of (Fe,Ni)9S8/Ni3S2@N,S codoped carbon bridged nanowires enhanced oxygen evolution reaction performance.

Improving the conductivity of the electrocatalyst itself is essential for enhancing its performance. In this work, N, S-rich 6-thioguanine (TG) is selected as the ligand to synthesize a Fe, Ni bimetallic porous coordination polymer (PCP), which is then derived to fabricate N,S codoped carbon (NSC)-coated (Fe,Ni)9S8/Ni3S2 bridged nanowires. The (Fe,Ni)9S8/Ni3S2@NSC bridged nanowires obtained through bimetallic synergistic catalysis and self-sulfurization processes not only introduced additional electrocatalytic active sites but also significantly enhance the overall conductivity of the catalyst due to the interconnected nanowire structure. The resulting (Fe,Ni)9S8/Ni3S2@NSC demonstrates remarkable oxygen evolution reaction (OER) performance, exhibiting an overpotential as low as 252 mV at a current density of 10 mA cm-2. This work proposes a novel strategy for enhancing the overall conductivity of catalysts by growing bridged nanowires, providing valuable insights and inspiration for the design and preparation of advanced transition metal sulfide electrocatalysts.

Dechlorination of 2,4-dichlorophenol by Fe/Ni nanoparticles: the pathway and the effect of pH and the Ni mass ratio.

ABSTRACTThe dechlorination of 2,4-dichlorophenol (2,4-DCP) by a nanoscale Fe/Ni material was investigated at room temperature. 2,4-DCP can be removed more quickly by an Fe/Ni material with 2% Ni. Fe/Ni exhibited excellent adsorption and reduction efficiency toward 2,4-DCP in an aqueous solution over a wide range of pH values. The removal rate of 2,4-DCP exceeded 95% in 60 min in the pH range of 3.0-9.0, and more than 75% was dechlorinated to phenol (CA). The degradation pathway of 2,4-DCP was confirmed based on analysis of the intermediate and end products. A portion of 2,4-DCP was first dechlorinated with a chlorine atom to produce 2-chlorophenol and 4-chlorophenol, and then dechlorination was performed sequentially to form CA. The other portion of 2,4-DCP was dechlorinated to remove two chlorine atoms simultaneously to generate CA. The investigations are essential to the application of iron-based remediation technology.

Sulfur dots and iron co-doped nickel-based metal-organic frameworks with high nanozyme activity for the colorimetric determination of α-glucosidase activity.

Alpha-glucosidase (α-Glu) plays a crucial role in regulating the normal physiological function of the body; therefore, α-Glu activity detection is crucial in clinical studies. In this study, a nickel-based metal-organic framework (Ni-MOF) co-doped with sulfur dots (SDs) and iron (Fe) was designed and constructed for the colorimetric detection of α-Glu. The SDs/Fe/Ni-MOF shows a very low Michaelis-Menten constant (0.0466 mM) for H2O2, suggesting a very high affinity for H2O2. Additionally, the free radicals generated by the nanozyme-catalyzed reaction were analyzed, and the feasibility of the nanozyme-catalyzed process was further verified using density functional theory. The bimetallic (Fe and Ni) can improve the catalytic activity of the material, and sulfur can improve the affinity with the substrate to further enhance the catalytic performance. Notably, hydroquinone (HQ) inhibits nanozyme activity, whereas α-Glu hydrolyzes alpha-arbutin (α-Arb) and subsequently produces HQ. Therefore, this study developed a method for detecting α-Glu activity using α-Arb as a substrate. This method has high selectivity, a wide detection range (1.00-100 U L-1), and a low detection limit (0.525 U L-1). Finally, the method was used to α-Glu activity detected in serum samples with good accuracy. This study provides a new method for the detection of α-Glu.

In-situ exsolution of Fe-Ni alloy catalysts for H2 and carbon nanotube production from microwave plasma-initiated decomposition of plastic wastes.

The management of plastic wastes has become an urgent issue due to the overconsumption of single-use plastic products. As a promising avenue for plastic waste valorization, chemical recycling by converting plastics into value-added products has attracted tremendous attention. In this paper, the Fe-Ni alloy catalysts via in-situ exsolution were employed for the straightforward microwave plasma-initiated decomposition of plastic wastes for high yield H2 and carbon nanotubes. The partial substitution of Fe by Ni promoted in-situ exsolution of alloy nanoparticles homogeneously. Specifically, characterization results showed that the introduction of Ni modulated metal-support interaction, which further affected the crystalline phase, nanoparticle size and oxygen vacancies. The exsolved Fe-Ni alloy catalyst exhibited the highest catalytic activity, over which 96 % hydrogen of plastic wastes rapidly evolved out in the form of gas products accompanied with high-purity carbon nanotubes. The H2 yield was 415 mmol·g-1Hplastic, which exhibited an over 2 times improvement versus the supported catalyst. Moreover, the successive cycle test displayed the potential for converting plastic wastes into H2-rich fuels and high-quality CNTs continuously. Generally, the in-situ exsolution strategy of Fe-Ni alloy catalysts contributed to the sustainable and high-efficient recycling of plastic wastes into H2-rich gas products and carbon nanotubes under microwave plasma.

Local Maxima in Martensite Start Temperatures in the Transition Region between Lath and Plate Martensite in Fe-Ni Alloys.

In the binary Fe-rich Fe-Ni system, martensite start temperatures MS decrease from 500 to 200 K when Ni concentrations increase from 20 to 30 at.%. It is well known that alloys with Ni concentrations below 28.5 at.% exhibit lath martensite (LM) microstructures (athermal transformation, small crystals, accommodation by dislocations). Above this concentration, plate martensite (PM) forms (burst-like transformation, large crystals, accommodation by twins). The present work is based on a combination of (i) ingot metallurgy for the manufacturing of Fe-Ni alloys with varying Ni-concentrations, (ii) thermal analysis to measure phase transformation temperatures with a special focus on MS, and (iii) analytical orientation imaging scanning electron microscopy for a quantitative description of microstructures and crystallographic features. For Ni-concentrations close to 28.5 at.%, the descending MS-curve shows a local maximum, which has been overlooked in prior works. Beyond the local maximum, MS temperatures decrease again and follow the overall trend. The local maximum is associated with the formation of transition martensite (TM) microstructure, which exhibits LM and PM features. TM forms at higher MS temperatures, as it is accommodated by simultaneous twinning and dislocation slip. An adopted version of the Clausius-Clapeyron equation explains the correlation between simultaneous accommodation and increased transformation temperatures.