Search Results (27)

The content of modified materials in multicomponent gel phase change materials directly affects their performance characteristics. To investigate the influence of different contents of modified materials on the performance features of Na₂HPO₄·12H₂O-based multicomponent Gel Phase Change Materials, four single factors (Na₂SiO₃·9H₂O, C₃₅H₄₉O₂₉, KCl, and nano-α-Fe₂O₃) and their interactions were selected as influencing factors. Using the Taguchi method with an L₂₇(3¹³) orthogonal array, multi-step melt–blending experiments were conducted to prepare a novel multi-component phase change material. The characteristics of the new multi-component phase change material, including supercooling degree (ΔT), phase change temperature (T_m), latent heat of phase change (ΔH_m), and cooling time (CT), were obtained. In addition, characterization techniques such as DSC, SEM, FT-IR, and XRD were employed to analyze its thermal properties, microscopic morphology, chemical stability, and crystal structure. Based on the experimental results, the signal-to-noise ratio (S/N) was used to rank the influence of each factor on the quality characteristics, and the p-value from analysis of variance (ANOVA) was employed to evaluate the significance of each factor on the performance characteristics. Then, the effects of each significant factor on the characteristics of the multiple gel phase change materials were analyzed in detail, and the optimal mixing ratio of the new multiple gel phase change materials was selected. The results showed that Na₂SiO₃·9H₂O, KCl, and α-Fe₂O₃ were the most critical process parameters. This research work enriches the selection of composite gel phase change materials for solar greenhouses and provides guidance for the selection of different modified material contents using Na₂HPO₄·12H₂O as the starting material. Full article

The disinfection of drinking water is essential for eliminating pathogens and preventing waterborne diseases. However, this process generates various disinfection byproducts (DBPs), which toxicological research indicates can have detrimental effects on living organisms. Moreover, the safety of these DBPs has not been sufficiently assessed, underscoring the need for a comprehensive evaluation of their toxic effects and associated health risks. Compared to traditional methods for studying the toxicity of pollutants, emerging electrochemical sensing technologies offer advantages such as simplicity, speed, and sensitivity, presenting an effective means for toxicity research on pollutants. However, challenges remain in this field, including the need to improve electrode sensitivity and reduce electrode costs. In this study, a pencil graphite electrode (PGE) was modified with carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and nano-iron (III) oxide (α-Fe₂O₃) to fabricate a low-cost electrode with excellent electrocatalytic performance for cell-active substances. Subsequently, a novel cellular electrochemical sensor was constructed for the sensitive detection of the toxicity of three drinking water DBPs. The half inhibitory concentration (IC₅₀) values of 2-chlorophenylacetonitrile (2-CPAN), 3-chlorophenylacetonitrile (3-CPAN), and 4-chlorophenylacetonitrile (4-CPAN) for HepG2 cells were 660.69, 831.76, and 812.83 µM, respectively. This study provides technical support and scientific evidence for the toxicity detection and safety assessment of emerging contaminants. Full article

MnZn ferrite powders were prepared based on the novel nano in situ composite method and through chemical sol-spray drying–calcination technology. The precursor powders were calcined at 1060 °C at different calcination times (1–9 h) to research the influences of the calcination time on MnZn ferrite powders. The research results revealed that all samples had similar morphologies composed of fine particles. The pure MnZn ferrite spinel phase can only be obtained when the calcination time does not exceed 3 h. Otherwise, some α-Fe₂O₃ or γ-Fe₂O₃ impurities will appear. The particle size descended with an increasing calcination time and then ascended. After 3 h of preservation, the smallest particle size was obtained, and it exhibited a unimodal distribution. The saturation magnetization (M_s) increased at first and decreased later with an increasing calcination time, and the optimal value (53.4 emu/g) was reached after holding for 3 h. In view of this work, the optimal calcination time is 3 h. Full article

Fe₂O₃/g-C₃N₄ nano-heterostructures for photocatalytic degradation of NOR (norfloxacin) were successfully prepared by combining co-precipitation and calcination methods. The g-C₃N₄, Fe₂O₃, and different composite ratios of Fe₂O₃/g-C₃N₄ (FeCNs) were characterized by XRD, SEM, XPS, UV-vis DRS, PL, and electrochemical tests, and the mechanism of photocatalytic degradation of NOR was analyzed. The results indicated that the semiconductor was attached to the surface of g-C₃N₄ in the form of α-Fe₂O₃ crystal with good crystalline structure. The composite of Fe₂O₃ with g-C₃N₄ increased the specific surface area of the material, effectively reduced the band gap, strengthened the photogenerated e⁻/h⁺ pair separation, and improved the photocatalytic performance of the composite. The photocatalytic degradation of NOR was consistent with the quasi-primary reaction kinetic model. Among them, FeCN-25wt% showed the optimal photocatalytic degradation of NOR (72.3%) with the largest degradation rate (k = 0.00900 min⁻¹). The Fe₂O₃/g-C₃N₄ composite structure is inferred to be a Z-type heterojunction. Full article

In order to improve the performance of white rot fungi, especially the model species Phanerochaete chrysosporium in tetrabromobisphenol A (TBBPA) degradation, the strategy of synergizing Phanerochaete chrysosporium with nano iron oxides was considered; however, the effects of different nano iron oxides on Phanerochaete chrysosporium are still unknown. In this study, 20 nm γ-Fe₂O₃, 30 nm α-Fe₂O₃, 20 nm Fe₃O₄, and 200 nm Fe₃O₄ were used, and the fungal growth, oxidative stress, and ability to degrade TBBPA were monitored. The results showed that the addition of four nano iron oxides did not inhibit the growth of Phanerochaete chrysosporium. The effective antioxidant defense system of Phanerochaete chrysosporium could cope with almost all oxidative pressure induced by 200 nm Fe₃O₄. But when the size of nano iron oxide became significantly smaller or when the type of iron oxide changed from Fe₃O₄ to Fe₂O₃, a higher intracellular hydrogen peroxide (H₂O₂) content, lower intracellular superoxide dismutase (SOD) and catalase (CAT) activities and higher extracellular lactate dehydrogenase (LDH) activity were induced. When nano iron oxides synergized with Phanerochaete chrysosporium, the removal of TBBPA in all groups was slightly improved and mostly due to the degradation of TBBPA, with smaller iron oxides showing more enhancement for the degradation of TBBPA, while 200 nm Fe₃O₄ only enhanced the adsorption of TBBPA. The enhanced degradation of TBBPA showed no significant correlation with lignin-degrading enzyme activities but was closely correlated with the intracellular H₂O₂ concentration. Full article

Biogenic synthesis using medicinal plants has less harmful effects as compared to the chemical synthesis of nanoparticles. Here, for the first time, we successfully demonstrated the eco-friendly synthesis of zinc oxide nanoparticles (ZnO NPs) using an aqueous extract of Cissus antractica. The green synthesis method offers great potential for developing new medications that enhance drug bioavailability. The current work highlighted the cytotoxicity, cell death, and routes of apoptosis in lung cancer cells (A549) and inflammatory effects through synthesizing zinc oxide nanoparticles (ZnO NPs) from the Cissus antractica plant using an eco-friendly methodology. UV–visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy (EDS) were also used to characterize the synthesized ZnO nanoparticles. The average size of the NPs was 100 nm, and the NPs were crystalline in nature, as confirmed by FE-TEM and XRD analysis, respectively. In addition, the morphology of the nanoparticles analyzed by FE-TEM showed a spherical shape. The cell viability assay indicated that CA-ZnO NPs are non-toxic to normal cell lines at concentrations up to 20 µg/mL but showed significant toxicity in the A549 cell line. The nanoformulation also increased the ROS generation level in A549 lung cancer cells, and cellular apoptosis was confirmed via Hoechst and PI staining. The CA-ZnO NPs showed significant colony inhibition as well as cell migration ability that highlighted the CA-ZnO NPs as an anticancer agent. Additionally, this study demonstrated that NPs reduced the production of reactive oxygen species (ROS) and enhanced the expression of genes for BAX accumulation by releasing Cyto-c, but decreased Bcl-2 gene expression via the mitochondrial-mediated apoptosis pathway. In addition, the anti-inflammatory effect was also investigated; the CA-ZnO NPs showed significant NO inhibition ability with suppression of pro-inflammatory cytokines (TNF-α, iNOS, COX-2, IL-6, IL-8). In conclusion, Cissus antractica can be a source of significant Nano drugs with more advanced research in order to develop future anti-inflammatory and anticancer medications. Full article

Researchers have made efforts to develop high-productivity photocatalysts for photocatalytic hydrogen production to reduce the problem of a lack of energy. Bulk semiconductor photocatalysts mainly endure particular limitations, such as low visible light application, a quick recombination rate of electron–hole pairs, and poor photocatalytic efficiency. The major challenge is to improve solar-light-driven heterostructure photocatalysts that are highly active and stable under the photocatalytic system. In this study, the proposed nano-heterojunction exhibits a great capacity for hydrogen production (871.2 μmol g⁻¹ h⁻¹), which is over 8.1-fold and 12.3-fold higher than that of the bare MoS₂ and bare α-Fe₂O₃ samples, respectively. It is demonstrated that the MoS₂/α-Fe₂O₃ heterojunction gives rise to an enhanced visible light response and accelerated photoinduced charge carrier separation. This work provides an improved visible light absorption efficiency and a narrowed energy band gap, and presents a “highway” for electron–hole pairs to promote transfer and inhibit the combination of photoinduced charge carriers for the utilization of nano-heterojunction photocatalysts in the field of hydrogen production. Full article

In order to improve photocatalytic activity and maximize solar energy use, a new composite material Fe₂O₃/P₂Mo₁₈ was prepared by combining polyoxometalates (P₂Mo₁₈) with Fe₂O₃ nanosheets. FT-IR, XRD, XPS, SEM, TEM, UV-vis, EIS, and PL were used to characterize the composite material, and nano-Fe₂O₃ of different sizes and morphologies with a controllable absorption range was prepared by adjusting the reaction time, and, when combined with P₂Mo₁₈, a composite photocatalyst with efficient visible light response and photocatalytic activity was constructed. The EIS, Bode, and PL spectra analysis results show that the Fe₂O_3/P₂Mo₁₈ composite material has outstanding interfacial charge transfer efficiency and potential photocatalytic application possibilities. Model reactions of methylene blue (MB) and Cr (VI) photodegradation were used to evaluate the redox activity of Fe₂O₃/P₂Mo₁₈ composites under simulated visible light. The photocatalytic degradation rate was as high as 98.98% for MB and 96.86% for Cr (VI) when the composite ratio was Fe₂O₃/P₂Mo₁₈-5%. This research opens up a new avenue for the development of high-performance photocatalysts. Full article

This article describes spark plasma sintering of ceramics based on silicon carbide with nanoadditives, as follows: MnO_nano 5.5 wt. % + Al₂O_3nano 2.0 wt. % + SiC_nm (37–57 wt. %) + SiC_µm (31–51 wt. %) + SiO_2µm 4.5 wt. %. Sintering was carried out at 2000 °C. The diffraction pattern of the analyzed sample showed the presence of silicon carbide with a hexagonal crystal lattice. Residual amounts of rhombohedral SiC, α-Fe, and a solid solution of silicon in iron were also found. The method of thermogravimetric analysis established the change in mass, heat flow, temperature of the samples, and the change in the partial pressures of gases during the experiment. Samples obtained by SPS show a higher density of the material at the level of 3.3 g/cm³, average mechanical strength of 454 MPa, and microhardness of 35 GPa, compared with samples obtained by liquid-phase sintering. The SPS method also made it possible to obtain materials with a higher density (by 8%) and practically no significant crystal growth compared to samples obtained by liquid phase sintering. The results of the study facilitate the achievement of a combination of new approaches to the design of compositions and the technology of manufacturing SiC ceramics, which significantly expands their areas of application. Full article

The symmetric nano morphologies, asymmetric electronic structures, and as well as the heterojunctions of the developed photocatalytic systems perform a vital role in promoting light absorption, separation of electron and hole pairs and charge carrier transport to the surface when exposed to near-infrared (NIR) light. In this present work, we synthesized hematite (α-Fe₂O₃) nanoparticles (NPs) by a facile hydrothermal method and studied their structural, optical, and photocatalytic properties. Powder X-ray diffraction (XRD) confirmed the rhombohedral phase of the α-Fe₂O₃ NPs, and Fourier transform infrared spectroscopy (FT-IR) was used to investigate symmetric and asymmetric stretching vibrations of the functional groups on the surface of the catalysts. The optical bandgap energy was estimated to be 2.25 eV using UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and scanning electron microscopy (SEM) images indicated sphere like morphology. The oxidation and reduction properties of α-Fe₂O₃ NPs were analyzed by cyclic voltammetry (CV). The α-Fe₂O₃ NPs were utilized for the degradation of methylene blue (MB) dye under natural sunlight. The experimental results demonstrate that the degradation efficiency was achieved at 33% in 2 h, and the pseudo-first-order rate constant was calculated to be 0.0033 min⁻¹. Full article

Novel Fe-Al-SiO₂ (FAS) poly-coagulants were prepared by the ball milling method using ferrous sulfate, aluminum sulfate, hydrophobic silica, and sodium carbonate as raw materials. The optimal preparation conditions and effects of preparation parameters on removal efficiencies were obtained by Response Surface Methodology (RSM) and Analysis of Variance (ANOVA). Removal efficiencies were investigated by employing FAS as the poly-coagulant for algae-laden water. Furthermore, obtained FAS samples were characterized by SEM, FTIR, XRD, and TGA. Results showed that the optimal preparation conditions were n(Fe):n(Al) of 2:1, m(Si):m(Fe+Al) of 1:2, and n(CO₃²⁻):n(Fe+Al) of 1.75:1, and the most significant influencing factor was n(CO₃²⁻):n(Fe+Al). FAS₁₃ prepared under the above condition had the highest coagulation efficiency for simulated algae-laden water. Removal efficiencies for OD₆₈₀, TP, and residual Al and Fe concentrations were 92.86%, 90.55%, 0.142 mg/L, and 0.074 mg/L, respectively. Nano-sized spherical particles, excellent thermal stability, and functional groups such as Al–O–Si, Fe–O–Si, and Fe–OH, corresponding to Al₂Si₂O₅(OH)₄, Fe₇Si₈O₂₂(OH)₂, and Fe₂(OH)₂CO₃, were observed in FAS₁₃. The coagulation performance of FAS₁₃ was splendid when applied in real algae-laden water. The removal rates of TP, OD₆₈₀, turbidity, and Chl-α were above 93.87%. The residual Al concentration was at the range of 0.057–0.128 mg/L. Full article

The main objective of the present research work is to assess the biological properties of the aqueous plant extract (ACAE) synthesised silver nanoparticles from the herbal plant Ageratum conyzoides, and their biological applications. The silver nanoparticle syntheses from Ageratum conyzoides (Ac-AgNPs) were optimised with different parameters, such as pH (2, 4, 6, 8 and 10) and varied silver nitrate concentration (1 mM and 5 mM). Based on the UV–vis spectroscopy analysis of the synthesised silver nanoparticles, the concentration of 5 mM with the pH at 8 was recorded as the peak reduction at 400 nm; and these conditions were optimized were used for further studies. The results of the FE-SEM analysis recorded the size ranges (~30–90 nm), and irregular spherical and triangular shapes of the AC-AgNPs were captured. The characterization reports of the HR-TEM investigation of AC-AgNPs were also in line with the FE-SEM studies. The antibacterial efficacies of AC-AgNPs have revealed the maximum zone of inhibition against S. typhi to be within 20 mm. The in vitro antiplasmodial activity of AC-AgNPs is shown to have an effective antiplasmodial property (IC₅₀:17.65 μg/mL), whereas AgNO₃ has shown a minimum level of IC₅₀: value 68.03 μg/mL, and the Ac-AE showed >100 μg/mL at 24 h of parasitaemia suppression. The α-amylase inhibitory properties of AC-AgNPs have revealed a maximum inhibition similar to the control Acarbose (IC₅₀: 10.87 μg/mL). The antioxidant activity of the AC-AgNPs have revealed a better property (87.86% ± 0.56, 85.95% ± 1.02 and 90.11 ± 0.29%) when compared with the Ac-AE and standard in all the three different tests, such as DPPH, FRAP and H₂O₂ scavenging assay, respectively. The current research work might be a baseline for the future drug expansion process in the area of nano-drug design, and its applications also has a lot of economic viability and is a safer method in synthesising or producing silver nanoparticles. Full article

Alumina and zirconia thin films modified with colored nano-Fe_xO_y pigments were sintered by the flash-lamp-annealing method. We selected a nano α-Al₂O₃ and micron α-Al₂O₃ bimodal mixture as the base precursor material, and we doped it with 5 vol% of Fe_xO_y red/brown/black/yellow pigments. The coatings were deposited from nanoparticle dispersions both on glass and on flexible metal foil. The characteristics of the thin films obtained with the use of various additives were compared, including the surface morphologies, optical properties, crystallinities, and structures. Flash lamp annealing was applied with the maximum total energy density of 130 J/cm² and an overall annealing time of 7 s. Based on the simulated temperature profiles and electron-microscopy results, a maximum annealing temperature of 1850 °C was reached for the red Al₂O₃: Fe₂O₃ ceramic film. The results show that red α-Fe₂O₃ pigments allow for the achievement of maximum layer absorption, which is effective for flash lamp sintering. It was also possible to use the selected red α-Fe₂O₃ particles for the flash-lamp-assisted sintering of ZrO₂ on a 30 µm-thin flexible stainless-steel substrate. Full article

The removal of chlorinated pollutants from water by nanoparticles is a hot topic in the field of environmental engineering. In this work, a novel technique that includes the coupling effect of n-Fe/Ni and its transformation products (FeOOH) on the removal of p-chloronitrobenzene (p-CNB) and its reduction products, p-chloroaniline (p-CAN) and aniline (AN), were investigated. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to characterize the nano-iron before and after the reaction. The results show that Fe⁰ is mainly oxidized into lath-like lepidocrocite (γ-FeOOH) and needle-like goethite (α-FeOOH) after 8 h of reaction. The coupling removal process and the mechanism are as follows: Fe⁰ provides electrons to reduce p-CNB to p-CAN and then dechlorinates p-CAN to AN under the catalysis of Ni. Meanwhile, Fe⁰ is oxidized to FeOOH by the dissolved oxygen and H₂O. AN is then adsorbed by FeOOH. Finally, p-CNB, p-CAN, and AN were completely removed from the water. In the pH range between 3 and 7, p-CAN can be completely dechlorinated by n-Fe/Ni within 20 min, while AN can be nearly 100% adsorbed by FeOOH within 36 h. When the temperature ranges from 15 °C to 35 °C, the dechlorination rate of p-CAN and the removal rate of AN are less affected by temperature. This study provides guidance on the thorough remediation of water bodies polluted by chlorinated organics. Full article

In this paper, the study of the influence of the matrix structure (mxm) of thin-film, rotation angle (α), magnetic field (B), and size (D) of Fe₂O₃ nanoparticle on the magnetic characteristic quantities such as the magnetization oriented z-direction (M_zE), z-axis magnetization (M_z), total magnetization (M_tot), and total entropy (S_tot) of Fe₂O₃ nanocomposites by Monte-Carlo (MC) simulation method are studied. The applied MC Metropolis code achieves stability very quickly, so that after 30 Monte Carlo steps (MCs), the change of obtained results is negligible, but for certainty, 84 MCs have been performed. The obtained results show that when the mxm and α increase, the magnetic phase transition appears with a very small increase in temperature Néel (T_Ntot). When B and D increase, T_Ntot increases very strongly. The results also show that in Fe₂O₃ thin films, T_Ntot is always smaller than with Fe₂O₃ nano and Fe₂O₃ bulk. When the nanoparticle size is increased to nearly 12 nm, then T_Ntot = T = 300 K, and between TNtot and D, there is a linear relationship: T_Ntot = −440.6 + 83D. This is a very useful result that can be applied in magnetic devices and in biomedical applications. Full article