Sesamum indicum Plant Extracted Microwave Combustion Synthesis and Opto-Magnetic Properties of Spinel MnxCo₁₋xAl₂O₄Nano-Catalysts

Uptake and bioaccumulation of iron oxide nanoparticles (Fe3O4) in barley (Hordeum vulgare L.): effect of particle-size

Root-to-shoot translocation of nanoparticles (NPs) is a matter of interest due to their possible unprecedented effects on biota. Properties of NPs, such as structure, surface charge or coating, and size, determine their uptake by cells. This study investigates the size effect of iron oxide (Fe3O4) NPs on plant uptake, translocation, and physiology. For this purpose, Fe3O4 NPs having about 10 and 100 nm in average sizes (namely NP10 and NP100) were hydroponically subjected to barley (Hordeum vulgare L.) in different doses (50, 100, and 200 mg/L) at germination (5 days) and seedling (3 weeks) stages. Results revealed that particle size does not significantly influence the seedlings' growth but improves germination. The iron content in root and leaf tissues gradually increased with increasing NP10 and NP100 concentrations, revealing their root-to-shoot translocation. This result was confirmed by vibrating sample magnetometry analysis, where the magnetic signals increased with increasing NP doses. The translocation of NPs enhanced chlorophyll and carotenoid contents, suggesting their contribution to plant pigmentation. On the other hand, catalase activity and H2O2 production were higher in NP10-treated roots compared to NP100-treated ones. Besides, confocal microscopy revealed that NP10 leads to cell membrane damages. These findings showed that Fe3O4 NPs were efficiently taken up by the roots and transported to the leaves regardless of the size factor. However, small-sized Fe3O4 NPs may be more reactive due to their size properties and may cause cell stress and membrane damage. This study may help us better understand the size effect of NPs in nanoparticle-plant interaction.

Effect of Ce3+ Ions Doped NiFe₂O₄ Magnetic Nanoparticles on Photocatalytic Degradation of Rhodamine B and Antibacterial Activities

In this study, spinel NiCe_xFe_2-XO₄ (x = 0.0 - 0.5) nanoparticles (NPs) was synthesized by microwave combustion technique (MCT) utilizing the fuel of Aloe vera plant extract. The establishment of spinel cubic crystal structure was ensured by powder X-ray diffraction (PXRD) technique. The particles like nanostructured morphology were confirmed by high-resolution scanning electron microscope (HRSEM). Energy dispersive X-ray (EDX) studies confirmed the formation of spinel ferrite structure and ensured that no other elements were present. Magnetic parameters such as remanant magnetisation (Mr), coercivity (He) and saturation magnetization (Ms) were calculated from the magnetic hysteresis (M-H) loops, which exhibited ferromagnetic behaviour. The photocatalytic behavior was investigated by visible light treatment for the photocatalytic degradation (PCD) of rhodamine B (Rh-B) dye and the sample NiCe_0.3Fe_1.7O₄ exhibits higher PCD efficiency (93.88%) than other compositions. The antibacterial activities of gram-positive S. aureus, B. subtilis, gramnegative K. pneumonia and E. coli have been investigated using undoped and Ce³⁺ substituted NiFe₂O₄ NPs and observed higher activity, which indicated that, they can be used in the bio-medical applications.

Synthesis, characterization and photocatalytic application of Sophora mollis leaf extract mediated silver nanoparticles

This study reports green synthesis and characterization of silver nanoparticles (Ag NPs) from Sophora mollis leaf extract. The use of S. mollis extract for preparation of Ag NPs was investigated using different techniques. Dark brown color indicates formation of nanoparticles. Fourier transform infra-red (FTIR) analysis revealed that plant extract act as a reducing and capping agent. Morphological aspects of Ag NPs were ascertained by means of SEM studies. Energy dispersive and FTIR spectroscopy results showed chemical composition and plant extract functionality respectively. X-ray diffraction (XRD) analysis showed particle size of 70 nm. Antibacterial activity of NPs was investigated by disc diffusion and minimum inhibitory concentration method. Antioxidant activity of NPs was shown by DPPH assay. The photo catalytic efficiency of synthesized Ag NPs was evaluated by degradation of methylene blue (MB) dye under UV irradiation. Ag NPs degraded MB dye up to 88% in 160 min. It is concluded that these NPs could be employed for degradation of toxic industrial effluents. Result proved the green synthesis of Ag NPs from S. mollis extract is clean, economical and safe method.

Engineered magnetic nanoparticles enhance chlorophyll content and growth of barley through the induction of photosystem genes

This study investigates the impact of an engineered magnetic nanoparticle (MNP) on a crop plant. For this purpose, a sonochemical synthetic approach was utilized in order to dope magnetic elements (Co and Nd) into technologically important iron oxide NPs. After being characterized by using TEM, SEM, and XRD instruments, the MNPs were hydroponically applied to barley plants with varying doses (from 125 to 1000 mg/L) both in germination (4 days) and early growing stages (3 weeks). Physiological responses, as well as expression of photosystem marker genes, were assessed. Compared to the untreated control, MNP treatment enhanced germination rate (~ 31%), tissue growth (8% in roots, 16% in shoots), biomass (~ 21%), and chlorophyll (a, b) (~ 20%), and carotenoids (~ 22%) pigments. In general, plants showed the highest growth enhancement at 125 or 250 mg/L treatment. However, higher doses diminished the growth indices. Compared to the control, the catalase activity was significantly reduced in the leaves (~ 33%, p < 0.005) but stimulated in the roots (~ 46%, p < 0.005). All tested photosystem marker genes (BCA, psbA, and psaA) were overexpressed in MNP-treated leaves than non-treated control. Moreover, the gene expressions were found to be proportionally increased with increasing MNP doses, indicating a positive correlation between MNPs and the photosynthetic machinery, which could contribute to the enhancement of plant growth.

Structural, electric and dielectric properties of perovskite based nanoparticles for energy applications

A nanocomposite electrode, obtained by combining two high performance perovskite materials, such as lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) and gadolinium doped ceria, Ce0.85Gd0.15O1.5 (GDC), were investigated as a promising cathode for moderate temperature solid oxide fuel cells (SOFCs). The synthesized material has good conductivity and catalytic performance. The purpose of this synthesis was to prepare a stable and highly performing nanocomposite cathode material. In this research work, LSCF and GDC were separately synthesized by co-precipitation and solid-state reaction method to gain a homogeneous perovskite phase. Varying concentrations of LSCF–GDC composite with GDC (10 wt.%, 20 wt.% and 30 wt.%) were synthesized followed by calcination at 600 °C to remove water content and to achieve an adequate porous structure for oxygen absorption and desorption. These fabricated LSCF, GDC, and the nanocomposite specimens were characterized for microstructure, particle size etc. via. X-ray diffraction method (XRD), scanning electron microscope (SEM) and the laser particle size analyzer. This procedural approach helps to expand new methods for generating bi-functional duel nano-sized perovskites with great performance and stability which can be utilized for advancement of renewable energy sectors especially for rechargeable fuel batteries.

Structural, electric and dielectric properties of perovskite based nanoparticles for energy applications

A nanocomposite electrode, obtained by combining two high performance perovskite materials, such as lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) and gadolinium doped ceria, Ce0.85Gd0.15O1.5 (GDC), were investigated as a promising cathode for moderate temperature solid oxide fuel cells (SOFCs). The synthesized material has good conductivity and catalytic performance. The purpose of this synthesis was to prepare a stable and highly performing nanocomposite cathode material. In this research work, LSCF and GDC were separately synthesized by co-precipitation and solid-state reaction method to gain a homogeneous perovskite phase. Varying concentrations of LSCF–GDC composite with GDC (10 wt.%, 20 wt.% and 30 wt.%) were synthesized followed by calcination at 600 °C to remove water content and to achieve an adequate porous structure for oxygen absorption and desorption. These fabricated LSCF, GDC, and the nanocomposite specimens were characterized for microstructure, particle size etc. via. X-ray diffraction method (XRD), scanning electron microscope (SEM) and the laser particle size analyzer. This procedural approach helps to expand new methods for generating bi-functional duel nano-sized perovskites with great performance and stability which can be utilized for advancement of renewable energy sectors especially for rechargeable fuel batteries.

Structural, magnetic, optical properties and cation distribution of nanosized Ni0.3Cu0.3Zn0.4TmxFe2-xO4 (0.0 ≤ x ≤ 0.10) spinel ferrites synthesized by ultrasound irradiation

In this study, Tm³⁺ ion substituted NiCuZn nanospinel ferrites, Ni_0.3Cu_0.3Zn_0.4Tm_xFe_2-xO₄ (0.0 ≤ x ≤ 0.10), have been synthesized sonochemically. The structural, spectroscopic, morphological, optic and magnetic investigation of the samples were done by X-ray powder diffractometry (XRD), Fourier transform infrared spectrophotometry (FT-IR), UV-Vis diffused reflectance (%DR) spectrophotometry, transmission and scanning electron microscopies (TEM and SEM) along with EDX, Vibrating sample magnetometry (VSM), respectively. The purity of prepared products were confirmed via XRD, FT-IR, EDX and elemental mapping analyses. The analyses of magnetization versus M(H) (applied magnetic field) were performed at 300 and 10 K. The following magnetic parameters like M_s (saturation magnetization), SQR = M_r/M_s (squareness ratio), n_B(magnetic moment), H_c (coercivity) and M_r (remanence) have been discussed. M(H) loops revealed superparamagnetic property at RT and soft ferromagnetic nature at 10 K. It is showed that the Tm³⁺ substitutions significantly affect the magnetizations data. A decreasing trend in the M_s, H_c, M_r, and n_B values was detected with Tm³⁺ substitution.

Uptake and translocation of magnetite (Fe3O4) nanoparticles and its impact on photosynthetic genes in barley (Hordeum vulgare L.)

This study investigates the fate and impact of iron oxide or magnetite (Fe₃O₄, ∼13 nm in size) nanoparticles (NPs) in barley (Hordeum vulgare L.), a common crop cultivated around the world. Barley seedlings were grown in hydroponic culture for three weeks to include NPs (125, 250, 500, and 1000 mg/L). Transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) techniques were used to assess their uptake and translocation. Photosynthesis marker genes were quantified by RT-qPCR. Results revealed that increasing doses of Fe₃O₄ NPs were gradually enhanced the plant growth up to 500 mg/L, which promoted the fresh weight (FW) respectively ∼19% and ∼88% for leaf and root tissues than the ones for control. No phytotoxic effect was recorded even at high NPs doses. NPs inclusion increased some phenological parameters such as chlorophyll, total soluble protein, number of chloroplasts, and dry weight. High NPs doses dramatically reduced the catalase activity and hydrogen peroxide content, suggesting a possible function of NPs as nanozyme in vivo. TEM observations showed that Fe₃O₄ NPs penetrated and internalized in the root cells. In leaves, they were mostly existed at the surrounding cell wall, suggesting their translocation from root to shoot without cellular penetration. Further analysis by using VSM confirmed the existence of Fe₃O₄ NPs in leaves which result in dramatic alterations of the photosystem genes (PetA, psaA, BCA and psbA). In conclusion, barley plants uptake and translocate Fe₃O₄ NPs, which promoted the plant growth probably due to the promoted gene expression and efficient photosynthetic activity.

Sol–Gel Synthesis of Mesoporous Silica–Iron Composite: Kinetics, Equilibrium and Thermodynamics Studies for the Adsorption of Turquoise-Blue X-GB Dye

Mesoporous silica (MPS) and MPS-Fe composite was prepared via sol–gel technique and characterized by BET, FTIR, XRD, SEM and pZc. The MPS and MPS-Fe adsorption efficiencies were evaluated for a cationic dye Turquoise-blue X-GB. The MPS-Fe composite showed pore size and BET values of 9.52 nm and 309 m2/g, respectively. XRD and SEM analysis revealed the amorphous nature and uniform distribution of spherical partciles with average particle size of 50 nm of MPS-Fe composite. The points of zero (pZc) charge found to be 2.3 and 6.3 for MPS and MPS-Fe, respectively. The MPS and MPS-Fe showed promising efficiency for the adsorption of Turquoise-blue X-GB as a function of medium pH, contact time, dye initial concentration and temperature. Among, Freundlich, Langmuir, Harkins–Jura, Temkin, Doubinin–Radushkevich isotherms, the Turquoise-blue X-GB followed Langmuir isothermal model with adsorption capacities of 83.34 mg/g and 74.07 mg/g for MPS and MPS-Fe composite, respectively. Among kinetics models, pseudo second order kinetic model fitted to the dye adsorption with R2 values of 0.998 and 0.988 for MPS and MPS-Fe composite, respectively. The negative values of enthalpy (ΔH) and free energy (ΔG) revealed exothermic and spontaneous adsorption of dye at room temperature. Results revealed that MPS and MPS-Fe composite have promising potential for Turquoise-blue X-GB dye adsorption and could possibly be extended for the adsorption of dyes from textile effluents.

A Novel Approach for Fabricating LaMnO3 Thin Films Using Combined Microwave Combustion and Pulsed Electron Deposition Techniques

LaMnO3 (LMO) nanopowder was synthesized by the microwave combustion method using glycine and nitrate salts of La and Mn as precursors. The as-prepared LMO powder was pressed at high pressure and annealed at 1000°C for 8 hours to make a target for thin film deposition. The structural and elemental analysis was obtained by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Thin films of LMO were fabricated using pulsed electron deposition (PED) at room temperature. The effects of discharge voltage and oxygen/argon flux ratio on the produced thin films were studied. The study shows that stoichiometry and structure of the target was preserved well in the thin films prepared with a discharge voltage from 14 to 15 kV, while the oxygen/nitrogen flux ratio did not show a clear effect on the quality of thin films.

Structural, Dielectric and Magnetic Studies of Perovskite [Gd1−xMxCrO3 (M = La, Co, Bi)] Nanoparticles: Photocatalytic Degradation of Dyes

Nanoparticles (NPs) of Gd1−xMxCrO3 (M = La, Co, Bi) were synthesized by microemulsion techniques, involving simultaneous single ion substitution philosophy. Structural, magnetic, dielectric properties, morphology, elemental analysis and distribution size of fabricated nano-crystalline were determined. The techniques employed for investigation are X-ray diffraction (XRD), vibrating sample magnetometer (VSM), dielectric measurement and scanning electron microscopy (SEM), energy dispersive X-ray (EDX), photoluminescence (PL) and atomic force microscopy (AFM), respectively. XRD pattern confirm that all the as-synthesized NPs have orthorhombic structure and successfully substituted of different metal ions into the regular crystal structure of GdCrO3. The lattice parameters X-ray density, bulk density, porosity and grain size were calculated from XRD pattern of Gd1−xMxCrO3 (M = La, Co, Bi) substituted and un-substituted GdCrO3. The magnetic hysteresis loop of fabricated product confirmed that the entire sample exhibits ferromagnetic behavior at room temperature. It was also found that the fabricated NPs show excellent photocatalytic activity (PCA) against Congo-red, about 78.24% after 55 min of incubation.