Search Results (1,246)

There is an urgent need to develop sustainable approaches for the remediation of contaminated soil as well as to promote sustainable practices for waste management. Here, we provide the first evaluation of the performance of two types of iron nanoparticles (NA and NH) obtained from olive mill wastewater for the remediation of an acidic multi-contaminated soil, including metal(loid)s, PCBs, and a flame retardant (TCPP). Their efficiency was then compared against that of a commercial nanoscale zero-valent iron (NS) through a one-month microcosm experiment employing two doses of each nanomaterial. The impact of the treatments on key soil physicochemical properties, metal(loid) availability, PCB and TCPP concentrations, and soil phytotoxicity was assessed. All treatments reduced soil acidity. Regarding organic contaminants, bioremediation of TCPP was enhanced by all nanomaterials, particularly NH, whereas NA was the only treatment that significantly reduced PCB concentration under the tested conditions. NS achieved the highest rates of metal(loid) immobilization (63–100%); NH was most beneficial for soil fertility and immobilized As, Ni, and Pb (100, 38, and 53%, respectively), whereas NA was only effective for Pb (21–49%). The low dose of both NA and NH improved the germination index (66 and 61%, respectively), reducing soil phytotoxicity. These results highlight the potential of valorizing olive mill wastewater for soil remediation, thereby contributing to the principles of the Circular Economy. Full article

Catalytic dry reforming of ethanol offers a sustainable pathway for syngas and hydrogen production through CO₂ utilization, though its efficiency depends heavily on the strategic synthesis of catalysts and the optimization of reaction parameters. This study employs Box–Behnken Design (BBD) and Response Surface Methodology (RSM) to optimize hydrogen yield from CO₂ reforming of ethanol over a Yttrium-promoted Ni-Co/MCM-41 catalyst. The catalyst was synthesized using sequential wet impregnation method and characterized for its physicochemical properties. The catalyst was tested in fixed-bed reactor using experimental data obtained from BBD considering the effects of temperature (550–700 °C), ethanol flowrate (0.5–1 mL/min) and CO₂ flowrate (15–30 mL/min) on the hydrogen yield. The experimental conditions were optimized using RSM quadratic model. The characterization revealed that the ordered mesoporous nature of the MCM-41 is maintained providing a high surface area of 597.75 m²/g for the catalyst. The addition of Yttrium as a promoter facilitates the formation of well crystallized nanoparticles. Maximum hydrogen yield of 85.09% was obtained at 700 °C, 20.393 mL/min and 0.877 mL/min for temperature, CO₂ and ethanol flowrate, respectively. The predicted hydrogen yield obtained is strongly correlated with the actual values as indicated by R² of 0.9570. Full article

Ni-based catalysts have been extensively investigated for lignin hydrogenation; however, they often exhibit limited phenol selectivity and poor catalytic stability. To address these challenges, we introduced Cu as a promoter, resulting in the development of NiCu/ZSM-5 catalysts with significantly enhanced phenol selectivity and durability. Characterization studies revealed that Cu species form an alloy structure with Ni, which effectively suppresses the sintering of Ni nanoparticles during the catalytic process, thereby maintaining consistent performance over multiple reaction cycles. Furthermore, the Cu-Ni alloy demonstrated improved hydrogen activation capability while reducing overall H₂ uptake, leading to a marked increase in phenol selectivity compared to the Cu-free Ni/ZSM-5 catalyst. As a result, the Ni₁Cu₁/ZSM-5 (Ni/Cu molar ratio = 1:1) catalyst achieved a lignin conversion of 69.8% and a phenol selectivity of 84.4%, with negligible performance degradation over 8 cycles. The strategy presented in this work may offer an effective approach for enhancing the performance of industrial catalysts in lignin upgrading processes. Full article

This investigation has yielded a remarkably efficient metallic catalyst. Copper (Cu), cobalt (Co), and nickel (Ni) nanoparticles were concurrently deposited onto micron-sized aluminum (µAl) through a displacement reaction, resulting in the formation of [nCu+nCo+nNi]/µAl composites. The interfacial layer of the nanocomposite facilitates the creation of efficient oxygen transport pathways, significantly augmenting thermal release. In the context of the ADN/AP oxidizer, the [nCu+nCo+nNi]/µAl configuration demonstrates a substantial synergistic catalytic effect, reducing its thermal decomposition temperature by an impressive 104.1 °C. Combustion experiments have corroborated that this composite markedly enhances flame intensity, combustion temperature, and the burning rate of the ADN/AP system. The underlying thermal-oxidative mechanism was elucidated through comprehensive thermal analysis of the composite both prior to and following a heat treatment at 1100 °C. Moreover, through an integration of thermal analysis and combustion experiments, the catalytic mechanism of [nCu+nCo+nNi]/µAl on the thermolysis of ADN/AP was elucidated, and a plausible reaction pathway under thermal stimulation was proposed (e.g., ${\mathrm{NH}}_4{\mathrm{ClO}}_4+{{\mathrm{NH}}_4\mathrm{N}({\mathrm{NO}}_2)}_2\stackrel{\mathrm{Cu},\mathrm{Co},\mathrm{Ni}}{\to }{\mathrm{N}}_2+{\mathrm{H}}_2\mathrm{O}+\mathrm{HCl}+{\mathrm{O}}_2+\left[\mathrm{O}\right]$). The developed nanocomposite significantly enhances the performance of oxidizers, presenting considerable potential for a wide array of applications in solid propellants. Full article

CO₂ valorization from real feedstocks through CH₄ tri-reforming (CH₄-TR), combining steam reforming (SR), dry reforming (DR), and partial oxidation (CPO) of methane in a single process, is a desirable strategy for greenhouse gas mitigation and syngas (CO + H₂) production. NiCo/γ−Al₂O₃ catalysts prepared by impregnation at different relative metal contents (Ni₅₀Co₅₀ and Ni₃₀Co₇₀) were investigated for CH₄-TR in a fixed-bed reactor under conventional heating and characterized by XRD, FESEM, and Raman spectroscopy after catalytic runs. This study focused on the role of the Ni/Co ratio and feed composition on selectivity for CO₂ valorization, syngas yield, and deactivation resistance. Both the catalysts showed high activity, with a superior performance of Ni₅₀Co₅₀ confirming Ni metal species as the active sites. While in DR, a slow deactivation occurred due to coke deposition, in CH₄-TR, the addition of small O₂ and/or H₂O amounts stabilized activity and selectivity due to surface carbon removal. Large O₂ and H₂O amounts strongly inhibited CO₂ conversion due to competition with CPO and SR, in the order CPO ≥ DR > SR. Interestingly, the stoichiometric CH₄-to-oxidants ratio favored the DR pathway, giving very high CO₂ conversion. Modulating CH₄ addition into real flue mixtures renders CH₄-TR on NiCo/γ-Al₂O₃ catalysts a favorable strategy for effective valorization of CO₂ industrial or biomass-derived streams. Full article

Mechanical forces, chemical and electrochemical reactions, and environmental variables can all lead to surface degradation of parts. Composite coatings can be applied to these materials to enhance their surface characteristics. Recently, nickel-based composite coatings have gained greater attention because of their remarkable wear resistance. The efficiency, precision, and affordability of this process make it a popular method. In addition, electroplating nickel-based composites offers a more environmentally friendly alternative to traditional dangerous coatings such as hard chrome. Tribological and wear characteristics are highly dependent on several variables, such as particle parameters, deposition energy, fluid dynamics, and bath composition. Mass loss, coefficient of friction, hardness, and roughness are quantitative properties that provide useful information for coating optimization and selection. Under optimized electrodeposition conditions, the Ni-SiC-graphite coatings achieved a 57% reduction in surface roughness (Ra), a 38% increase in microhardness (HV), and a 25% reduction in wear rate (Ws) compared to pure Ni coatings, demonstrating significant improvements in tribological performance. Overall, the incorporation of SiC nanoparticles was found to consistently improve microhardness while graphite or MoS₂ reduces friction. Differences in wear rate among studies appear to result from variations in current density, particle size, or test conditions. Furthermore, researchers run tribology studies and calculate the volume percentage using a variety of techniques, but they fall short in providing a sufficient description of the interface. This work primarily contributes to identifying gaps in tribological research. With this knowledge and a better understanding of electrodeposition parameters, researchers and engineers can improve the lifespan and performance of coatings by tailoring them to specific applications. Full article

This work presents a detailed analysis of polysulfone (PSF) based mixed matrix membranes (MMMs) modified with NiMOF@MGO for water purification. Magnetic iron oxide nanoparticles were synthesized and incorporated into the NiMOF@GO framework, with successful formation confirmed by FT-IR, XRD, BET, TGA, and SEM analyses. Membranes were prepared via phase inversion and modified with varying NiMOF@MGO contents. SEM, AFM, and contact angle analyses demonstrated enhanced membrane hydrophilicity with increasing MOF concentration, reducing the contact angle from 59.74° (0.05 wt%) to 49.70° (0.2 wt%). The highest flux of 117.85 L/m²·h was observed for the PMM-0.2 membrane. Heavy metal removal was most efficient at pH 6, with the PMM-0.1 membrane achieving 95.97% and 95.92% rejection for Pb²⁺ and Cu²⁺, respectively. In oil-water separation, PMM-0.1 exhibited optimal performance, with a water flux of 45.84 L/m²·h. Antifouling tests showed the PMM-0.2 membrane had the highest flux recovery of 85.97%, indicating improved fouling resistance. Overall, incorporation of NiMOF@MGO significantly enhanced membrane hydrophilicity, flux, selectivity and antifouling performance, demonstrating its potential for advanced water purification applications. Full article

Ni–ySiC system (where y = 0.001, 0.005, and 0.015 wt.%) composite materials with enhanced mechanical properties have been fabricated and comprehensively investigated. The composites were synthesized using a combined technology involving preliminary mechanical activation of powder components in a planetary mill followed by consolidation via spark plasma sintering (SPS) at 850 °C. The microstructure and phase composition were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The physico-mechanical properties were evaluated by density measurements (hydrostatic weighing), three-point bending tests (25 °C and 400 °C), and Young’s modulus measurement using an ultrasonic method (25–750 °C). It was found that the introduction of ultralow amounts of SiC nanoparticles (0.001 wt.%) leads to an extreme increase in flexural strength: by 115% at 20 °C (up to 1130 MPa) and by 86% at 400 °C (up to 976 MPa) compared to pure nickel. Microstructural analysis revealed the formation of an ultrafine-grained structure (0.15–0.4 µm) with the presence of pyrolytic carbon and probable nickel silicide interlayers at the grain boundaries. Thermodynamic and kinetic modeling, including the calculation of chemical potentials and diffusion coefficients, confirmed the possibility of reactions at the Ni/SiC interface with the formation of nickel silicides (Ni₂Si, NiSi) and free carbon. The scientific novelty of the work lies in establishing a synergistic strengthening mechanism combining the Hall–Petch, Orowan (dispersion), and solid solution strengthening effects, and in demonstrating the property extremum at an ultralow content of the dispersed phase (0.001 wt.%), explained from the standpoint of quantum-chemical analysis of phase stability. The obtained results are of practical importance for the development of high-strength and thermally stable nickel composites, promising for application in aerospace engineering. Full article

Male reproductive disorders and declining fertility rates play an important role in birth rates, and their impact on future populations makes them one of the most serious public health issues of this century. Defects in spermatogenesis are the most common manifestation of male infertility, and exposure to environmental pollutants has been suggested as a potential cause. Nanomaterials, due to their unique physicochemical properties and widespread application, have raised growing concerns about their potential reproductive toxicity. Studies have shown that nickel nanoparticles (Ni NPs) have reproductive toxicity in male rats and mice, especially sperm damage. This study aimed to explore the male reproductive toxicity of Ni NPs and the role of mitochondrial fission in mouse spermatocytes (GC-2). Our results showed that Ni NPs induced the damage of mitochondrial structure and function in GC-2 cells and disrupted intramitochondrial homeostasis, thereby resulting in enhanced Dynamin-related protein 1(Drp1)-mediated mitochondrial fission and cell apoptosis, along with aggravated cytotoxicity and obvious reproductive toxicity. The mitochondrial division inhibitor 1(Mdivi-1) and lentiviral-transfected low expression of Dnm1l can significantly alleviate the germ cell toxicity caused by Ni NPs, suggesting a certain therapeutic effect. The novelty of this study lies in its systematic demonstration that Drp1-mediated mitochondrial division is a core pathogenic mechanism of Ni NP-induced male reproductive toxicity, and the validation of both pharmacological inhibition and genetic silencing as effective intervention strategies. Therefore, this study offers a reference for expanding the reproductive toxicity effect of Ni NPs and potential molecular mechanisms and provides an important basis for finding potential targets and treatment of Ni NPs. Full article

In this study, metallic nanoparticle polymeric PLA composites such as Silver (Ag)+PLA, Nickel (Ni)+PLA, Copper (Cu)+PLA, and Copper Oxide (CuO)+PLA were developed using injection moulding to study the antimicrobial efficacy of the developed polymeric composites against several Gram-positive and Gram-negative pathogenic strains like Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Salmonella Poona, Pseudomonas aeruginosa, and Escherichia coli. SEM and EDS were used to identify the surface morphology and elemental composition of Ni+PLA, Ag+PLA, Cu+PLA, and CuO+PLA composites, which showed specific metal dispersion and surface roughness, which have effects on antimicrobial activity. Thermal characteristics analysed by TGA and DSC showed an increase in thermal stability and crystallisation properties because of nanoparticle integration. All four composites demonstrated high efficacy against the tested bacterial strains, achieving an overall reduction of approximately 70% in all samples. A more substantial decrease of 98% was observed across all strains in each composite, except for a slightly lower efficacy of 97% in the Ni+PLA and Ag+PLA composites against Enterococcus faecalis and Pseudomonas aeruginosa. The potential for such antimicrobial materials and their characteristics make the current investigation particularly innovative for the medical field, and such antimicrobial materials would be extremely beneficial to reduce HAIs and drug-resistant organisms that otherwise complicate patient care and lower the efficiency and quality of health care provided. Full article

There is a growing demand for biocompatible, non-toxic nanomaterials with specific functional properties, including catalytic activity. In this study, magnetic iron oxide nanoparticles were synthesized via chemical co-precipitation in the presence of polyethylene glycol (PEG). PEG was used as a coating agent to reduce particle agglomeration. Comprehensive characterization of the synthesized nanocomposites was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX) and vibrating sample magnetometry (VSM). SEM studies confirmed the nanosized structure of the particles with an average diameter of 20–60 nm. The saturation magnetization values were 57.37 emu·g⁻¹ for nFe₃O₄-PEG6000, 11.95 emu·g⁻¹ for nFe₃O₄-PEG4000 and 3.97 emu·g⁻¹ for nCo_0.5Ni_0.5Fe₂O₄-PEG4000. In addition to their high magnetic properties, ferrofluids exhibited peroxidase-like activity, which makes them highly suitable for bioanalytical and biomedical use. The Michaelis–Menten constant (K_M) for hydrogen peroxide ranged from 1.15 to 4.98 mM. Transmission electron microscopy (TEM) proved the penetration of the nano-ferrofluids into the yeast cells of Ogataea polymorpha. The studied nano-ferrofluids were found to be non-toxic at concentrations up to 0.2 mg·mL⁻¹ for both prokaryotic and eukaryotic cells, showing no inhibitory effect on the growth of the bacterium Escherichia coli, the yeast Ogataea polymorpha, or animal and human cell lines. These results indicate that the advantages of synthetic nano-ferrofluids—including peroxidase-like activity, strong magnetic properties, cost-effective synthesis, stability, and low toxicity—make the synthesized nano-ferrofluids highly promising for future biomedical and bioanalytical applications. Full article

The green synthesis of silver nanoparticles (AgNPs) by bacteria is a strategic route for sustainable nanobiotechnology; however, the genomic and biochemical mechanisms that make it possible remain poorly defined. In this study, bacteria native to silver-bearing mine tailings in Taxco (Mexico) were isolated, capable of tolerating up to 5 mM of AgNO₃ and producing extracellular AgNPs. Spectroscopic (430–450 nm) and structural (XRD, fcc cubic phase) characterization confirmed the formation of AgNPs with average sizes of 17–21 nm. FTIR evidence showed the participation of extracellular proteins and polysaccharides as reducing and stabilizing agents. Genomic analyses assigned the isolates as Lysinibacillus fusiformis 31HCl and L. xylanilyticus G1-3. Genome mining revealed extensive repertoires of genes involved in uptake, transport, efflux and detoxification of metals, including P-type ATPases, RND/ABC/CDF transporters, Fe/Ni/Zn uptake systems, and metal response regulators. Notably, homologues of the silP gene, which encode Ag⁺ translocator ATPases, were identified, suggesting convergent adaptation to silver-rich environments. Likewise, multiple nitroreductases (YodC, YdjA, YfKO) were detected, candidates for mediating electron transfer from NAD(P)H to Ag⁺. These findings support the role of Lysinibacillus as microbial nanofactories equipped with specialized molecular determinants for silver tolerance and AgNP assembly, providing a functional framework for microorganism-based nanobiotechnology applications. Full article

Dark fermentative hydrogen production is constrained by challenges including low hydrogen yield and operational instability. Magnetic nanoparticles (MNPs) have emerged as promising additives for enhancing biohydrogen production due to their unique physicochemical characteristics, such as high specific surface area, excellent electrical conductivity, and inherent magnetic recyclability. This review systematically compares the enhancement mechanisms of MNPs in two distinct microbial systems: pure cultures and mixed cultures. In pure cultures, MNPs function primarily at the cellular and molecular levels through the following: (1) serving as sustained-release sources of essential metallic cofactors like Fe and Ni to promote hydrogenase synthesis and activation; (2) acting as efficient electron carriers that facilitate intracellular and extracellular electron transfer; and (3) redirecting central carbon metabolism toward high-hydrogen-yield acetate-type fermentation. In mixed cultures, which are more representative of practical applications, MNPs operate at the ecological level through the following: (1) modifying microenvironmental niches to exert selective pressure that enriches hydrogen-producing bacteria, such as Clostridium; (2) forming conductive networks that promote direct interspecies electron transfer and strengthen syntrophic metabolism; and (3) enhancing system robustness via toxin adsorption and pH buffering. Despite promising phenomenological improvements, critical knowledge gaps remain, including unclear structure–activity relationships of MNPs, insufficient quantification of electron transfer pathways, unknown genetic regulatory mechanisms, and overlooked magnetobiological effects. Future research should integrate electrochemical monitoring, multi-omics analyses, and advanced characterization techniques to deepen the mechanistic understanding of nanomaterial–microbe interactions. This review aims to provide theoretical insights and practical strategies for developing efficient and sustainable MNP–microorganism hybrid systems for scalable biohydrogen production. Full article

In this work, nickel oxide nanoparticles (NiO NPs) were synthesized sonochemically in the ionic liquid 1,2-(propanediol)-3-methylimidazolium hydrogen sulfate ([PDOHMIM⁺][HSO₄⁻]) at different loadings (8 wt.%, 15 wt.%, and 30 wt.%), and subsequently coated with polyethylene glycol (PEG). Structural characterization (XRD, FTIR, TEM, TGA) confirmed a cubic NiO spinel phase with an average crystallite size of ~8 nm, which increased to 20–28 nm after PEG coating. Electrical measurements (100 Hz–1 MHz) showed that AC conductivity (σAC) increased with both frequency and NiO content, whereas the dielectric constant (ε′) and loss tangent (tan δ) decreased with frequency. DFT calculations (B3LYP/6–311+G(2d,p)) on the [PDOHMIM⁺][HSO₄⁻] ion pair showed that there were strong hydrogen bonds, an uneven charge distribution, and stable electrostatic interactions that help keep NiO NPs stable and spread them evenly in the ionic liquid. In general, both experimental and theoretical studies show that PEG-coated [NiO NPs + IL] nanostructures exhibit improved dielectric stability, enhanced interfacial polarization, and tunable electronic properties. Full article

We report a non-enzymatic electrochemical sensing platform for creatinine based on a nickel-nanoparticle/carbon-quantum-dot (NiNP–CQD) hybrid interface. In this system, the analytical signal originates from the direct electrocatalytic oxidation of creatinine mediated by the Ni(II)/Ni(III) redox couple (Ni(OH)₂/NiOOH), which forms during electrochemical activation of nickel in alkaline media. These redox centers act as catalytic sites that oxidize creatinine without requiring enzymes or biomolecular labels. The CQDs provide a conductive sp²-rich network with abundant oxygenated groups that promote homogeneous nucleation and dispersion of NiNPs, enhancing both surface area and electron-transfer efficiency. Electrochemical characterization of the modified electrodes was performed using the ferricyanide/ferrocyanide redox couple as the electron-transfer probe. Structural and microscopic characterization confirms uniform NiNP deposition on the CQD layer, while electrochemical studies demonstrates that the composite outperforms CQDs or NiNPs alone in current density, linearity, and resistance to active-site saturation. The resulting sensor exhibits a wide linear range (10–1000 µM), high area-normalized sensitivity (1.41 µA µM⁻¹ cm⁻²), and a low detection limit of 5 µM. Selectivity tests reveal minimal interference from common physiological species. By explicitly leveraging a catalyst-driven, enzyme-free oxidation pathway, this NiNP–CQD architecture provides a robust, stable, and scalable platform for clinically relevant creatinine detection. Full article