Energy Dispersive Spectral Analysis Research Articles

Purity and properties of spherical shaped Co3O4 nanocrystals prepared by a polyol route using a domestic microwave oven

Obtaining spherical shaped Co3O4 nanocrystals/nanoparticles (considered to be a very promising functional material) at low-cost with chemical purity, reduced crystallite size and useful physicochemical properties has been considered to be challenging. The present work (an attempt in this direction) involves the preparation of spherical shaped Co3O4 nanocrystals from cobalt acetate (dissolved in ethylene glycol) by a polyol synthesis route using a domestic microwave oven along with calcination at a suitable temperature (100/200/300/400 °C used to understand the phase evolution). X-ray diffraction (XRD, including Rietveld), infrared spectral, Raman spectral, energy dispersive X-ray absorption spectral and electron microscopic (SEM/TEM, including SAED) analyses have shown good crystallinity, chemical phase purity, spherical shape, reduced crystallite/particle size and narrow size distribution for the Co3O4 nanocrystal sample calcined at 400 °C. UV-Vis-NIR spectral analysis has shown the existence of multiple bandgap energies (1.51–1.98, 2.44–2.61 and 2.81–3.43 eV). Magnetic measurements have confirmed the antiferromagnetic nature possessing considerable magnetization below and above Neel temperature (TN), which indicates the presence of weak ferromagnetic ordering. The crystallite/particle sizes obtained for the sample calcined at 400 °C through XRD analysis, TEM analysis and using TN value (37.3 K) are 32.0, 33.6 and 31.3 nm, respectively. The method of preparation used is highly yielding, low-cost and more advantageous than many other methods used in the past.

Investigating the Effectiveness of Plant-Mediated Cerium Oxide Nanoparticles as Larvicidal Agents against the Dengue Vector Aedes aegypti

Aedes aegypti mosquito is responsible for the transmission of some of the most serious vector-borne diseases affecting humans, including dengue fever, chikungunya, and Zika. The only effective method for minimizing their transmission is vector control. In this work, an environmentally friendly method for synthesizing cerium oxide nanoparticles (CeO2 NPs) is highlighted, and the larvicidal activity against Ae. aegypti was studied. This method uses the aqueous extract of Bruguiera cylindrica leaves (BL) as an oxidizer and stabilizing agent. UV–Vis spectroscopy presented a distinctive absorbance band at 303 nm for CeO2 NPs with a band gap of 3.17 eV. The functional groups from the plant extract connected to CeO2 NPs were identified by FT-IR analysis, while X-ray diffraction revealed the cubic fluorite orientation of CeO2 NPs. Zeta potential revealed a surface charge of −20.7 mV on NPs. The formation of CeO2 NPs was confirmed by an energy dispersive spectral analysis, and TEM and DLS revealed an average diameter of 40–60 nm. The LC50 of synthesized CeO2 against Ae. aegypti fourth instar larvae was reported to be 46.28 μg/mL in 24 h. Acetylcholinesterase (47%) and glutathione S-transferase (13.51%) activity were significantly decreased in Ae. aegypti larvae exposed to synthesized CeO2 NPs versus the control larvae. All these findings propose the potential for using B. cylindrica leaves-synthesized CeO2 NPs as an efficient substitute for insecticides in the management of mosquitoes.

Combinatorial Synthesis of AlTiN Thin Films

Nitrides of aluminum (Al) and titanium (Ti) mixtures have long been studied and used as commercial coatings because of their high hardness and high oxidation resistance due to the formation of an alumina layer on the coating surface. To fully understand the contribution of Al and Ti to the properties of the film, a combinatorial deposition approach was employed using half-disk targets. Film growth was carried out using a magnetron sputtering system powered by a 13.56 MHz radio frequency power supply with varying argon (Ar) and nitrogen (N2) gas ratios. Depending on the location of the substrate relative to the target, atomic percent gradients of 0.60–0.70 Al and 0.30–0.40 Ti across the substrate surface were obtained from energy dispersive X-ray spectral analysis. X-ray diffraction peaks at 43.59°, 74.71° (face-centered cubic), and 50.60° (wurtzite) confirmed the presence of aluminum titanium nitride (AlTiN) mixtures, with an increasing amount of wurtzite phase at higher Al concentrations. For all samples, cauliflower-like nanograins were obtained and samples of the 80:20 Ar:N2 gas pressure ratio showed the smallest grain size among the three gas ratio combinations. The 80:20 Ar:N2 films revealed a relatively high hardness compared to the other gas ratios. All thin films exhibited good adhesion to 304 stainless steel substrates.

Synthesis and luminescent properties of red-emitting Li2CaSnO4: xEu3+ phosphors

Abstract Red emitting Li2CaSnO4: xEu3+ phosphors were successfully synthesized by the high-temperature solid-state method. The crystal structure, composite and luminescence properties (e.g. the excitation and emission spectra, fluorescent lifetimes, and CIE chromaticity coordinates) of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), energy dispersive spectrometer (EDS) and spectral analysis technique. The emission spectra consist of the characteristic peak resultant to Eu3+ under the excitation of 395 nm and the dominant emission peak is at 621 nm (7F0→5L6). The optimal red emission was obtained through 4% Eu3+ doping. These new red Li2CaSnO4: Eu3+ phosphors have the potential application for white LEDs.

Structural, morphological and optoelectronic aspects of YAlO3:Dy3+ doped nanocrystalline materials for NUV energized WLEDs

Cost-effective urea assisted solution combustion (SC) synthetic method was employed to prepare a series of doped YAlO3:xDy3+ (0.01–0.08 mol) phosphors. The resulting powdered samples were comprehensively examined through various structural as well as optical measurements. Rietveld refinement studies concluded that prepared nanomaterials structured into the orthorhombic system having Pbnm (62) space group. Energy dispersive spectral (EDS) analysis was executed to observe the relative proportions of constituent elements in all doped nanophosphors. Transmission electron microscopy (TEM) micrograph indicated the presence of agglomerated particles with the average size in the nano range. Photoluminescence excitation (PLE) spectra showed that the designated phosphors could be excited by near ultraviolet (NUV) energized lighting sources. The strongest emission centred at 576 nm, corresponding to electric dipole (4F9/2 → 6H13/2) transition of Dy(III) ion. Furthermore, characteristics photometric parameters viz. correlated color temperature (CCT), chromaticity coordinates (x and y), and color purity (%) were figure out with the aid of PL data, which strongly endorsed their usage in NUV energized WLEDs applications.

Effect of Neodymium substitution on the structural, morphological and optical properties of yttrium oxide nanocrystals

ABSTRACT Pure and neodymium (Nd) substituted yttrium oxide nanoparticles were synthesized by the co-precipitation technique. The synthesized materials were annealed at 350°C, 500° C, 750° C and 1000° C using a muffle furnace at an open atmosphere. X-ray diffraction patterns, FTIR spectra and XPS spectra were recorded to study the structural variations. The morphology has been studied through high-resolution SEM images. The elemental analysis was carried out using energy-dispersive spectral analysis by X-rays. The particle sizes and crystalline nature of the annealed samples were studied by transmission electron microscopic images and their corresponding SAED patterns. The photoluminescence spectral analysis indicated that the pure, as well as Nd-substituted materials have emissions in the blue and green regions. It is also observed that the substitution of Nd has enhanced the emission in the blue region. Moreover, the photoluminescence of Nd-substituted Yttrium oxide has a significant variation with respect to annealing temperatures.

SYNTHESIS, STRUCTURAL, OPTICAL, MAGNETIC AND PHOTOCATALYTIC ACTIVITY OF NICKEL DOPED ZnO NANOPARTICLES

In the current research, we have synthesized Ni doped zinc oxide nanoparticles by solvothermal method at four different ratios (X = 2%, 4%, 6% and 8%). The samples were characterized for structural analysis by X-ray diffraction, morphological analysis by Field Emission Scanning Electron Microscope, elemental composition by Energy Dispersive Spectral Analysis, optical properties by UV Visible absorption studies, photoluminescence studies, Fourier Transform Infrared Analysis, Magnetic properties by Vibrating Sample Magnetometer of (x=2%). As a application of this work all the samples were subjected to test for the degradation of Rhodamine 6G dye under visible light and exhibited a better photocatalytic activity.

The Effects of Electron Beam Irradiation on the Morphological and Physicochemical Properties of Magnesium-Doped Hydroxyapatite/Chitosan Composite Coatings.

This work reports on the influence of 5 MeV electron beam radiations on the morphological features and chemical structure of magnesium-doped hydroxyapatite/chitosan composite coatings generated by the magnetron sputtering technique. The exposure to ionizing radiation in a linear electron accelerator dedicated to medical use has been performed in a controllable manner by delivering up to 50 Gy radiation dose in fractions of 2 Gy radiation dose per 40 s. After the irradiation with electron beams, the surface of layers became nano-size structured. The partial detachment of irradiated layers from the substrates has been revealed only after visualizing their cross sections by scanning electron microscopy. The energy dispersive X-ray spectral analysis of layer cross-sections indicated that the distribution of chemical elements in the samples depends on the radiation dose. The X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction analysis have shown that the physicochemical processes induced by the ionizing radiation in the magnesium doped hydroxyapatite/chitosan composite coatings do not alter the apatite structure, and Mg remains bonded with the phosphate groups.

Cuprous delafossites, Cu3(MFeSb)O6 (M = Na, Li) with honeycomb arrays, realized by topochemical ion-exchange reactions

The current work describes the synthesis, structure, magnetic and optical properties of Cu1+ based delafossite oxides, Cu3(MFeSb)O6 (M = Na, Li) synthesized by the topotactic ion-exchange reactions (around 400 °C) of CuCl with Na4FeSbO6 and Na3LiFeSbO6 in an inert argon atmosphere. The synthetic procedure is significant as the oxides could not be synthesized by the solid state methods. Chemical analysis coupled with energy dispersive spectral analysis confirmed the extent of replacement of Na+ ions by Cu+ ions. A complete exchange of alkali metal ion, Na+ by Cu1+ in the interlayers of these honeycomb oxides has been achieved using a ratio of 1:3 between Na4FeSbO6 and CuCl. An additional exchange of approximately 70 % Na+ ions from the honeycomb arrays is possible by varying the ratio to 1:4. Rietveld refinements (space group C2/c) of the powder X-ray diffraction data have been carried out to ascertain the phase purity and to verify the structure formed by edge shared honeycomb arrays separated by Cu1+ in dumbbell configuration (O–Cu1+-O). X-ray photoelectron spectroscopy analysis confirmed the oxidation states of the constituent ions, specifically copper as Cu1+. A similar method is adopted to synthesize Cu3(LiFeSb)O6 by reacting Na3(LiFeSb)O6 and CuCl in the ratio 1:3 at 400 °C. These new delafossite oxides, Cu3(MFeSb)O6 (M = Na, Li) and Cu3((Cu0.7Na0.3)FeSb)O6, exhibit interesting magnetic properties which are significantly different from the rock salt based parent sodium analogs. Dominant antiferromagnetic interactions with a specific ordering temperature have been observed for these samples containing Fe3+ (d5) ions in the honeycomb. UV–visible diffuse reflectance measurements indicated the decrease in the band gap of Cu1+ based oxides. This study highlights the importance of low temperature ion-exchange reactions as an effective route to stabilize multifunctional materials of potential importance for various applications.

The identification of the true nature of pseudofungus structures as polyurethane catheter fragments

Pseudofungus structures in lymph node tissues have been reported on multiple occasions. Despite a variety of investigative tests including histochemical special stains and energy dispersive spectral analysis, the underlying nature and origin of these pseudofungus structures has never been clearly defined. The most common hypothesis suggests that they represent collagen fibers that become coated with iron and calcium. Herein, evidence is given that the pseudofungus structures identified in the lymph node tissues represent fragments of polyurethane catheters. The evidence includes both a comparison of these pseudofungus structures to fragments of polyurethane well documented in the literature and a comparison of polyurethane catheter scrapings to the pseudofungus structures identified in the literature. In both of these comparisons, the morphology of the polyurethane fragments are identical to the pseudofungus structures. This is the first definitive report identifying polyurethane catheter fragments as representing the true nature and etiology of pseudofungus structures in lymph node tissues.

Biosynthesis of spherical selenium nanoparticles with halophilic Bacillus subtilis subspecies stercoris strain XP for inhibition of strawberry pathogens

Biosynthesis of nanomaterials has attracted much attention for its excellent characteristics such as low energy consumption, high safety, and environmental friendliness. As we all know, the toxic selenite can be transformed into higher-value nanomaterials by using bacteria. In this study, nano-selenium was synthesized by halophilic Bacillus subtilis subspecies stercoris strain XP in LB medium supplemented with selenite (electron acceptor). The physicochemical characteristics of nano-selenium were analyzed by scanning electron microscope (SEM), X-ray energy dispersive spectral analysis (EDAX), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). Meanwhile, the antifungal activity of nano-selenium to strawberry pathogens (fusarium wilt, erythema, and purple spot fungi) was determined. The products from reduction of selenite by strain XP was amorphous spherical selenium nanoparticles (SeNPs) with a diameter range of 135-165 nm. The production of SeNPs was positively correlated with time (0-48 h) and no changes were observed on cell morphology. Selenium was dominant in the surface of SeNPs where the organic elements (C, O, N, and S) existed at the same time. SeNPs were coated with biomolecules containing functional groups (such as -OH, C=O, N-H, and C-H) which were associated with the stability and bioactivity of particles. Although the highest concentration of SeNPs had significant (P<0.05) inhibitory effects on three strains of strawberry pathogens, antifungal activity to erythema and fusarium wilt pathogenic fungi was higher than that to purple spot pathogenic fungi from strawberry. In conclusion, strain XP not only has strong tolerance to high salt stress, but can be also used to synthesize biological SeNPs with good stability and biological activity. Thus, the strain XP has bright perspectives and great potential advantage in pathogens control and green selenium-rich strawberry planting as well as other fields.

A novel blue-emitting phosphors (CsBaYB6O12:Ce3+): Potential applications in w-LEDs and X-ray phosphors

We have synthesized powder samples of pure and Ce3+ doped cesium barium yttrium hexaborate (CsBaYB6O12) using a standard solid-state reaction technique. The prepared samples were characterized by different techniques. Powder X-ray diffraction (PXRD) was used to identify the phase purity of the prepared phosphors. The field emission scanning electron microscopy (FE-SEM) technique was used to examine the size and shape of the synthesized powder samples. The energy-dispersive spectral analysis (EDS) was used to identify the elements present in the synthesized compounds. X-ray-induced luminescence spectra, photoluminescence (PL), and thermoluminescence (TL) analysis were used to investigate the luminescence properties of the prepared compound. The rare earth ion of Ce3+ improves the intrinsic luminescence of CsBaYB6O12 and 4 mol% was found to be the optimal concentration. The dopants found to have two different excitation PL bands at 340 nm and 360 nm which yields the same emission bands of 385 and 417 nm which are well-matched with that found in the X-ray emission bands. The kinetic parameters of the measured experimental TL glow curve has been studied by various standard methods such as deconvolution, Variable heating rate and initial rise method. In this manuscript we report the luminescence properties of the prepared phosphors in a detailed manner for the first time.

Multifunctional Oil Absorption with Macroporous Polystyrene Fibers Incorporating Silver-Doped ZnO

Hydrophobic microporous polystyrene (PS) fibers are fabricated by a solvent-induced phase-separation-assisted electrospinning method. Zinc oxide (ZnO) and silver-doped zinc oxide (Ag-ZnO) nanomaterials with variable morphologies are added to the PS fibers, to investigate the influence of multifunctional nanofiller addition on the porosity and consequent oil-adsorbing properties for different oil types. The doping of silver as well as the uniformity in particle distribution are confirmed by scanning electron microscopy and the energy-dispersive spectral analyses. The porosity of the fibers and their crystallinity effect depend on the hydrophobicity and surface properties of these microporous nanofilled fibers. Ag-ZnO, specifically in 2 wt %, enhanced the pore size and distribution in PS porous fibers, thereby enhancing the oil-adsorbing property and its hydrophobicity. In-depth analysis of the oil adsorption mechanism is done for the fibers, both qualitatively and quantitatively, to demonstrate its correlation with the structural integrity of the fibers. The PS/2Ag-ZnO composite also exhibits the highest antibacterial performance against Staphylococcus aureus, a general indication of antibiological fouling properties of these oil-separating films. The antifouling/antibacterial activity of the nanoparticles and high oil sorption capacity of the highly porous PS composites show great potential for use in water-treatment-related applications.

Adsorption of 2,4-Dichlorophenol and Phenol from Aqueous Solutions by Silicate Sorbent

The adsorption of phenol and 2,4-dichlorophenol by diatomite sorbent SMD-Sorb from aqueous solutions is studied. Scanning electron microscopy and energy dispersive X-ray spectral analyses are performed to determine the surface morphology and elemental composition of SMD Sorb diatomite. The specific surface area and total pore volume of the adsorbent are measured via the dynamic low-temperature adsorption of liquid nitrogen. The values of sorption capacity (for phenol and 2,4-dichlorophenol), bulk density, moisture content, and water absorption are estimated. It is shown that the sorbent has fairly low adsorption capacity with respect to the considered substances. The parameters of adsorption equilibria in the surface layers of the studied sorbent are calculated: i.e., the distribution coefficient, limiting adsorption, Henry constants, change in Gibbs energy, adsorption coefficient, and degree of filling, depending on temperature.

To question about Fe5B3 boride formation in boron-rich Fe–В alloys

The structure of boron-rich iron alloys in the concentration range of 9.0–15.0 wt. % В, 0.01–0.17 wt. % C, Fe – the balance (with charge impurities of Si, Al, Mn) was investigated in this work. The methods of metallographic, X-ray, stop-quenching, scanning electron microscopic, energy dispersive, and fluorescent spectral analyses were applied. The FeB- and Fe2B-based solid solutions are proved to be the major constituents of the investigated alloys. No evidence is found for the possible formation of the Fe5B3 boride via peritectic reaction L+FeB→Fe5B3 at 1650 K and its further decomposition via eutectoid reaction Fe5B3→FeB+Fe2B at 1410 K. It is shown that the phase under consideration is iron hemiboride alloyed mainly by silicon which peritectically forms from primary crystals of iron monoboride and the rest of liquid at 1650 K. The thermal effect at 1410 K is assumed to be caused by a heat production connected with polymorphic transformation α-FeB→β-FeB in the presence of carbon.

Role of the solvent medium in the wet-chemical synthesis of CuSbS2, Cu3SbS3, and bismuth substituted Cu3SbS3

Co-thermal decompositions of equimolar concentrations of thiourea complexes ([Cu(tu)3]Cl and [Sb(tu)2]Cl3) in ethylene glycol and ethanolamine were attempted. Based on the results from powder X-ray diffraction, Raman spectroscopy, and energy dispersive spectral analysis of the products, Cu3SbS3 in cubic symmetry emerged from ethylene glycol. In contrast, orthorhombic CuSbS2 resulted from the ethanolamine medium. The generation of copper-rich and copper-poor sulfides was found to be the major reason behind the formation of these stoichiometries of the Cu-Sb-S system as verified by reacting the preformed Cu-S and Sb-S species in ethanolamine and ethylene glycol. Attempts to include bismuth (up to 50 mol%) for antimony were successful only in ethylene glycol medium. The inclusion of bismuth stabilized the orthorhombic form of Cu3SbS3, possibly due to the non-bonded lone pairs present on Bi3+ and Sb3+-ions. The inclusion of bismuth confirmed from the successful refinement of powder X-ray diffraction pattern by the Rietveld method, Raman spectroscopy, and energy dispersive spectroscopy analysis. CuSbS2, Cu3SbS3 (cubic) and Cu3Sb0.50Bi0.50S3 showed broad absorption extending up to visible region in their UV-visible spectra. The bandgap values of 1.31, 1.40 and 0.94 eV were estimated by Tauc plots for Cu3SbS3, CuSbS2, and Cu3Sb0.50Bi0.50S3, respectively. CuSbS2, Cu3SbS3 (cubic) and Cu3Sb0.50Bi0.50S3 showed broad absorption extending up to visible region in their UV-visible spectra. The bandgap values of 1.31, 1.40 and 0.94 eV were estimated by Tauc plots for Cu3SbS3, CuSbS2, and Cu3Sb0.50Bi0.50S3, respectively.

Use of energy dispersive X-ray spectral analysis in a scanning electron microscope system to evaluate the mineral composition of grain bread

The concentration of 18 basic elements (in% by weight) contained in the morphological parts of wheat, rye and triticale grains was studied. It is established that the nature of the distribution of micronutrients is determined by their biological role. The elements are part of enzymes: manganese, iron and zinc prevail in the nucleus. Phosphorus, potassium, magnesium are found in greater quantity in the vital layer of aleurone. Cobalt, nickel, aluminum, calcium, chromium, copper, selenium and cadmium dominate the grain surface. The largest amount of mineral elements in the grain is concentrated in the seed. The distribution of metals in triticale grains is characterized by characteristic patterns of wheat and rye. In the distribution of mineral elements in wheat, rye and triticale grains, differences are observed, which are explained by the specific characteristics of these plants. From the grain studied, cereal bread was prepared unmatched on a thick grain leaven. The analysis of the mineral content of the grain bread showed that it was enriched with all major biogenic mineral elements and contained toxic metals (lead and cadmium) in a quantity not exceeding the CMP. A strong negative correlation has been established between levels of certain biological and toxic elements in grain and in pain. The revealed relationship indicates the possibility of switching from dispersive X-ray spectroscopy in a scanning electron microscope system to predict the quality and safety of grain pain, particularly for predicting of the content heavy metals in finished bakery products.

Non-toxic nano approach for wastewater treatment using Chlorella vulgaris exopolysaccharides immobilized in iron-magnetic nanoparticles

The current study, novel magnetic nano-composite particles (Fe3O4@EPS) were successfully synthesized via the co-precipitation of iron (III) chloride and iron (II) sulfate (Fe3O4 nanoparticles) with exopolysaccharides (EPS) derived from the microalga Chlorella vulgaris. The physico-chemical nature of the Fe3O4@EPS was investigated in depth. Transmission electron microscopy (TEM) results estimated the core-shell nature of Fe3O4@EPS aggregated inside the indistinctly layered EPS matrix to be 10–20 nm in size. Scanning electron microscopy-based energy dispersive spectral analysis indicated that elemental Fe was successfully loaded on to the EPS polymeric ion-exchanger at a rate of 63.3% by weight. FT-IR results demonstrated that Fe3O4 nanoparticles were successfully modified by the functional groups present in EPS. Fe3O4@EPS showed a highly magnetic nature at 5.0 emu/g. The XPS survey spectrum, which showed two major peaks at 724.1 and 710.2 eV revealed the elemental composition and electronic structure of Fe3O4 nanoparticles and Fe3O4@EPS. Furthermore, nutrient removal from wastewater was studied. Under optimum conditions (3.5 g/L of Fe3O4@EPS, pH 7.0 and 13 h of incubation) 91% of PO43− and 85% of NH4+were effectively eliminated. These findings demonstrate the potential of Fe3O4@EPS for removing PO43− and NH4+ in wastewater treatment plants.

Micro hole fabrication in TiN-Al2O3 ceramic composite by SiC powder assisted micro- EDM

Considering the importance of ceramics in many microdevice applications, a modified micro-electrodischarge process in which the addition of silicon carbide powders in the dielectric was used to fabricate high aspect ratio microholes in dense and hard TiN-Al2O3 ceramic composite has been described in the present paper. TiN-Al2O3 ceramics has been prepared by reactive hot pressing technique. Response Surface Methodology (RSM) has been employed to design and optimize the experimental input parameters like voltage, capacitance, and tool rotation speed and for evaluating the responses in terms of Material Removal Rate (MRR), Electrode Wear Rate (EWR), Radial Overcut (ROC) and Taper Angle (TA). SiC powder addition has shown the improvement in MRR by 6.5 times, reduction of TA by 2 times and reduction in ROC by 1.5 times. However, EWR has increased by 1.8 times. Improvement in the machining performance has been analysed with respect to the early breakdown of the dielectric fluid by the addition of SiC powder and the enlargement of the discharge gap. Topographies of the machined surfaces analysed from the Scanning Electron Micrographs (SEM) show smoothening of the surface by SiC powder addition and reduction of tool rotation speed. Chemical compositions of the machined surfaces determined by energy dispersive spectral analysis (EDS) showed the formation of amorphous Ti-Al-O-N phase by the discharge. Thermal micro-cracking of the amorphous solidified melt, spalling, micro-bubble formation and accumulation of spherical electrode debris have been observed during the machining of TiN-Al2O3 ceramic-composite.

Synthesis, characterization and photocatalytic dye degradation capability of Calliandra haematocephala-mediated zinc oxide nanoflowers

An environmentally sound approach towards the green synthesis of zinc oxide nanostructures has been achieved with an aqueous extract of Calliandra haematocephala leaves. The nanoparticles were characterized using various analytical techniques to substantiate the structural details. An absorption band at 358 nm corresponds to the formation of zinc oxide nanoparticles. Scanning electron microscopy revealed the nanoflower morphology of the nanoparticles. Energy dispersive spectral analysis portrayed the strong presence of zinc and oxygen, while X-ray diffraction showed the nanoparticles to conform to hexagonally-formed wurtzite structure. The crystallite size of the nanoflowers was estimated to be 19.45 nm. Vibrational frequencies, typical of zinc‑oxygen and other functional groups, were revealed using Fourier transform infrared spectroscopy. BET analysis revealed that the pores were of mesoporous nature with an estimated specific surface area of 9.18 m2/g. The photocatalytic nature of the nanoparticles was established by the degradation of methylene blue (MB) dye, under solar radiation. Up to 88% degradation was achieved in a duration of 270 min. Kinetic data from the studies proved that the reaction was compliant with first-order model, with rate constant as 0.01 min−1. The study illustrated the synthesis of zinc oxide nanoparticles using a novel source, viz., the leaves of C. haematocephala.