Na2EDTA Concentration Research Articles

Controllable synthesis of snowflake‐like α‐calcium sulfate hemihydrate microstructures using Na2EDTA as morphology modifier

AbstractIn this work, snowflake‐like α‐CaSO4·0.5H2O (α‐CSH) hierarchical architectures were successfully synthesized by a facile one‐pot method in an ethylene glycol‐water system using Na2EDTA as a crystal morphology modifier. Characterization techniques including X‐ray diffraction (XRD), thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) confirmed the progressive morphological evolution of α‐CSH from rods to snowflake‐like structures ultimately to hexagonal plates with increased Na2EDTA concentrations. The results revealed that Na2EDTA concentration played a critical role in directing the crystallization and self‐assembly of α‐CSH, and a mechanism is proposed where Na2EDTA modulated crystal orientation through preferential adsorption and regulated the driving forces between ion‐mediated crystallization and particle‐mediated assembly. This work puts forward a simple yet effective strategy for facilely regulating the morphology of α‐CSH microstructures, which could potentially expand their applications across diverse fields such as composites, construction, biomedicine, and drug delivery.

Spectrophotometric and Smartphone-based Dual Monitoring Method for the Determination of Al(III) Ions Using Fermented Black Carrot Juice (Şalgam/Shalgam) as a Green Chromogenic Agent

In this study, anthocyanin-rich fermented black carrot juice (şalgam/shalgam) was used as a chromogenic agent in order to develop eco-friendly, low-cost, simple, fast, and practical both visible spectrophotometric and smartphone-based methods for the determination of Al(III) ions in water samples. Formation of Al(III)-anthocyanin complex results in a color change from red to purple in direct proportion to the increasing Al(III) concentration. For the spectrophotometric analysis, the analytical response of the developed method between absorbance and logarithm of Al(III) concentration exhibits a satisfying wide linear concentration range from 37.0 to 1850.0 µM. The LOD and LOQ values are 6.67 µM and 22.0 µM, respectively. For smartphone-based analysis, the analytical response of the developed method between B values and Al(III) concentration obtained a linear concentration range from 18.5 to 111.0 µM. The LOD and LOQ values are 4.40 µM and 14.5 µM, respectively. LOD values are below the acceptable limit of Al(III) in water according to WHO (7.41 µM) for both methods. The interfering effect of common water ions was investigated, and the observed interferences from Sn2+, Fe2+, and Fe3+ were easily eliminated using enough concentration of Na2EDTA without affecting the blank absorbance/B value of the Al(III)−anthocyanin complex for two monitoring methods. The selectivity of the developed method was investigated in the presence of possible species such as benzoic acid, lactic acid, amino acids, and salt. Developed spectrophotometric and smartphone-based methods applied to real water samples and validated against the reference ICP-OES method at 95% confidence level using Student’s t- and F-tests.

Co (II) desorption from silica gel and mercapto-silica hybrid

This paper aims to study Co (II) desorption from silica gel (SG) and mercapto-silica hybrids (MSH) by many desorbing agents. SG was prepared from sodium silicate from rice husk ash, whereas MSH was SG modified by organic compounds 3-(trimethoxysilyl) - 1-propanthiol. The characterization of adsorbents covered by an X-ray diffractometer and an FTIR spectrophotometer. Optimization of contact time for adsorption of Co (II) on HMS and the procedure of desorption agents (H2O, HCl, Na2EDTA.2H2O) at different contact times and concentrations via batch methods. The results showed that the optimum contact time for Co (II) adsorption on MSH was 120 minutes. The most appropriate desorbing agents for SG and MSH were HCl and Na2EDTA.2H2O. The optimum contact times for Co (II) desorption on SG and MSH were 90 and 120 minutes, respectively. The optimum concentration of HCl for desorbing Co (II) on SG was 0.025 M. While, the optimum concentration of Na2EDTA.2H2O for Co (II) desorption on MSH was 0.1 M.

Synthesis and luminescence properties of β-NaRE0.95Eu0.05F4 (RE[dbnd]Y, Lu)

On the base of β-NaYF4 and β-NaLuF4 compounds, optimal synthesis methods were selected to obtain highly crystalline Eu3+-doped compounds in the hexagonal (β) structure. The compounds β-NaY0.95Eu0.05F4 and β-NaLu0.95Eu0.05F4 were synthesized by hydrothermal synthesis. The concentration of Na2EDTA introduced into the reaction system as a modifier affects the shape and size of the product from elongated hexagonal prisms to quartz-like crystals. The thermal behavior of the compounds has been studied; the temperature of the polymorphic transition from hexagonal to cubic structure is 680°C for β-NaY0.95Eu0.05F4 and 624°C for β-NaY0.95Eu0.05F4, the melting point of α-NaRE0.95Eu0.05F4 is about 900°C. Under excitation with UV-light of λ = 393nm, β-NaY0.95Eu0.05F4 and β-NaLu0.95Eu0.05F4 show the emission lines of direct Eu3+f-f transitions, with the presence of the emission from higher Eu3+ excited states (up to 5H3) in both samples, which is responsible for the more orange color of emission instead of the usual red for Eu3+. Emission decay times are slightly longer for β-NaY0.95Eu0.05F4 than for β-NaLu0.95Eu0.05F4, which is the result of a bigger unit cell for the former, leading to longer interatomic distances between Eu3+ ions in the lattice. The luminescence mechanisms for the doped lanthanide ions were thoroughly analyzed.

A one-pot synthesis of colloidal Ag–Au nanoparticles with controlled composition

We report a one-pot synthesis method for a production of a stable Ag–Au bimetal colloidal solutions (Ag–Au hydrosols) by simply mixing disodium salt of ethylenediaminetetraacetic acid (Na2EDTA) with AgNO3 and HAuCl4 in aqueous alkaline medium at 80 °C. We found that Na2EDTA act not only as a reductant of metal ions and a potent stabilizer of metal nanoparticle size, but also as an effective agent for controlling the composition of the formed nanoparticles, owing to the high complexing affinity of Na2EDTA to silver ions. It was found that by controlling Na2EDTA concentration in the reaction mixture it is possible to control not only size and size distribution of a synthesized colloidal bimetallic Ag–Au nanoparticles, but bimetallic Ag–Au nanoparticles composition (Ag/Au ratio) as well.

Enhanced removal of aqueous Cr(VI) using optimized Fe complex on EDTA modified cotton fiber via photocatalytic reduction and adsorption hybrid functions

Cotton fabric was modified with Na2EDTA using a hydrothermal method and subsequent coordination of Fe(III) ions to produce a EDTA modified cotton fiber Fe complex (Fe-EDTA-Cotton) for the synergistic removal of Cr(VI) species from water through photocatalytic reduction and adsorption processes. High Na2EDTA concentration or hydrothermal temperature increased carboxyl group content (QCOOH) and Fe content (QFe) of the resulting Fe-EDTA-Cotton. Increasing QFe value of the complex or stronger irradiation favored the photocatalytic reduction of Cr(VI) species. Fe-EDTA-Cotton with high QCOOH value exhibited a good adsorption performance of the generated Cr(III) ions during the reaction. Thus, high photocatalytic reduction efficiency and strong Cr(III) ions capturing ability were responsible for the enhanced removal of Cr(VI) species of Fe-EDTA-Cotton as a hybrid photocatalyst in cyclic reuse.

Synthesis of gold hydrosols in the presence of Na2EDTA

The possibility of Na2EDTA applying as a reducing and stabilizing reagent in aqueous medium to obtain gold hydrosols from hydrogen tetrachloroaurate was studied. It was found that, depending on the pH of the reaction medium, both nanosized precipitates (~60 nm) and gold hydrosols, consisting of spherical nanoparticles of uniform size (12–15 nm), can be obtained. Stable gold sols are formed at pH ≥ 10.5. Sol formation process rate depends on the temperature and concentration of Na2EDTA and increases with their increase. An electrochemical study of processes of HAuCl4 reduction and Na2EDTA oxidation showed that the possibility of gold hydrosols formation in an alkaline medium is due to the kinetic inhibition of the reduction process of gold hydroxo complexes formed during this process.

Chelating-Agent-Enhanced Copper, Lead and Zinc Extraction From Iraqi Contaminated Sandy Soil.

This research aims to investigate extraction of copper, lead, and zinc from Iraqi sandy contaminated soil. Two systems were tested single and ternary component systems. Chelating agent ethylenediaminetetraacetic acid disodium salt (Na2EDTA) was utilized as extractant. Amount of 500 mg of metal per kg soil was prepared to form artificially contaminated soil. Extraction of metals was achieved using column extraction mode. Experimental tests were conducted at different conditions of Na2EDTA concentration,flow rate, and contact time. The results illustrated that the maximum removal percentages for single component system were 92% ,76% and 68% at equilibrium time 6, 8, and 8 hours for Pb , Cu and Zn, respectively. While for ternary system were 82%, 72% and 65%, respectively, at equilibrium time 6 hours for Cu and 8 hours for Pb and Zn. In addition to the best equilibrium time, the other optimum conditions for both systems were 0.1 mol/L extractant concentration, pH 4 and flow rate 20 ml/hr. The sequence of heavy metals removal was Pb > Cu >Zn. The experimental data were tested by applying it in four kinetic models; first order, two constant, parabolic diffusion, and Elovich model. Elovich and parabolic diffusion were the most fitted models to the experimental data.

Enhanced Cr(VI) removal in the synergy between the hydroxyl-functionalized ball-milled ZVI/Fe3O4 composite and Na2EDTA complexation

The application of zero-valent iron (ZVI) for Cr(VI) removal often presents limitations due to its easy passivation. In this study, a column packed with hydroxyl-functionalized ball-milled ZVI/Fe3O4 (HFB-ZVI/Fe3O4) composite, assisted with Na2EDTA complexation, was developed to achieve sustainable treatment of Cr(VI)-containing wastewater. The results showed that at influent Cr(VI) concentration of as high as 50 mg/L, effluent Cr(VI) concentration below 0.5 mg/L was sustained for bed volume of as high as 1271 BV along with 2 g/L Na2EDTA concentration. Through the hydroxyl-functionalized treatment, FeOOH coating containing surface-adhering Fe(II) on the composite surface can be formed. Hydrolysis and auto-reduction of Fe(II)/Fe(III) species caused proton accumulation, resulting in remarkable attraction of anionic Cr(VI) via electrostatic interaction and exchange. Therefore, the reduction of Cr(VI) to Cr(III) was considerably enhanced. On the other hand, Na2EDTA complexation suppressed the growth of passivation layer and generated fresh corrosion products, thereby providing additional reactive sites for Cr(VI) removal. Additionally, Na2EDTA recovery and spent column regeneration were successfully proven. The remarkable effectiveness of Cr(VI) removal from actual electroplating wastewater confirmed the potential of the HFB-ZVI/Fe3O4 composite-packed column and Na2EDTA assistance-coordinated system in full-scale application.

Multiple copper adsorption and regeneration by zeolite 4A synthesized from bauxite tailings.

Copper ions were first adsorbed by zeolite 4A synthesized from bauxite tailings, the desorption of Cu(II) using Na2EDTA solutions was performed, and the recycling of zeolite 4A in adsorption and desorption was systematically investigated. It was observed that the Cu(II) removal efficiency was directly dependent on the initial pH value. The maximum removal efficiency of Cu(II) was 96.2% with zeolite 4A when the initial pH value was 5.0. Cu(II) was completely absorbed in the first 30min. It was also observed that the desorption efficiency and zeolite recovery were highly dependent on the initial pH and concentration of Na2EDTA in the solution. The desorption efficiency and percent of zeolite recovered were 73.6 and 85.9%, respectively, when the Na2EDTA solution concentration was 0.05molL-1 and the pH value was 8. The recovered zeolites were pure single phase and highly crystalline. After 3cycles, the removal efficiency of Cu(II) was as high as 78.9%, and the zeolite recovery was 46.9%, indicating that the recovered zeolites have good adsorption capacity and can repeatedly absorb Cu(II).

Selective recovery of lead from zinc oxide dust with alkaline Na2EDTA solution

The selective recovery of lead from the zinc oxide dust using an alkaline Na2EDTA solution was investigated. The effects of temperature, leaching time, Na2EDTA concentration and initial NaOH concentration on the leaching rates of lead and zinc were studied. The following optimized leaching conditions were obtained: liquid-to-solid ratio 5:1 mL/g, stirring speed 650 r/min, Na2EDTA concentration 0.12 mol/L, initial NaOH concentration 0.5 mol/L, leaching temperature 70 °C, leaching time 120 min. Under the optimized conditions, the average leaching rates of lead, zinc, fluoride and chloride are 89.92%, 0.94%, 62.84% and 90.02%, respectively. The filtrate was used to electrowin lead powders. The average current efficiency of electrowinning is about 93% and lead content is higher than 98% under the conditions of temperature of 60 °C, current density of 200 A/m2, H3PO4 concentration of 1.5 g/L, and lead ion concentration of above 5 g/L. The consumption of Na2EDTA and the direct current are about respectively 0.218 kg and 0.958 kW·h for per kilogram of lead powder.

Size-controlled synthesis of Rod-like α-FeOOH nanostructure

One-dimensional goethite (α-FeOOH) nanorods were successfully fabricated by a hydrothermal route without any template. Experimental results reveal that concentrations of Fe3+ and ethylenediaminetetraacetic disodium salt (Na2EDTA) affect the phase composition and size of the as-synthesized products. The size of the rod-like α-FeOOH increased when the concentration of Na2EDTA was increased, where Na2EDTA acts as a nucleation inhibitor. α-Fe2O3 nanoparticles were produced when the concentration of Fe3+ was increased from 0.02 to 0.08 and 0.40M. A possible formation mechanism was proposed based on the results of the time dependent experiments. Different electrolytes and surfactants can affect the size and the aspect ratio of the as-prepared nanorod-like α-FeOOH. Na2SO4 induced the decreasing of the size of the as-prepared sample. KCl and PVP affected the aspect ratio of the nanorods.

Modeling of permeabilization process in Pseudomonas putida G7 for enhanced limonin bioconversion

A facile process of enhanced whole cell biotransformation to debitter the triterpenoid limonin in citrus juices was optimized in this work. To maximize bioconversion, permeabilization conditions were modeled using response surface methodology. A central composite rotatable design with four significant variables (concentration, temperature, pH, and treatment time) was employed. The second order polynomial equations with R² values above 0.9 showed good correspondence between experimental and predicted values. The concentration, temperature, pH, and treatment time as well as their interactions had significant effects (p < 0.001) on limonin bioconversion. The optimum operating conditions for permeabilization were observed at a Na₂EDTA concentration of 1.5 μM, treatment time of 15 min, temperature of 28 °C, and pH 8. A maximum reduction of 76.71% in the limonin content was achieved within 150 min under selected conditions. The results are promising for refining permeabilization technique for whole cell biocatalysts thereby improving the debittering of citrus juices significantly.

Cadmium extraction from phosphate ore. Effect of microwave

This study discusses the operating variables for removal of cadmium from phosphate ore using Na2EDTA. These variables include the reaction time, Na2EDTA concentration, liquid/phosphate ore ratio, number of extractions and microwave extraction. Na2EDTA induced a two-step extraction process including a rapid extraction within the first hour, and a subsequent gradual release that occurred over the following hours. The cadmium extraction efficiency increased progressively with the increasing of Na2EDTA concentration. The extraction efficiency of cadmium increased with increasing liquid/phosphate ratio in the 5–200 range. Consecutive extractions using low concentrations were more effective than a single soil extraction with concentrated Na2EDTA. Microwave was beneficial to improve the removal in soil washing, and using microwave could partly substitute for agitation.

Controlled synthesis, growth mechanism and optical properties of FeWO4 hierarchical microstructures

Monoclinic ferrous tungstate (FeWO4) microcrystals with hierarchical nano/microstructures have been selectively synthesized via a facile hydrothermal process in the presence of ethylenediamine tetraacetic acid disodium salt (Na2EDTA) and hexamethylenetetramine (HMT). HMT played triple roles as the reducing agent, alkaline source, and crystal growth modifier, while Na2EDTA served as the chelating reagent and structure-directing agent. The appropriate conditions for synthesis of multilayer flower-like FeWO4 were 200 °C and 8 h with the concentrations of Na2EDTA and HMT at 0.03 mol L−1 and 0.025 mol L−1, respectively. The morphology of FeWO4 showed dramatic changes from a bulky amorphous crystal to multilayer hexangular microcrystals with increasing Na2EDTA concentration, while increasing HMT concentration would transform the hexagonal structure to a sixfold symmetry architecture and the aspect ratio of symmetry axis decreased gradually. Ostwald ripening and the self-assembled process was proposed for the possible formation mechanism. The photoluminescence (PL) intensity of the multilayer FeWO4 microcrystals was higher than that of other FeWO4 structures. Magnetic measurement of hexangular FeWO4 microcrystals showed a small ferromagnetic ordering at low temperature. Furthermore, this work may open novel routes to the chelating reagent-assisted synthesis of hierarchical architectures with various morphologies.

A facile synthesis of SrWO 4 nanobelts by the sonochemical method

SrWO 4 nanobelts have been synthesized via a facile and fast sonochemical route. The samples were characterized by XRD, SEM and TEM techniques. Experimental results showed that the concentration of Na 2EDTA and high-intensity ultrasonic irradiation played important roles in controlling the morphologies of SrWO 4. Room-temperature photoluminescence of SrWO 4 with various morphologies have also been investigated. Results showed that SrWO 4 nanobelts possessed good photoluminescent properties, suggesting that SrWO 4 nanobelts could be used in novel optoelectronic devices.

&lt;b&gt;Influence of complexing agent (Na&lt;sub&gt;2&lt;/sub&gt;EDTA) on chemical bath deposited Cu&lt;sub&gt;4&lt;/sub&gt;SnS&lt;sub&gt;4&lt;/sub&gt; thin films&lt;/b&gt;

The quality of thin film is influenced by the presence of complexing agents such as Na2EDTA. The Cu4SnS4 thin films were deposited onto indium tin oxide glass substrate by chemical bath deposition method. The structural, morphological and optical properties of the deposited films have been studied using X-ray diffraction, atomic force microscopy and UV-Vis spectrophotometer, respectively. The XRD data showed that the films have a polycrystalline and orthorhombic structure. It also indicated that the most intense peak at 2q = 30.2° which belongs to (221) plane of Cu4SnS4. The film deposited with 0.05 M Na2EDTA showed good uniformity, good surface coverage with bigger grains and produced higher absorbance value. The band gap energy varies with the variation of Na2EDTA concentration which ranging from 1.56-1.60 eV. Deposition at concentration of 0.05 M Na2EDTA proved to offer a reasonably good Cu4SnS4 thin film. KEY WORDS: Chemical bath deposition, Complexing agents, Thin films, X-ray diffraction Bull. Chem. Soc. Ethiop. 2010, 24(2), 259-266.

Hydrothermal synthesis of well-dispersed YVO 4:Eu 3+ microspheres and their photoluminescence properties

Spherical-shaped Eu-doped yttrium orthovanadate (YVO 4:Eu 3+) powders were fabricated via disodium ethylenediamine tetraacetate (Na 2EDTA)-assisted hydrothermal technique. The as-synthesized YVO 4:Eu 3+ microspheres were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). The experimental results showed that the morphology and size of the microspheres had a strong dependence on the concentration of Na 2EDTA and the reaction time of hydrothermal treatment. Spherical YVO 4:Eu 3+ crystals with the diameter of 1.0–3.0 μm were obtained in the presence of 0.025 M Na 2EDTA at 180 °C for 24 h. The photoluminescence measurement revealed that YVO 4:Eu 3+ powders with well-spherical shape have better red luminescence properties among all the samples.

The effect of excessive disodium ethylene diamine tetraacetic acid (Na&lt;sub&gt;2&lt;/sub&gt;EDTA) anticoagulant concentration on leukocytes profile in peripheral blood examination

Accuracy of leukocytes profile assessment is influenced by several pre analytical factors, among others, the anticoagulant concentration. EDTA is one of the most frequently used anticoagulant in peripheral blood examination. Several references stated that inappropriate concentration of EDTA anticoagulant in blood sample may affect the result of leukocytes profile in peripheral blood examination. The aim of this study was to evaluate whether there are differences among leukocytes profile in peripheral blood examination specimens, which were prepared with excessive Na2EDTA anticoagulant in different concentration. This study was conducted in Faculty of Medicine, Gadjah Mada University. Blood samples from 30 subjects were taken using vein puncture. Two millimeters blood was divided into 4 Na2EDTA-containing tubes. Before that, one drop of blood without Na2EDTA anticoagulant was used to make blood film right after vein puncture, as control. Each tubes contained different concentration of anticoagulant. The first tube contained Na2EDTA in standard concentration 2 mg/ml; the remaining tubes contained 4 mg/ml, 6 mg/ml, and 8 mg/ml respectively. These samples were immediately examined using SYSMEX SE-9500 automatic cell counter to measure the total and differential leukocytes count; and were stained with Wright staining for morphological examination under the microscope. These procedures were done before 20 minutes of vein puncture. There were significant decrement of total leukocytes count, absolute differential leukocytes count and monocyte percentage following excessive Na2EDTA administration. Neutrophil percentage was found to be relatively increased and the difference was significant. Lymphocyte, eosinophil and basophil percentages were not significantly different. Morphological examination showed significant increment in irregular cytoplasm margin, vacoulation and irregular nuclei lobes following excessive Na2EDTA administration. It is concluded that excessive concentration of Na2EDTA used in blood specimen preparation, will lead to changes in leukocytes profile as the concentration increased. Standard Na2EDTA anticoagulant concentration did not alter any leukocytes count and morphology, except for irregular cytoplasm margin and irregular nuclei lobes. (Med J Indones 2007; 16:168-75)

An automated alkaline elution system: DNA damage induced by 1,2-dibromo-3-chloropropane in vivo and in vitro

An automated alkaline elution system for the detection of DNA damage has been developed. After manual application of samples, which is completed within 5 min, the subsequent supply of liquids, changes in flow rates, and temperature are controlled automatically. The system operates 16 filters and may easily be expanded. The sensitivity of the fluorometric DNA determinations with the Hoechst 33258 dye is increased by using an elution buffer (20 m m Na 2EDTA, pH 12.50) with low background fluorescence. DNA is determined using an automated setup similar to the one recently presented by Sterzel et al. (1985, Anal. Biochem. 147, 462–467). The most significant modification is the use of a neutralization buffer which allows variations in the pH of eluted fractions. This change increases the sensitivity of the DNA measurements. The automated alkaline elution system was evaluated using the nematocide 1,2-dibromo-3-chloropropane (DBCP) in a study of its genotoxic effects in the testes and the kidneys. Significant DNA damage was induced in testicular cells by 2.5 μ m DBCP (1 h) in vitro and 85 μmol/kg DBCP ip (3 h) in vivo. The damage appeared after short treatment times (10 min in vivo). Variations in the observed DBCP response in vivo were largely due to interanimal variations. The automated alkaline elution system proved to be a sensitive assay also for the detection of DNA damage in kidney nuclei prepared from rats exposed to DBCP. Provided that kidney nuclei from untreated rats, mice, or hamster were kept ice-cold until lysing, 85–100% of their DNA was retained after 16 h of elution, indicating highly intact DNA. Under the same conditions, guinea pig DNA was rapidly degraded unless the nuclei were prepared in a buffer with a higher concentration of Na 2EDTA (20 m m).