Energy Dispersive X-ray Spectroscopy Analysis Research Articles

Enhanced photocatalytic degradation of Rhodamine B using polyaniline-coated XTiO3(X = Co, Ni) nanocomposites

In this study, novel polyaniline-coated perovskite nanocomposites (PANI@CoTiO3 and PANI@NiTiO3) were synthesized using an in situ oxidative polymerization method and evaluated for the photocatalytic degradation of Rhodamine B (RhB) a persistent organic pollutant. The nanocomposites displayed significantly enhanced photocatalytic efficiency compared to pure perovskites. The 1%wt PANI@NiTiO3 achieved an impressive 94% degradation of RhB under visible light after 180 min, while 1wt.% PANI@CoTiO3 reached 87% degradation under UV light in the same duration. X-ray diffraction (XRD) confirmed that the crystalline structures of CoTiO3 and NiTiO3 remained intact post-polymerization. At the same time, Fourier transform infrared spectroscopy (FTIR) verified the successful deposition of PANI through characteristic functional group vibrations. Diffuse reflectance spectroscopy (DRS) revealed reduced band gaps of 2.63 eV for 1wt.% PANI@NiTiO3 and 2.46 eV for 1wt.% PANI@CoTiO3, enhancing light absorption across UV and visible ranges. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis demonstrated the uniform distribution of PANI, ensuring consistent surface activity and efficient charge transfer. The photocatalytic test confirmed a pseudo-first-order degradation mechanism. The study elucidates the degradation mechanism through intermediate identification via HPLC-MS analysis, highlighting N-de-ethylation, aromatic ring cleavage and eventual mineralization into CO2 and H2O as critical pathways. Furthermore, the 1wt.%PANI@NiTiO3 nanocomposite demonstrated excellent stability and recyclability, maintaining its degradation efficiency over four consecutive cycles with minimal change. These findings highlight the potential of PANI@XTiO3 nanocomposites for sustainable and efficient wastewater treatment, addressing diverse environmental challenges by tailoring photocatalysts to specific light sources.

Investigating the Li2O-Al2O3-B2O3 matrix: A promising approach for immobilizing radioactive waste.

Dealing with radioactive waste, particularly from various industrial processes, poses significant challenges. This paper explores the use of lithium aluminate borate (Li-Al-B) glass matrix as an alternative method for immobilizing radioactive waste, focusing specifically on waste generated in tin smelting industries, known as tin slag. The study primarily concentrates on transforming tin slag, a byproduct abundant in Natural Occurring Radioactive Material (NORM), into a stable and safe form for disposal. The experimental procedures involve blending different compositions of tin slag and Li-Al-B glass, followed by melting them at 1000°C for 1h and then rapidly cooling to room temperature. The resulting glass waste identifies an optimal weight percentage of waste loading (typically ranging from 25% to 45%), to minimize volume while effectively immobilizing radioactive material. Notably, the glass waste exhibited an amorphous phase during the product consistency test (PCT) process, demonstrating the fundamental relationship between waste composition and immobilization efficiency. Energy dispersive X-ray spectroscopy (EDX) analysis confirmed a uniform distribution of major elements within the glass waste, underscoring its structural integrity. Furthermore, the dissolution rate of key elements in the glass waste is analyzed, revealing a robust resistance to leaching under varying pH conditions. The normalized mass loss of Boron (B), Lithium (Li), and Aluminum (Al) consistently remain below established glass limits (<2 gm-2), indicative of the glass's exceptional durability. In conclusion, these findings highlight the potential effectiveness of Li-Al-B glass as a versatile host material for immobilizing solid radioactive waste, extending beyond its initial application with tin slag. By highlighting the positive qualities of this matrix, the study emphasizes its potential flexibility in accommodating various types of solid waste matrices.

Flexible and lead-free polymer composites for X-ray shielding: comparison of polyvinyl chloride matrix filled with nanoparticles of tungsten oxides.

Polymer nanocomposites have been investigated as lightweight and suitable alternatives to lead-based clothing. The present study aims to fabricate flexible, lead-free, X-ray-shielding composites using a polyvinyl chloride (PVC) matrix and different nanostructures. Four different nanostructures containing impure tungsten oxide, tungsten oxide (WO3), barium tungstate (BaWO4), and bismuth tungstate (Bi2WO6) were synthesized through various methods. Subsequently, their morphological characteristics were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Also, energy-dispersive X-ray spectroscopy (EDS) analysis was performed to establish the presence of the filler in the PVC matrix. Two different weight ratios of these nanostructures (20% wt and 50% wt) were used to produce the PVC composites. To investigate attenuation parameters, the prepared composites were irradiated with X-rays at tube voltages of 40, 80, and 120kV. The results showed that the PVC composites containing 20% wt Bi2WO6 had the highest linear attenuation coefficient (µ) at all three voltages. Furthermore, they had the lowest half-value layer (HVL), tenth-value layer (TVL), and 0.5mm equivalent lead thickness values at each of the three voltages. The PVC composites containing 50% wt Bi2WO6 had attenuation coefficients greater than those reported for PbO at all three X-ray voltages. Among the studied tungsten nanostructures, bismuth tungstate had the best attenuation performance for X-ray protection. Additionally, this composite is light, flexible, and non-toxic, making it a promising alternative to lead aprons.

Mechanochemical Synthesis of Phase-Pure CsCu2I3 and Cs3Cu2I5 Phosphors Regulated by Polar Solvents and Their Application in Tunable Chromaticity LEDs.

Lead halide perovskites have garnered interest in light-emitting diode (LED) applications due to their strong emission and tunable properties. However, conventional synthesis methods involve energy-intensive thermal processes and hazardous organic solvents, raising environmental concerns. In this study, we report a simple and eco-friendly mechanochemical approach that produces phase-pure blue-emitting Cs3Cu2I5 (emission at 440 nm) and yellow-emitting CsCu2I3 (emission at 570 nm) phosphors through polarity modulation and control of grinding duration. Our comprehensive analysis of the phase transitions during mechanochemical synthesis reveals that pure Cs3Cu2I5 was synthesized from a 3:2 precursor molar ratio in ethanol for 30 min, while pure CsCu2I3 was obtained from a 1:2 precursor molar ratio in an aqueous solution for 7.5 min. Moreover, Raman spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy analyses confirmed that phase-pure phosphors were achieved through these methods. Finally, we fabricated a series of color-adjustable LEDs by mixing Cs3Cu2I5 and CsCu2I3 phosphors in different proportions. This demonstrates the potential of our mechanochemical synthesis for the efficient, large-scale production of next-generation lighting materials with tunable emission.

Gingival keratinocyte adhesion on atomic layer-deposited hydroxyapatite coated titanium.

This study aimed to evaluate the effects of the atomic layer deposited hydroxyapatite (ALD-HA) coating of the titanium (Ti) surface on human gingival keratinocyte (HGK) cell adhesion, spreading, viability, and hemidesmosome (HD) formation. Grade 2 square-shaped Ti substrates were used (n = 62). Half of the substrates were ALD-HA coated, while the other half were used as non-coated controls (NC). The ALD-HA surface was characterized with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis. The initial cell adhesion and HD formation of HGKs were evaluated after a 24-h cultivation period. The cell proliferation was assessed by cultivating cells for 1, 3, and 7d. The expression levels of the integrin mediating cell adhesion were detected with the Western Blot method. In addition, cell spreading and expression of the proteins mediating cell adhesion were imaged using a confocal microscope. SEM-EDS analysis demonstrated the formation of HA on the ALD-HA surfaces. The relative cell attachment was significantly higher (p < .05) on the ALD-HA compared to the NC surface after 1 and 3 d of cell culture. No significant difference was found in integrin α6 or β4 expression. The microscope evaluation showed significantly increased cell spreading with peripheral HD expression on ALD-HA compared to the NC surfaces (p = .0001). Moreover, laminin γ2 expression was significantly higher on the ALD-HA than on the NC surfaces (p < .001). Compared to the NC Ti surface, the ALD-HA coating has favorable effects on HGK proliferation, growth, and cell spreading. This indicates that the ALD-HA coating has good potential for improving mucosal attachment on implant surfaces.

Memory Effect of Double Oxides Compared to Simple Ion Exchange for Controlled Fluoride Ion Capture and Release

A layered double hydroxide (LDH) containing Mg and Al was synthesized from a nitrate solution using a coprecipitation method. The resulting material exhibited a homogeneous structure, which, upon calcination at 450 °C, was converted into a layered double oxide (LDO). When rehydrated in a fluoride-containing aqueous solution, the original hydroxide structure was successfully regenerated, demonstrating the LDH’s memory effect. During this transformation, fluoride anions from the solution were incorporated into the interlayer galleries to maintain electroneutrality, as confirmed by energy-dispersive X-ray spectroscopy (EDS) analysis. Separately, the process was tested in the presence of ethanol, which significantly enhanced the incorporation of fluoride ions into the interlayer spaces. The material’s potential for controlled fluoride release was evaluated by monitoring its release into demineralized water. For comparison, a simple ion-exchange process was carried out using the as-synthesized MgAl LDH. The memory effect mechanism displayed a notably higher fluoride incorporation capacity compared to the ion-exchange process. Among all the specimens, the sample reconstructed in the presence of ethanol exhibited the highest fluoride ion content. Fluoride release studies revealed a two-phase pattern: an initial rapid release within the first three hours, followed by a substantially slower release over time.

Extraction of cellulose nanocrystals from date seeds using transition metal complex-assisted hydrochloric acid hydrolysis.

In this study, the role of a transition metal complex in improving hydrolysis efficiency during nanocellulose production was analysed. Cellulose nanocrystals (CNCs) were extracted from date seeds by incorporating a copper metal complex during HCl hydrolysis. In contrast to traditional HCl hydrolysis at moderate conditions, which yielded only microcrystalline cellulose (MCC), this approach resulted in the extraction of CNCs with a 10% improved yield compared to MCC. Morphological analysis using scanning electron microscopy revealed semi-spherical shaped particles, while transmission electron microscopy showed CNCs with a particle size ranging from 70 to 80nm. Dynamic light scattering analysis indicated a significant reduction in average particle size from 900nm to 121nm, highlighting the remarkable efficiency of using the copper metal complex in combination with HCl to improve yield and particle size. Energy dispersive X-ray spectroscopy analysis confirmed the purity of the CNCs, with no residual copper detected. Thermal analysis demonstrated the high stability of the CNCs, with an initial decomposition temperature (Tonset) of 274.02°C and an activation energy (Ea) of 219.90kJ/mol. X-ray diffraction analysis revealed that the CNCs exhibited high degree of crystallinity (Crl=72.03%). Disseminating these research findings will significantly impact the CNCs production industry, facilitating improved yields and the production of nano-sized fibers through the utilization of transition metal complexes alongside hydrolysis solvents.

Synthesis, Structure, and Electrochemical Performance of Bi-induced Stabilization of MnO2 Cathodes for Use in Highly Acidic Aqueous Electrolytes (pH

MnO2 cathode materials are widely studied in alkaline and neutral aqueous electrolytes. In these mediums, the MnO2 cathode shows suboptimal performance limited by dissolution and electrochemically inactive compound formation, leading to capacity fading. This study explores the enhancement of MnO2 cathode performance through Bi3+ ion doping (0, 1, 2.5, 5, and 10mol%) in a highly acidic electrolyte (pH < 2). By incorporating up to 10mol% Bi ions into the MnO2 structure, we significantly improved specific capacity and capacity retention stability. Energy-dispersive X-ray spectroscopy (EDX) analysis revealed a uniform dispersion of Bi3+ ions throughout the MnO2 cathode after electrochemical cycling, contributing to performance enhancements. X-ray photoelectron spectroscopy (XPS) results indicated that Bi3+ ion concentration from 1 to 10mol% stabilises Mn3+ within the MnO2 lattice. Also, Bi3+ ion doping promotes the formation of a 2×2 tunnel structured α-MnO2 phase. Electrochemical impedance spectroscopy results demonstrated a reduction in double-layer and overall bulk capacitance. These findings suggest that Bi3+ ion doping effectively enhances MnO2 electrochemical performance and could enhance its use in aqueous metal-ion batteries.

Study of Crystal Structure, Lattice Strain, and Elemental Content of Natural Iron Sand Nanoparticles Synthesized by the Coprecipitation Method

This study was conducted to investigate the synthesis of magnetite nanoparticles from iron sand collected from the Bah Bolon River in Indonesia, using the coprecipitation method with NaOH and NH4OH as precipitants. The results showed that based on SEM-EDX (scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy) analysis, the Fe content of the raw iron sand, initially at 34.76%, increased to 45.50% following synthesis with NH4OH, indicating enhanced purity in the final product. SEM observations found average particle sizes of approximately 53 nm for nanoparticles synthesized with NaOH and 20 nm for those synthesized with NH4OH. X-ray diffraction (XRD) analysis confirmed that the synthesized nanoparticles retain the magnetite (Fe3O4) phase with a face-centered cubic (FCC) spinel structure. Crystallite size calculations using the Scherrer equation yielded average crystallite sizes of 80.194 nm for NaOH-synthesized samples and 15.124 nm for NH4OH-synthesized samples, demonstrating that NH4OH favors the formation of smaller crystallites. Lattice strain analysis through the Williamson-Hall method showed positive tensile strain values for all samples, indicating structural tension within the crystal lattice. The NH4OH-synthesized nanoparticles had slightly higher lattice strain, suggesting that synthesis conditions impact both crystallite size and lattice tension. In conclusion, this study demonstrated that NH4OH was more effective than NaOH in producing high-purity, small-crystallite magnetite nanoparticles from natural iron sand, with potential implications for enhanced material properties.

Green Synthesis of ZnO Nanoparticles Using Delonix elata &amp; Gynura cusimbua Leaf Extracts and Evaluating Their In-vitro Antibacterial Properties

With an increasing focus on the application of nanoparticles in the field of research, this study aims to evaluate the in-vitro antibacterial properties of chemically and green synthesized zinc oxide nanoparticles (ZnO NPs) from two plant sources Delonix elata and Gynura cusimbua. The bioactive compounds present in the leaf extracts were utilized to stabilize the nanoparticles. UV-Visible spectrophotometry (UV-Vis), X-ray diffraction (XRD), and Scanning electron microscopy (SEM) were used to elucidate the optical and structural properties of the synthesized ZnO NPs. The in-vitro antibacterial potential of ZnO NPs were evaluated by Agar Disc Diffusion Assay against two pathogenic bacterial strains: Bacillus cereus, a gram-positive animal pathogen and Pseudomonas syringae, a gram-negative plant pathogen, making it a well-rounded approach. The UV–visible spectrum was measured in 250 – 400 nm range and the crystallite structure was analyzed via XRD. SEM-EDS (Energy-Dispersive X-ray Spectroscopy) analysis confirmed the nanostructures with partial nanoflakes and aggregates for all three samples of the synthesized ZnO NPs. The D. elata ZnO NPs showed relatively greater antimicrobial activity against both the bacterial strains than that of G. cusimbua ZnO NPs. Consequently, plant-based NPs may be an excellent strategy for developing versatile and environmentally friendly biomedical products. They have an added advantage due to their pre-existing medicinal properties, which make them a more suitable alternative to the broadly used chemically synthesized nanoparticles. KEY WORDS: Delonix elata, Gynura cusimbua, Zinc oxide Nanoparticle, antimicrobial activity, Bacillus cereus, Pseudomonas syringae.

Mesoporous Silica-Carbon Composites with Enhanced Conductivity: Analysis of Powder and Thin Film Forms.

The resistivity of the silica SBA-15 type can be significantly improved by forming a thin layer of carbon on the pore surface. This is possible through the carbonization reaction of a surfactant used as a structure-directing agent in the synthesis of mesostructured silica materials. The synthesis of this type of silica-carbon composite (SBA-C) is based on the use of sulfuric acid to create a carbon layer from surfactant molecules encapsulated in silica mesopores. The action of sulfuric acid takes place through dehydration and sulfonation reactions, which promote the formation of aromatic structures and favor crosslinking processes. The same procedure was applied to prepare MTF-C composites based on mesostructured thin films (MTFs). Compared to pure silica materials, these silica-carbon composites exhibit reduced pore diameter and volume while maintaining morphology and structure. The pore structure characteristics were obtained by scanning and transmission electron microscopy, X-ray energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, thermogravimetry, and isothermal sorption analysis. The composite obtained after carbon layer formation exhibited enhanced conductivity in comparison to pure silica SBA-15. The resistivity of SBA-C composite material after annealing at 800 °C under a nitrogen atmosphere decreased to 1980 Ωcm in comparison with pure SBA-15.

Upcycling of Eggshell Waste into Calcium Phosphates for Use in Sustainable Biomedical Engineering Applications

Eggshells are an inorganic waste, and their accumulation rate is increasing globally, complicating waste management. However, the European Union defines eggshells as low-risk material that can be recycled and reused safely in other applications. Their chemical composition renders them an attractive precursor of calcium phosphate materials (CaPs). Because of their remarkable biocompatibility and capacity for natural degradation, CaPs are frequently employed in biomedical engineering applications. In this research, the wet precipitation method was employed for fabricating CaP powder. Initially, the eggshells were processed into CaCO3 powder and then reacted with HCl to obtain CaCl2 (aq). This reacted with Na2HPO4 to obtain a precipitate that was filtered and dried. The precipitate in powder form underwent X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis to evaluate its microstructure, and elemental and phase composition. The results indicated that the recovered powder was brushite.

Structural, morphological, mechanical, and electrical studies of N. nucifera fibres.

The Powder X-ray diffraction (PXRD) data of Nelumbo Nucifera fibre is utilized to study multifaceted properties. Rietveld refinement was carried out along with cellulose phase. The crystallite size was computed using the Scherrer equation, and through first principle calculations, it has been illustrated and concluded that the size is not ellipsoidal, as previously suggested by other researchers; rather, it exhibits a multidimensional shape. Treloar's principle was used to create a 6×6 elastic tensor matrix, which was analysed with the Elastic Tensor Analysis (EALTE) tool that showed the fibre is anisotropic. The dielectric properties were measured in relation to frequency and temperature. It was found that conductivity increases with an increase in frequency and temperature. Functional Data Analysis (FDA) and regression analyses were employed to determine the correlation among various parameters. Fourier Transform Infrared Spectroscopy (FTIR) studies confirm that the lotus fibre is made up of cellulose. Scanning Electron and Transmission Electron Microscopy images unveiled that the lotus fibre exhibits structural stability characterized by both crystalline and amorphous regions. The energy gap calculated from UV-Vis data using the Kubelka-Munk method is 3.8eV. The constituents of N. nucifera fibre are identified to be carbon and oxygen through Energy Dispersive X-ray Spectroscopy (EDS) analysis.

Synthesis and Morphology of Slag-based Alkali-Activated Materials

AbstractThe present study focuses on the optimization of alkali activation of ferronickel (FeNi) slag for the production of alkali-activated materials (AAMs). The effect of the main factors including molarity and SiO2/Na2O molar ratio in the activating solution, pre-curing and curing time, curing temperature, and aging period on the compressive strength and other properties of the final products is assessed. Emphasis is paid to the study of the effect of low curing temperature to decrease the overall footprint of alkali activation. Several analytical techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM) are used for the identification of the mineralogy and the morphology of the precursor and the final products. The experimental results indicate that the produced AAMs achieve a maximum compressive strength of 99 MPa using NaOH molarity 8 mol/L (M), SiO2/Na2O molar ratio 1, curing temperature 80 °C, curing time 24 h, and aging period 7 days. SEM/EDS–energy dispersive X-ray spectroscopy analysis indicates that alkali activation results in a homogeneous binding phase, characteristic of the expected iron-rich matrix, while the microstructure of the AAMs is characterized by a glassy and smooth surface without the presence of any visible cracks or defects. The produced AAMs may be used as alternative binders for the replacement of cement in the production of concrete or as construction elements.

Excellent catalytic performance over reduced graphene-boosted novel nanoparticles for oxidative desulfurization of fuel oil

Abstract Three new inorganic–organic hybrid nanocomposites (In–WO3@rGO, Mo–WO3@rGO, and Mn–WO4@rGO) were synthesized by hydrothermal method and applied for recoverable and efficacious ODS process of real oil. The physicochemical analysis of novel nanocatalysts was conducted by various techniques, i.e., powder X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and thermogravimetric analysis. XRD and SEM analyses depicted that the nanoparticles (In–WO3, Mn–WO4, and Mo–WO3) were well embellished on the exterior of reduced GO with an amazing morphology, having a crystallite size of less than 40 nm. The catalytic activity of nanocomposites was scrutinized for real fuel (diesel and kerosene) and model fuel (DBT) using the radical initiator mechanism of the ODS pathway. Excellent efficiency can be obtained under optimized conditions using 0.1 g catalyst, 1 mL oxidant (H2O2), and100 ppm DBT at 40°C with a time duration of 180 min. Various factors such as time, DBT concentration, catalyst amount, oxidant amount, and temperature that affect catalytic activity directly or indirectly were also studied. A pseudo-first-order kinetics model was followed, and due to spontaneous reaction, a negative value of ΔG was observed with an activation energy of 6.54 kJ/mol for Mo–WO3@rGO, which is lower than that of the other two hybrids. The synthesized nanohybrids showed remarkable durability and recovery up to five times for the ODS process without significant change in proficiency.

Ecofriendly synthesis of NiZnFe2O5 nanoparticle by papaya leaf extract for electrochemical detection of ascorbic acid in orange juice and pharmaceuticals

A green technique has been employed to synthesize the NiZnFe2O5 nanoparticles using papaya leaf extract. The X-ray diffraction investigated the structural characteristics and crystalline size. The morphology of the synthesised nanoparticle is analysed by scanning electron microscopy. The average diameter of the nanoparticle is 47.93 nm, which was determined using the dynamic light scattering method. UV/Vis diffuse reflectance spectrum results revealed that the NiZnFe2O5 NPs band gap is 1.8 eV. It was calculated using the Kubelka-Monk function and energy dispersion X-ray spectroscopy analysis was used to identify the synthesized nanoparticle's elements. The electrochemical behaviour of NiZnFe2O5 modified glassy carbon electrode (GCE) nd bare GCE was studied to detect ascorbic acid using cyclic voltammetry and differential pulse voltammetry. Compared to unmodified GCE, NiZnFe2O5 nanoparticles modified GCE exhibit excellent electrocatalytic activity towards the AA oxidation, which was proved by the increase in peak current and decrease in peak potential. Electrochemical impedance analysis suggests that the NiZnFe2O5 nanoparticles significantly enhance the charge transfer rate. The linear response of the peak current on the concentration of AA was obtained in the range of 0.2-50 µM. The detection limit was found to be 1.038 µM. The present work serves as a systematic benchmark to assess the electrochemical sensing potential of NiZnFe2O5 NPs towards AA in orange juice and pharmaceuticals.

Miscibility, thermal, and mechanical properties of recycled waste tire rubber-modified polystyrene sustainable composites

Waste tires represent an important source of polymer waste. The ground tire rubber derived from waste tires is a recycled product that can be combined with polystyrene (PS) to produce high-performance PS and waste rubber composites. To improve composite material performance, surface grafting modification of waste tire rubber with styrene to enhance properties of PS composites as a novel approach was investigated. The surface morphology and structure of polystyrene grafted waste tire rubber powder via a conventional free radical polymerization were confirmed successfully using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy analyses in addition to the Fourier-transform infrared spectroscopy (FTIR). The comparative mechanical and thermal property analysis of PS sustainable composites with recycling waste tire rubber powder with and without surface grafting modifications indicated an approximate 4-fold increase in the impact strength of polystyrene grafted waste tire rubber reinforced PS sustainable composites in addition to enhanced interfacial miscibility. The development of sustainable composite materials from recycled waste tire provides a novel avenue to achieve close-loop polymer recycling, which is of significance in the development of the circular economy and an environmentally friendly society.

Lethal and Sublethal Toxicity of Nanosilver and Carbon Nanotube Composites to Hydra vulgaris-A Toxicogenomic Approach.

The increasing use of nanocomposites has raised concerns about the potential environmental impacts, which are less understood than those observed with individual nanomaterials. The purpose of this study was to investigate the toxicity of nanosilver carbon-walled nanotube (AgNP-CWNT) composites in Hydra vulgaris. The lethal and sublethal toxicity was determined based on the characteristic morphological changes (retraction/loss of tentacles and body disintegration) for this organism. In addition, a gene expression array was optimized for gene expression analysis for oxidative stress (superoxide dismutase, catalase), regeneration and growth (serum response factor), protein synthesis, oxidized DNA repair, neural activity (dopamine decarboxylase), and the proteasome/autophagy pathways. The hydras were exposed for 96 h to increasing concentrations of single AgNPs, CWNTs, and to 10% AgNPs-90% CWNTs, and 50% AgNPs-50% CNWT composites. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed the presence of AgNPs attached to the carbon nanotubes and AgNP aggregates. The data revealed that the AgNP-CWNT composites were more toxic than their counterparts (AgNPs and CNWT). The sublethal morphological changes (EC50) were strongly associated with oxidative stress and protein synthesis while lethal morphological changes (LC50) encompassed changes in dopamine activity, regeneration, and proteasome/autophagic pathways. In conclusion, the toxicity of AgNP-CWNT composites presents a different pattern in gene expression, and at lower threshold concentrations than those obtained for AgNPs or CWNTs alone.

Mn oxide-modified biochars with high adsorption capacity for Pb(II) in wastewater: Preparation and adsorption mechanisms.

The occurrence of excessive levels of bivalent plumbum (Pb(II)) in wastewater poses a notable threat to both human health and ecological safety. In this study, orthogonal experiments were conducted to prepare coprecipitation-modified biochar (C-BC) and impregnation pyrolysis-modified biochar (I-BC) via potassium permanganate (KMnO4) for removing Pb(II) from wastewater. Three types of modified biochars (BCs) (Mn-BCs) namely, C-BC400, I-BC400, and I-BC700, were selected as high-efficiency adsorbents on the basis of their high removal rates (87.2%, 88.0%, and 91.2%, respectively) for 400mg/L Pb(II) solutions. The transmission electron microscopy (TEM) and scanning electron microscopy (SEM)‒energy-dispersive X-ray spectroscopy (EDS) analysis results indicated that Mn elements were distributed only on the outer surfaces of the C-BC400 particles but occurred on the outer surface and were stably embedded in the I-BC400 and I-BC700 particles. Compared with those of the pristine (BCs), the Pb(II) adsorption rates of C-BC400, I-BC400, and I-BC700 increased by factors of 3.75, 2.09, and 5.70, respectively. The Pb(II) adsorption capacities of C-BC400, I-BC400, and I-BC700 (182.28, 133.16, and 69.25mg/g, respectively) were significantly greater than those of the pristine BCs produced at 400°C (45.43mg/g) and 700°C (40.71mg/g). The excellent adsorption ability of Mn-BCs for Pb(II) depends on various adsorption mechanisms, including complexation, electrostatic attraction, surface adsorption, and ion exchange. These results suggest that Mn-BCs exhibit high application potential in the remediation of Pb(II)-contaminated wastewater.

Hybrid magnetic nanocomposite NiFe2O4/TiO2 for Photocatalytic dye degradation and green hydrogen (H2) generation

The present paper focuses on designing and developing nanocomposites to modify their properties to increase the ability to generate hydrogen and degrade photocatalytic dyes. A nanocomposite of nickel ferrite (NiFe2O4)/Titanium dioxide (TiO2) was formulated using the sol-gel self-ignition method. X-ray diffraction (XRD) tool was adopted to analyze the structural behavior of pure nickel ferrite (NiFe2O4), pure titanium dioxide (TiO2), and nanocomposite of NiFe2O4/TiO2. XRD pattern of NiFe2O4 and TiO2 shows a monophasic nature whereas the XRD pattern of nanocomposites shows mixed phases of NiFe2O4 and TiO2. FTIR spectra confirm the formation of NiFe2O4, TiO2, and their composites with absorption bands near 400 cm-1 and 600 cm-1, 1500 cm-1. Raman spectra unveiled the presence of five active Raman modes in the case of NiFe2O4 whereas three active Raman modes are seen in TiO2. Field emission scanning electron microscopy (FE-SEM) images exposed the dense structure with spherical cluster-like morphology in the case of NiFe2O4. Energy-dispersive X-ray spectroscopy (EDX) analysis confirms the presence of all the desired elements of NiFe2O4, TiO2, and their composites in stoichiometric proportions. BET analysis of nickel ferrite NPs suggests a large surface area of the order of 31.54 m2/gm in comparison with TiO2 (19.23 m2/gm). The optical characterization was made through the UV-visible spectroscopic technique. TiO2 shows a maximum band gap of the order of 3.02 eV while NiFe2O4 shows a low band gap of the order of 1.74 eV. A typical M-H curve with saturation magnetization of the order of 27.54 emu/gm was observed for pure NiFe2O4. No magnetic properties were observed for TiO2 as it is a semiconductor. Enhancement in magnetic properties is observed with increases in NiFe2O4 content in a composite of NiFe2O4/TiO2. The photocatalytic activities were examined by degrading Methylene Blue (MB) dye under sunlight for pure nickel ferrite (NiFe2O4), pure titanium dioxide (TiO2), and a nanocomposite of NiFe2O4/TiO2. Photocatalytic hydrogen production reactions were carried out in a methanol/water solution under visible light. Consequently, the best configuration of the photocatalyst was determined as 25% wt% NiFe2O4/ TiO2 which had shown the maximum hydrogen (H2) production rate as 146.3 μmol/g/h after 8 h owing to its reduced bandgap energy and delayed e- / h+ recombination.