Amount Of Ethylenediaminetetraacetic Acid Research Articles

The impact of varying EDTA dosage on the flower-like morphology and thermoelectric properties of Ce-doped Bi2Te₃

Thermoelectric materials have significant applications in energy utilization and environmental protection. The effect of different EDTA (ethylenediaminetetraacetic acid) dosages on the flower-like morphology and thermoelectric properties of Ce-doped Bi2Te3 nanoparticles were investigated. The Ce-doped Bi2Te3 nanoparticles were sucessfully prepared via the hydrothermal method, and the influence of EDTA dosage on the morphology, structure, and thermoelectric properties of the materials was analyzed. The experimental results showed that an appropriate amount of EDTA can promote the formation of a flower-like morphology in Ce-doped Bi2Te3 nanomaterials and enhance their thermoelectric properties. The ZT values of the x = 0.15 sample made by the better flower-like morphology of nanopowders are all around 1, which reach 1.15 at 398 K. This work demonstrates the synergistic effects of combining nanostructure engineering and chemical doping strategies for thermoelectric performance enhancement.

Surface passivation of red-emitting fluoride phosphors by aminocarboxyl complexants to achieve high water-resistance for light-emitting diodes

Mn4+-activated fluoride phosphors are promising luminescent materials for use in phosphor-converted white-light-emitting diodes (wLEDs). However, poor water resistance in high humidity environment, one of critical drawbacks of this type of phosphors, has limited their practical applications. To address this issue, we developed a new facile strategy to passivate the surface of phosphors by in situ constructing a dual Mn4+-rare protective layer using well-known aminocarboxyl complexants with mild reducibility and strong complexation property. Ethylenediamine tetraacetic acid (EDTA) was taken as a representative for the research in detail, and a typical Mn4+-doped fluorosilicate phosphor K2SiF6:Mn4+ (KSFM) was selected to demonstrate the reliability of the proposed strategy. The surface passivation was achieved by simply dispersing KSFM in a saturated EDTA aqueous solution (KSFM-sEDTA) or a hydrofluoric acid solution containing a certain amount of EDTA (KSFM-EDTA), and then stirring for a short time at room temperature. The analysis results indicate that the dual Mn4+-rare surface layer is composed of a K2SiF6 matrix shell and an organic coating of residual EDTA and/or its related compounds, and the layer constructed by Method 2 is more significant than that by Method 1. Both the luminescence performance and the water resistance of the passivated KSFM were greatly enhanced while the luminescence characteristics remained unchanged. When the water-eroded KSFM was re-treated with EDTA, the luminescence was dramatically restored due to removal of the manganese hydrolysates and repair of the crystal surface defects. The wLEDs assembled with KSFM-EDTA and KSFM-sEDTA phosphor exhibited intense white light with high luminous efficiency (LE, 170.61 lm/W and 162.51 lm/W), high color rendering index (CRI, 88.3 and 85.9), and low correlated color temperature (CCT, 3680 K and 3805 K), respectively. More importantly, the fabricated wLEDs retained high LE (90.6% and 88.6%) and no remarkable changes of CRI and CCT values after being aged at high temperature and humidity (85 °C, 85%) for 550 h, which are more superior to the wLED assembled with the pristine KSFM.

Solution Combustion Synthesis of Ni-Based Nanocatalyst Using Ethylenediaminetetraacetic Acid and Nickel-Carbon Nanotube Growth Behavior.

We studied the influence of the ethylenediaminetetraacetic acid (EDTA) content used as combustion fuel when fabricating nickel oxide (NiO) nanocatalysts via solution combustion synthesis, as well as the growth behavior of carbon nanotubes (CNTs) using this catalyst. Nickel nitrate hexahydrate (Ni(NO3)2∙6H2O) was used as the metal precursor (an oxidizer), and the catalysts were synthesized by adjusting the molar ratio of fuel (EDTA) to oxidizer in the range of 1:0.25 to 2.0. The results of the crystal structure analysis showed that as the EDTA content increased beyond the chemical stoichiometric balance with Ni(NO3)2∙6H2O (F/O = 0.25), the proportion of Ni metal within the catalyst particles decreased, and only single-phase NiO was observed. Among the synthesized catalysts, the smallest crystallite size was observed with a 1:1 ratio of Ni ions to EDTA. However, an increase in the amount of EDTA resulted in excessive fuel supply, leading to an increase in crystallite size. Microstructure analysis revealed porous NiO agglomerates due to the use of EDTA, and differences in particle growth based on the fuel ratio were observed. We analyzed the growth behavior of CNTs grown using NiO nanocatalysts through catalytic chemical vapor deposition (CCVD). As the F/O ratio increased, it was observed that the catalyst particles grew excessively beyond hundreds of nanometers, preventing further CNT growth and leading to a rapid termination of CNT growth. Raman spectroscopy was used to analyze the structural characteristics of CNTs, and it was found that the ID/IG ratio indicated the highest CNT crystallinity near an F/O ratio of 1:1.

Effect of EDTA addition on the biotribological properties of coatings obtained from PEO on the Ti6Al4V alloy in a phosphate-based solution

Coatings were obtained on the Ti6Al4V alloy by Plasma Electrolytic Oxidation (PEO) in a phosphate-based electrolyte with different Ethylenediaminetetraacetic acid (EDTA) concentrations. TiO2 was detected in the coatings in both anatase and rutile phases, with the incorporation of P and Ca into the coating from the electrolyte. A significant change was evidenced for samples anodized with EDTA addition, compared to the sample anodized without EDTA. The thickness was higher for coating obtained with an increased amount of EDTA sample (20.24 μm), compared to the coating anodized without EDTA (13.12 μm). All samples were anodized at galvanostatic conditions, applying a current density of 50 mA cm−2 during 1000s. A higher coating thickness leads to the formation of higher intensity micro-discharges, which promotes the formation of a higher amount of rutile phase, in the coatings with higher EDTA content in the anodizing electrolyte. The friction and wear properties of coatings were analyzed in a ball-on-disk tribometer, under lubricated conditions in simulated body fluid (SBF). The coatings substantially improved the wear behavior of the Ti6Al4V alloy. The coating with a higher amount of EDTA exhibits better tribological performance (6 times better than the substrate (Wear rate: 22.077 × 10−10 Kg/N.m)), due to the higher amount of rutile into the coating, which reduces the wear rate as well as the friction coefficient.

Intense removal of Ni (Ⅱ) chelated by EDTA from wastewater via Fe3+ replacement–chelating precipitation

Efficient removal of Ni (Ⅱ) chelated by ethylenediaminetetraacetic acid (EDTA) from wastewater remains an important but challenging environmental problem. Therefore, a novel strategy of Fe3+ replacement–chelating precipitation was proposed to remove Ni (Ⅱ) chelated by EDTA from simulated Ni-EDTA wastewater and real electroless nickel plating wastewater. The strategy was proved to be thermodynamically feasible by DFT calculation. Regardless of the simulated Ni-EDTA wastewater or the real electroless nickel plating wastewater, the residual nickel in the wastewater was less than 0.1 mg/L that satisfied the discharge standard after being treated under optimal conditions using this strategy. Moreover, the strong acidity and Fe3+ could increase the proportion of free Ni2+ in Ni-EDTA wastewater, thereby enhancing the Ni removal efficiency. Additionally, the total amount of EDTA in wastewater was basically unchanged, since the structure of EDTA was not destroyed by this strategy, while its chemical form changed from Ni-EDTA complex to Fe3+-EDTA complex. Furthermore, the mechanism was systematically studied by electronic structure analysis, solution chemistry, UV-Vis spectral, FT-IR spectral and X-ray photoelectron spectroscopy. At last, this strategy is a promising approach and it can provide a reference for the treatment of other similar heavy metal wastewater.

Improvement of phosphorus release from sludge by combined electrochemical-EDTA treatment.

In this paper, combined with the addition of ethylenediaminetetraacetic acid (EDTA), the electrochemical treatment of waste activated sludge (WAS) was investigated to explore its effect on the release of phosphorus (P) from WAS. The results showed that during the electrochemical treatment, the addition of EDTA could significantly promote the release of P from the WAS to the supernatant, the optimal amount of EDTA was 0.4 g/g total suspended solids (TSS), when the release of total dissolved phosphorus (TDP), organic phosphorus (OP) and molybdate reactive phosphorus (PO43--P) were 187.30, 173.84 and 13.46 mg/L, respectively. OP was the most likely form of P to be released during this process. Moreover, combined electrochemical-EDTA treatment could promote the release of P and metal ions from extracellular polymeric substances (EPSs) to the supernatant, and increase the solubility and disintegration of sludge. EDTA chelated the metal ions of sludge flocs and phosphate precipitates to cause sludge floc decomposition, thereby promoting the release of P from WAS.

Heterogeneous Fenton-like degradation of EDTA in an aqueous solution with enhanced COD removal under neutral pH.

By providing the key carbon and nitrogen elements needed for eutrophication, the potential toxicity of ethylenediaminetetraacetic acid (EDTA) prompts the exploration of effective treatment methods to minimize the amount of EDTA released into the environment. In this study, Fe3O4 magnetic nanoparticles (MNPs) were prepared and used as catalysts to study the mineralization of EDTA in Fenton-like reactions under neutral pH. Fe3O4 MNPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET). The effects of pH, ferric ion leaching, and H2O2 concentration on chemical oxygen demand (COD) removal of EDTA were investigated. The morphological characterization of the nanoparticles suggests a quasi-spherical structure with small particle size and a surface area of 49.9 m2/g. The results show that Fe3O4 MNPs had good catalytic activity for the mineralization of EDTA under pH 5.0-9.0. The optimum conditions for the COD removal of 45% at pH 7.0 were: 40 mM H2O2, 10 mM Fe3O4, and 1 g/L EDTANa2·2H2O at 303 K. Fe3O4 MNPs maintained high catalytic activity after five cycles of continuous degradation of EDTA. According to reactive oxidizing species measurements obtained by electron spin resonance (ESR), it was confirmed that HO· free radicals, presented in the H2O2/Fe3O4 MNPs heterogeneous Fenton-like reaction, were the primary active group in the removal of EDTA. These features can be considered beneficial to the application of Fe3O4 MNPs towards industrial wastewater treatment.

Enhanced electrochemical performance via PPy encapsulated 3D flower-like bismuth molybdate nanoplates for high-performance supercapacitors

Novel three-dimensional (3D) flower-like Bi2MoO6 (BMO) nanoplates were successfully synthesized by a hydrothermal method using ethylenediaminetetraacetic acid (EDTA) as a capping agent. The growth mechanism of the 3D flower-like BMO nanoplates was investigated by varying the amount of EDTA during the reaction. The electrochemically conductive BMO/polypyrrole (PPy) hybrid composite was further prepared by in-situ oxidative polymerization method by adding the pyrrole monomer into the aqueous solution of pristine BMO. The X-ray diffraction patterns of the PPy polymer did not show any change on the phase form of the pristine BMO. The electrochemical properties of the PPy coated BMO hybrid composite electrode as well as the prepared 3D flower-like BMO nanoplate electrode were evaluated in 1 M KOH electrolyte solution. The specific capacitance of the BMO/PPy hybrid composite electrode exhibited the higher specific capacitance value (1253 F g−1), which is much higher than the pristine 3D flower-like BMO nanoplate electrode (725 F g−1) at a current density of 1 A g−1. Furthermore, the BMO/PPy hybrid composite electrode maintained 70.4% of capacitance retention after 2000 cycles with respect to the initial specific capacitance value at a higher current density (15 A g−1), which indicates that the electrode material has good cycling stability.

Rapid growth of Sb2S3 thin films by chemical bath deposition with ethylenediamine tetraacetic acid additive

Sb2S3 is a suitable photovoltaic material because of its favorable optoelectronic properties as well as being comprised of earth-abundant and nontoxic precursor elements. The chemical bath deposition method has been widely used to deposit Sb2S3 thin films. However, longer deposition times as well as multiple depositions have been reported to prepare thicker Sb2S3 films. In order to produce good quality Sb2S3 films with a thickness greater than 1 μm within a short deposition time, we have added a small amount of ethylenediamine tetraacetic acid (EDTA) to the conventional chemical proportions used for the deposition of Sb2S3 films. The effect of EDTA, Na2S2O3, bath temperature, and the deposition time were studied. By optimizing these conditions, uniform good quality Sb2S3 thin films with a thickness greater than 1 μm could be obtained in a short deposition time of 3 h. The films prepared at the optimized conditions were annealed to improve the crystallinity. The films exhibited orthorhombic crystal structure with lattice parameters a = 1.142 nm, b = 0.381 nm, and c = 1.124 nm, and a direct optical band gap of 1.66 eV. This approach is beneficial for obtaining good quality Sb2S3 films which is ideal for solar cell applications.

Synthesis and visible light photocatalytic properties of Bi2Fe4O9 particles via EDTA-assisted sol–gel route

Submicron Bi2Fe4O9 particles could be obtained by applying a modified sol–gel synthesis at the temperature of 650 °C, with ethylenediaminetetraacetic acid (EDTA) as chelating agent. SEM images showed that morphology and grain size of the as-prepared powders were influenced by calcination temperature. Bi2Fe4O9 pure phase could be controlled by adjusting the amount of EDTA. Correspondingly, the crystal growth and morphology evolution mechanism in the reactions were discussed. Additionally, the photocatalytic properties of the particles were explored. The Bi2Fe4O9 particles synthesized with 5 mmol EDTA showed the highest photocatalytic activity toward methyl orange and rhodamine-B degradation under visible light irradiation, the degradation rate could be as high as 93 and 99 % in 3 h with the aid of H2O2, respectively.

EDTA-mediated morphology and tunable optical properties of Eu3+-doped NaY(MoO4)2 phosphor

Uniform and well-crystallized NaY(MoO4)2: Eu3+ 3D hierarchical flower-like architectures self-assembled from different building blocks have been successfully synthesized by a facile ethylene diamine tetraacetic acid (EDTA)-mediated hydrothermal route. The crystalline phase, size, morphology, and down-conversion luminescence properties were systematically characterized using powder X-ray diffraction, field emission-scanning electron microscopy, photoluminescence (PL) and photoluminescent excitation spectra (PLE), respectively. It was found that the pH value in the initial solution was responsible for the crystal phase determination of final products. The experimental results showed that the amount of EDTA was a key parameter which not only determined their spacial arrangement, but also affected the down-conversion luminescence intensity of the final products. In PL spectrum, a prominent red emission was observed due to the hypersensitive 5D0 → 7F2 transition, and the optimum doping level of Eu3+ was 20 %. Two strongest lines at 396 and 467 nm in excitation spectra of these phosphors matched well with the two popular emissions from near ultraviolet and blue GaN-based LEDs, so they could be explored for an efficient red region for white light-emitting diodes.

Hydrothermal preparation of BiVO4 photocatalyst with perforated hollow morphology and its performance on methylene blue degradation

Monoclinic scheelite type BiVO4 samples with high photocatalytic activity were successfully synthesized by a hydrothermal method in the presence of ethylenediamine tetraacetic acid (EDTA). Monoclinic scheelite structure was obtained at a hydrothermal temperature as low as 140°C, which was much lower than 210°C in the absence of EDTA. Experimental results indicate that the morphology of the BiVO4 changed from sphere, polygon with hole, perforated hollow polygon, to particle with fragment with the increase of EDTA amount, and the particle size also decreased. On the conditions of the hydrothermal temperature of 170°C, pH of 7.0, hydrothermal time of 4h and the amount of EDTA of 3.0mmol, BiVO4 samples with perforated hollow polygon structure and low band gap of 2.48eV were obtained. Catalyzed by the perforated hollow polygon BiVO4, the discoloration rate of methylene blue (MB) reached 90.84% in simulated sunlight. The high discoloration rate of BiVO4 was successfully explained by the experiment results of crystal structure, morphology, UV–vis diffuse reflectance spectroscopy and band gap.

A complexant-assisted hydrothermal route for the synthesis of nickel phosphide

Dendritic Ni2P microstructures were successfully synthesized by a facile hydrothermal route. X-ray powder diffraction, energy dispersive X-ray spectrometer analysis, and Field-emission scanning electron microscopy were used to characterize the as-obtained products. The results showed that the as-prepared product had a hexagonal phase and was composed of a large quantity of well-defined dendrites which have the secondary branch-like structure. Further study shows that the morphology of the as-obtained Ni2P microstructures was highly dependent on the amount of ethylenediamine tetraacetic acid, the reaction temperature, and the reaction time. Then based on some captured intermediates, a possible growth mechanism of the as-obtained Ni2P dendrites was proposed.

A nontoxic and low-cost hydrothermal route for synthesis of hierarchical Cu2ZnSnS4 particles.

We explore a facile and nontoxic hydrothermal route for synthesis of a Cu2ZnSnS4 nanocrystalline material by using l-cysteine as the sulfur source and ethylenediaminetetraacetic acid (EDTA) as the complexing agent. The effects of the amount of EDTA, the mole ratio of the three metal ions, and the hydrothermal temperature and time on the phase composition of the obtained product have been systematically investigated. The addition of EDTA and an excessive dose of ZnCl2 in the hydrothermal reaction system favor the generation of kesterite Cu2ZnSnS4. Pure kesterite Cu2ZnSnS4 has been synthesized at 180°C for 12 h from the reaction system containing 2 mmol of EDTA at 2:2:1 of Cu/Zn/Sn. It is confirmed by Raman spectroscopy that those binary and ternary phases are absent in the kesterite Cu2ZnSnS4 product. The kesterite Cu2ZnSnS4 material synthesized by the hydrothermal process consists of flower-like particles with 250 to 400 nm in size. It is revealed that the flower-like particles are assembled from single-crystal Cu2ZnSnS4 nanoflakes with ca. 20 nm in size. The band gap of the Cu2ZnSnS4 nanocrystalline material is estimated to be 1.55 eV. The films fabricated from the hierarchical Cu2ZnSnS4 particles exhibit fast photocurrent responses under intermittent visible-light irradiation, implying that they show potentials for use in solar cells and photocatalysis.

Microwave hydro/solvothermal synthesis of octahedron-like NaEu(MoO4)2 microarchitectures by EDTA-assisted and photoluminescence property

Octahedron-like NaEu(MoO4)2 microarchitectures with tetragonal scheelite-type structure have been successfully synthesized by a facile ethylene diamine tetraacetic acid (EDTA)-mediated microwave hydrothermal method. The as-prepared products were characterized by X-ray diffractometer, scanning electron microscope and photoluminescence. The particle size and morphology of NaEu(MoO4)2 can be tuned effectively by adjusting reaction temperature, reaction time, the amount of EDTA and ethylene glycol. Remarkably, the morphologies were the microflakes, micro-octahedrons, when the amount of EDTA was increased from 0 to 0.01 g at 180 °C. The excitation spectrum of the calcined NaEu(MoO4)2 micro-octahedron was observed with a maximum peak at near ultraviolet excitation (λex = 393 nm). Its emission spectrum was recorded under a excitation wavelength of 393 nm and exhibited the most intensitive red emission at 615 nm. This indicates the photoluminescence properties were strongly dependent on crystal morphology and crystallinity. So the calcined NaEu(MoO4)2 micro-octahedron has the potential to be applied in many LED devices.

NaY(MoO4)2 microcrystals with controlled faceting and their tunable photoluminescence properties after doping with Eu3+

We present a facile synthesis of NaY(MoO4)2 microcrystals with controlled morphologies and tunable faceting via an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal method. Three different types of NaY(MoO4)2 microcrystals, namely, sharp bipyramids, truncated bipyramids, and quasi-cubes, can be selectively produced, and the percentage of {001} and {101} facets in the tetragonal bipyramidal NaY(MoO4)2 microcrystals can be engineered through the judicious choice of an appropriate amount of EDTA. The preferential adsorption of EDTA on {001} facets of the NaY(MoO4)2 crystal is responsible for the morphology evolution of the NaY(MoO4)2 microcrystals from sharp bipyramids to quasi-cubes. The present synthetic approach is also extendable to achieve NaHo(MoO4)2 and NaTb(MoO4)2 microcrystals with different shapes and tunable exposed facets. It is found that the luminescence properties of the NaY(MoO4)2:Eu3+ microcrystals are highly dependent on their shape and size, and the sharp NaY(MoO4)2:Eu3+ bipyramids exhibit the strongest emission intensity due to their larger size, fewer defects and less exposed facets. As such, the sharp NaY(MoO4)2:Eu3+ bipyramids may have potential applications in light display systems as well as optoelectronic devices, while the present EDTA-mediated hydrothermal synthetic strategy represents a potentially general route to the generation of nano/microcrystals with shape- and exposed facet-control.

Functionalization of graphene with nitrogen using ethylenediaminetetraacetic acid and their electrochemical energy storage properties

Recently there has been a considerable focus on the synthesis of nitrogen functionalized graphene for energy storage and conversion. Herein, we report a simple, economical and facile process for the synthesis of nitrogen containing graphene composite which can be scaled up for mass production by using a nitrogen containing organic compound, ethylenediaminetetraacetic acid (EDTA) and graphene oxide as precursors. From the XRD studies, the increase in the interlayer distance between the graphene sheets confirms the functionalization of graphene sheets and the FT-IR spectroscopic analysis revealed the presence of N-containing functional groups in N-doped graphene sheets. XPS analysis confirms the chemical nature of N-containing functional groups, and TG analysis showed the amount of EDTA loaded on the graphene sheets. This composite exhibits a large specific capacitance of 290 F g−1 at 0.1 A g−1 with a capacitance retention of 67% and 58% at high current densities of 10 and 20 A g−1, respectively, thereby showing superior rate capability. In addition, it showed long-term electrochemical stability through 6000 charge–discharge cycles even at a high current density of 5 A g−1 with a specific capacitance loss of 2%.

Effects of Ethylenediamine Tetraacetic Acid on the Texture and Magnetic Properties of Barium Ferrite Films

M-type barium ferrite thin films with hexagonal platelets on sapphire were fabricated by spin-coating of precursors. Fourier-transform infrared spectra indicated that bonds between the metal and oxygen were formed at about 500°C. X-ray diffraction showed that the films had preferred c-axis orientation. Surface morphology of the film was investigated by scanning electron microscopy. Textures of the films were influenced by the amount of ethylenediamine tetraacetic acid (EDTA). The film with the least pores and the most c-axis-textured platelet hexagonal grains was obtained when the ratio of EDTA to metal ions was 1.0. At the same time, the magnetic hysteresis loops in directions parallel and perpendicular to the film plane demonstrated that the films were almost isotropic. The maximum coercive forces of 43.23 kA/m in plane and 54.70 kA/m out of plane were achieved when the ratio of the amount of EDTA to metal ions was 0.5. The highest in-plane remanence ratio was 0.32 when the ratio of EDTA to metal ions was 1.5, while the highest out-of-plane value was 0.28 in the other two cases.

An EDTA-assisted hydrothermal synthesis of BiVO4 hollow microspheres and their evolution into nanocages

BiVO4 hollow microspheres have been synthesized in the presence of ethylenediaminetetraacetic acid (EDTA) by a microwave hydrothermal method. The as-prepared hollow microspheres were composed of hundreds of nanorods. Increasing the amount of EDTA produced a new nanocage structure. The evolution process of BiVO4 with different microstructures indicated that the amount of EDTA added played a crucial role in determining the shape of the samples. Additionally, it was found that the existence of EDTA was vital to mediate the crystal growth, and the hydrothermal time and temperature were key parameters in determining the BiVO4 morphologies. A possible formation mechanism is proposed.

SET LRP of MMA mediated by Fe(0)/EDTA in the presence of air

In this work, single electron transfer-living radical polymerization (SET LRP) of methyl methacrylate was successfully carried out using CCl4 as initiator and Fe(0)/ethylenediaminetetraacetic acid (EDTA) as catalyst at 25 °C in dimethyl sulfoxide in the presence of air. In addition, ascorbic acid (VC) was used as reducing agent in the polymerization. Kinetics experiments demonstrated that the SET LRP is a ‘living’ polymerization, for example, the ln([M]0/[M]) versus time is linear and the number-average molecular weight values increases with respect to monomer conversion with narrow polydispersities. The amount of EDTA and VC had a profound effect on the polymerization. The ‘living’ characteristics were further verified by chain extension.