Ethylenediaminetetraacetic Disodium Research Articles

Dissolution of Soap Scum by Surfactant. Part II: Effects of NaCl and Added Chelant on Equilibrium Solubility and Dissolution Rate of Calcium Soap Scum in Amphoteric Surfactant Solutions

AbstractThe effects of solution pH and NaCl on the equilibrium solubility and dissolution rate of a model soap scum (calcium octadecanoate or calcium stearate) in aqueous solutions of dimethyldodecylamine oxide surfactant (DDAO) with and without chelant disodium ethylenediaminetetraacetate are reported. The equilibrium solubility and dissolution rate of soap scum increased with increasing solution pH when the chelant was added in the DDAO system while in the chelant‐free systems the opposite trend was observed. The added NaCl has an ambiguous effect on the solubility and dissolution rate of soap scum in the absence of chelant, but a small level of added NaCl reduces both solubility and the dissolution rate constant in the presence of chelant. Both equilibrium and kinetics of dissolution are maximized at high pH with DDAO/chelant and no added salt.

Microencapsulation of Lactobacillus acidophilus CGMCC1.2686 via emulsification/internal gelation of alginate using Ca-EDTA and CaCO3 as calcium sources

Emulsification/internal gelation is an effective encapsulation method to protect probiotics from adverse environment. In this paper, microcapsules of Lactobacillus acidophilus CGMCC1.2686 were prepared by emulsification and gelation of alginate solutions with slow release of Ca2+ ions from calcium carbonate (CaCO3) and calcium disodium ethylenediaminetetraacetate (Ca-EDTA). Physical characterization of the two types of microcapsules showed that alginate-Ca-EDTA microcapsule was more uniform in size than alginate-CaCO3, with a span factor of 0.96 and 1.20, respectively. Mechanical measurements demonstrated that alginate-CaCO3 microcapsule was more robust and elastic, which was supported by its denser structure as observed by electron scanning microscopy. Bacteria encapsulation yields in the two microcapsules were similar, 37.9% for alginate-CaCO3 and 36.9% for alginate-Ca-EDTA. However, alginate-CaCO3 microcapsule exhibited much higher cell survivals in both simulated gastric juice and bile salts solution (22.2% and 2.6*10−2%, respectively) than alginate-Ca-EDTA (7.1% and 0%, respectively), indicating a more effective protection of L. acidophilus CGMCC1.2686. The protection efficiency was discussed in relation to the mechanical properties of the microcapsules and the calcium sources used.

A Modified o-Phthalaldehyde Fluorometric Analytical Method for Ultratrace Ammonium in Natural Waters Using EDTA-NaOH as Buffer.

In the existence of appropriate amount of disodium ethylenediaminetetraacetate (EDTA), precipitation would not occur in seawater and other natural waters even if the sample solution was adjusted to strong basicity, and the NH3-OPA-sulfite reaction at the optimal pH range could be used to determine ammonium in natural waters. Based on this, a modified o-phthalaldehyde fluorometric analytical method has been established to determine ultratrace ammonium in natural waters. Experimental parameters, including reagent concentration, pH, reaction time, and effect of EDTA, were optimized throughout the experiments based on univariate experimental design. The results showed that the optimal pH range was between 10.80 and 11.70. EDTA did not obviously affect the fluorometric intensity. The linearity range of the proposed method was 0.032–0.500 µmol/L, 0.250–3.00 µmol/L, and 1.00–20.0 µmol/L at the excitation/emission slit of 3 nm/5 nm, 3 nm/3 nm, and 1.5 nm/1.5 nm, respectively. The method detection limit was 0.0099 µmol/L. Compared to the classical OPA method, the proposed method had the advantage of being more sensitive and could quantify ultratrace ammonium without enrichment.

Copper–tin electrodeposition from an acid solution containing EDTA added

An acid Cu–Sn deposition bath was developed, containing EDTA (disodium ethylenediaminetetraacetate) to sequester the copper(II) and tin(II) ions, forming stable complexes in solution at pH3.4. Voltammetric studies showed that the onset of Cu–Sn codeposition started with reduction of [CuEDTA]2− and [Sn(H2O)6]2+ at potential more negative than −0.90V (first region of deposition). The reduction of [SnEDTA]2− complexes occurs at potential more negative than −1.20V (second region of deposition), leading to Cu–Sn alloys with a higher tin content. The hydrogen evolution reaction (HER) occurs in all range of potential parallel to the Cu–Sn deposition. No nucleation loop was observed in the voltammetric curves for Cu–Sn deposition due to HER. Cu–Sn voltammetric deposition at various sweep rates indicated that the deposition process may be controlled by mass transport and charge transfer in both regions. The Sn content in the potentiostatic Cu–Sn (Ed) change, from ~27.0wt.% to ~60.0wt.%, for a constant composition of deposition bath. Cu–Sn deposit containing 43.6wt.% Sn was obtained from the acid EDTA bath investigated herein. The color of the deposits was reddish (~27.0wt.% Sn) and grayish (~32.0wt.% –~60.0wt.% Sn).Scanning electron microscopy images showed that the deposits produced at −1.03V and −1.30V, for both deposition charge densities (qd), 2.55Ccm−2 and 8.47Ccm−2, were composed of cauliflower-like particles, which increased with qd, and that the deposits obtained at −1.30V were more compact than those formed at −1.03V, for both qd, being this, the main difference between these two types of deposits.X-ray patterns of the deposits formed at Ed=−1.03V, with either qd, using non-grazing incidence, indicated the presence of hcp-CuSn and Cu3Sn phases. However, for Ed=−1.30V were identified the Cu6Sn5 and Cu10Sn3 phases for qd=2.55Ccm−2 and only Cu6Sn5 phase for qd=8.47Ccm−2.

Determination of calcium disodium ethylenediaminetetraacetate (E385) in marketed bottled legumes, artichokes and emulsified sauces by gas chromatography with mass spectrometric detection

An original method to determine the food additive calcium disodium ethylenediaminetetraacetate in bottled food is proposed. The method involves the solid–liquid extraction of a portion of the whole content of legume or artichoke bottles, or the dilution of sauce samples, with water followed by an evaporation step by heating. Finally, ethylenediaminetetraacetic acid is methylated and determined by GC. Recoveries obtained on spiked samples were acceptable (96–108%) with RSDs comprised from 4.3% to 10%. Results suggest that the determination of additive only in the liquid phase of legume or artichoke bottles is not suitable to know its total amount because the additive is distributed between the liquid and solid phases. The contribution of each step of the analytical method to the uncertainty of the measured concentration has been assessed by a “bottom-up” approach, including the heterogeneity of the sample which resulted to be very variable after studying twenty samples.

Dissolution of Soap Scum by Surfactant Part I: Effects of Chelant and Type of Soap Scum

AbstractThe equilibrium solubilities of two model soap scums [calcium stearate and magnesium stearate: Ca(C18)2 and Mg(C18)2] were measured in aqueous solutions containing three different types of surfactants: methyl ester sulfonate (MES) as an anionic; alcohol ethoxylate (EO9) as a nonionic; and dimethyldodecylamine oxide (DDAO) as an amphoteric with and without a chelating agent [disodium ethylenediaminetetraacetate (Na2EDTA)]. The solubility of calcium soap scum was generally higher than that of magnesium soap scum, the exception being some DDAO systems. The use of the DDAO surfactant with the Na2EDTA chelating agent at high pH gives the highest solubilities of both studied soap scums. The soap scum solubility is on the order of 2,000 times that in water at high pH. The DDAO is the most effective surfactant under all conditions. The MES is more effective than the EO9 at low pH with the opposite trend observed at high pH. The synergism from added chelant is generally greater at higher pH and is greatest for DDAO followed by EO9.

Synthesis and characterization of carbon nanotubes/titanium molybdate nanocomposite and assessment of its photocatalytic activity

In this study we have synthesized carbon nanotubes/titanium molybdate nanocomposite (CNT@Tm-NC), the structural, optical, thermal and dielectric properties of the as synthesized CNT@Tm-NC were studied. The XRD analysis ensures that CNT@Tm-NC has the nanostructure structure and confirmed that the titanium molybdate nanoparticles (NPs) were successfully incorporated in the CNT matrix. The thermal analysis (TGA) exhibited an enhanced thermal stability of the CNT@Tm-NC as compare with CNT owing to the strong interaction between the titanium molybdate NPs and CNT matrix. The energy band gaps as calculated through the Tauc relation were found to be higher in the CNT@Tm-NC. The impedance, dielectric constants (ε′, ε′′), dielectric loss (tanδ) and AC conductivity (σac) were studied as the function of frequency, which have been explained by ‘Maxwell Wagner Model’. Moreover, CNT@Tm-NC exhibited the promising photocatalytic activity for the photo-decoloration of the methyl orange (MO) dye under UV light irradiation. Results also showed protection of photo-decoloration of the MO dye by the disodium ethylenediaminetetraacetate dehydrate (EDTA-Na2; C10H14N2Na2O8⋅2H2O) (hole scavenger) and tert-butyl alcohol (C4H10O) (radical scavenger) clearly suggested the implication of reactive oxygen species in the photocatalytic activity of CNT@Tm-NC. It is encouraging to conclude that CNT@Tm-NC bears the potential of it is applications in photocatalysis.

Carbon supported Pd-Pt-Cu nanocatalysts for formic acid electrooxidation: Synthetic screening and componential functions

Carbon supported Pd-Pt-Cu trimetallic nanocatalysts for formic acid oxidation (FAO) are comparatively synthesized via different one-pot liquid-phase chemical reduction routes. Either sodium borohydride or ethylene glycol is employed as the main reducing agent, with the stabilizer opted from disodium ethylenediamine tetraacetate (EDTA), oleylamine, sodium citrate and urea. The trimetallic nanocatalyst synthesized with ethylene glycol and sodium citrate exhibits the most homogeneous nanoparticle dispersion and the highest alloying degree. Pd20Pt1Cu10/C-Cit shows the best electrocatalytic performance among all the tested electrocatalysts. Componential distributions on nanoalloy particles are distinguished through ex situ XPS, CO stripping and in situ ATR-IR measurements on interested nanocatalysts. The cheaper element Cu functions mainly as the “core filler” to expose a Pd and Pt-segregated active surface, and a deliberately controlled small fraction of Pt (versus Pd) on the surface minimizes the undesired dehydration of formic acid. In addition, a weak electronic effect from Cu and Pt may promote FAO on Pd. Surface restructuring with Pt agglomeration and partial Cu dealloying arising from a repeated potential cycling pretreatment degrades the performance of the ternary nanocatalysts.

Recovery of copper (II) absorbed in biomass of Cladosporium cladosporioides

The biosorption process, characterized by the use of biomass for removing metals from aqueous solutions, is an attractive technology using inactive and dead biomasses to remove heavy metals from aqueous solutions in the absence of metabolic activity necessary for intracellular accumulation. The desorption process, which concentrates the metal previously absorbed for possible reuse, is also important. The desorption of copper (Cu) (II) associated with the biomass of Cladosporium cladosporioides (Fres) de Vries was evaluated following the biosorption process (adsorption). Specifically, four eluents were used (all at a concentration 0.1 mol L-1), sulfuric acid, hydrochloric acid, ethylenediaminetetraacetate disodium and calcium chloride, as well as the recovery of Cu (II) desorbed as copper sulfate. After 120 h, 97 % of Cu in solution had been adsorbed. C. cladosporioides can efficiently adsorb Cu (II). Further, 0.1 mol L-1 sulfuric acid was viable and the most efficient for the desorption of the absorbed metal, while ensuring viability of C. cladosporioides after desorption, which is important for the reuse of the biomass in cycles of sorption-desorption.

Pyrolytic synthesis of carbon quantum dots, and their photoluminescence properties

Carbon quantum dots (CQDs) with strong photoluminescence (PL) emission and intriguing upconversion emission property have been prepared by facile and effective pyrolysis of the salt calcium disodium ethylenediamine tetraacetate (EDTA–2Na–Ca·4H2O) at 400 °C. The relative fluorescence quantum yield of the CQDs in aqueous solution reached 66.03 %, which is the highest value yet obtained. Moreover, the CQDs also had a strong upconversion PL property on excitation at 600–750 nm. It is proposed that an anti-Stokes shift is responsible for this upconversion PL emission.

Effect of ethylenediaminetetraacetic disodium dihydrate and sodium nitrite admixtures on steel-rebar corrosion in concrete

This study investigates effect of different concentrations of ethylenediaminetetraacetic disodium dihydrate (EDTA-Na2: C10H14N2Na2O8.2H2O) and sodium nitrite (NaNO2) admixtures, individually or in synergistic/partial NaNO2 replacement model, on the corrosion of concrete steel-rebar in NaCl and in H2SO4 media. Electrochemical monitoring techniques were employed for 48 steel-reinforced concrete samples immersed in the saline/marine and microbial/industrial simulating test environments for 96 days. These test data were subjected to the analyses of the Normal and the Weibull distribution fitting models, for each of which goodness of their fitting the electrochemical test data were studied using the Kolmogorov–Smirnov test statistics. Analysed results showed that EDTA-Na2 admixture concentrations exhibited better inhibition effectiveness, with relatively good effectiveness in their synergistic admixtures, than their equal-mass NaNO2 counterparts in both corrosive environments. Also, post-electrochemical experiment subjection of the concrete samples to testing and analyses of ASTM C39/C39M-03 and ASTM C267-01 showed that use of the optimally inhibiting 8 g EDTA-Na2 (per 2 × 10–3 m3 concrete) culminates in gross reduction in compressive strength of concretes in both test-media. However, lowered EDTA-Na2 concentrations exhibited better strength improvements with high corrosion inhibition in the test environments. These suggest suitability of EDTA-Na2 as an environmental-friendly NaNO2 alternative for inhibiting steel-rebar corrosion in saline/marine and microbial/industrial environments.

Synthesis and characterization of structural, optical, thermal and dielectric properties of polyaniline/CoFe2O4 nanocomposites with special reference to photocatalytic activity

In this study we have synthesized polyaniline/CoFe2O4 nanocomposites (PANI@CFs) by in situ polymerization method with different amounts of the CoFe2O4 nanoparticles NPs (CF–NPs) (0.5 g and 1.0 g). The structural optical, thermal and dielectric properties of the as synthesized PANI@CFs were studied. The XRD analysis ensures that CF–NPs have a single phase spinel structure. The XRD and EDAX results confirmed that the CF-NPs were successfully incorporated in the PANI matrix. The crystalline size analysis revealed that the size increased with increasing CF–NPs amount in the PANI@CFs, because of the aggregation effect. TGA exhibited an enhanced thermal stability of the PANI@CFs as compare with PANI owing to the strong interaction between the CF–NPs and polymer matrix. The energy band gaps as calculated through the Tauc relation were found to be gradually higher with the increasing the amount of CF–NPs in PANI@CFs. The dielectric constants (ε′, ε″), dielectric loss (tanδ) and AC conductivity (σac) were studied as the function of frequency and composition, which have been explained by ‘Maxwell Wagner Model’. The high dielectric constant and ac conductivity were observed of PANI@CFs than PANI. Moreover, PANI@CF 1:2 exhibited the promising photocatalytic activity for the photo-decoloration of the methyl orange (MO) dye under UV light irradiation. Results also showed protection of photo-decoloration of the MO dye by the disodium ethylenediaminetetraacetate dehydrate (EDTA-Na2; C10H14N2Na2O8⋅2H2O) (hole scavenger) and tert-butyl alcohol (C4H10O) (radical scavenger) clearly suggested the implication of reactive oxygen species (ROS) in the photocatalytic activity of PANI@CF 1:2. It is encouraging to conclude that PANI@CF bears the potential of its applications in photocatalysis.

Electroless Deposition of Highly Solderable Fe-Ni Films

The simultaneous electroless-deposition of Fe and Ni is challenging because Fe has a more negative standard reduction potential than Ni. In this study, FeNiP electroless deposits with Fe content up to 97 at.% were prepared by complexing with disodium ethylene diamine tetraacetate (EDTA-2Na). The addition of ETDA-2Na complexing agent effectively reduced the difference in the electrode potential between Ni and Fe from 0.21 V to 0.156 V, resulting in Fe-Ni depositions with very high Fe concentrations. The iron concentrations of deposited films were systematically investigated as functions of bath temperature, concentrations of EDTA-2Na and DTPA, mole ratio of Fe2+/Ni2+ and contents of NH3•H2O in the plating bath. The solderability of electroless FeNiP deposits with Sn and SnAgCu solders was found to increase with the iron content in the deposits from 0 at.% to 85 at.%, and to be better than that of the electroless NiP.

Application of Electroless Fe−42Ni(P) Film for Under-bump Metallization on Solder Joint

Because Fe has a more negative standard reduction potential than Ni, the simultaneous electroless deposition of Fe and Ni is difficult. In this study, Fe–42Ni(P) electroless deposit was prepared by using disodium ethylene diamine tetraacetate (ETDA-2Na) as complexing agent to reduce the difference in the electrode potential between Ni 2+ and Fe 2+ . The solderability and the interfacial reaction between Fe−42Ni(P) alloy and Sn were investigated. It was found that the electroless Fe−42Ni(P) alloy has excellent wettability with Sn. Moreover, the interfacial reaction rate between Fe−42Ni(P) and Sn is very slow. These results suggest that Fe–42Ni(P) alloy may become an attractive under-bump metallization (UBM).

Preparation and Release Behavior of Polyelectrolyte Microcapsules

Hybrid calcium carbonate (CaCO3)/poly(styrene sulfonate) (PSS) particle, as a template, was synthesized using colloidal crystallization with the presence of nitrate tetrahydrate (Ca(NO3)2•4H2O), sodium carbonate (Na2CO3) and PSS. Microcapsule was prepared by template-assisted layer-by-layer (LbL) technology in solutions of two oppositely charged polyelectrolytes, poly(styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) alternately, followed by dissolving the template with disodium ethylenediaminetetraacetate (EDTA). The release behavior of rhodamine B (RhB) from the microcapsules was examined and the rates of release at different pH were studied.

Sacrificial PSS-doped CaCO3 templates to prepare chitosan capsules and their deformation under bulk pressure

To prepare microcapsules composed of chitosan (CS), a templating method is developed using poly(styrene sulfonate) (PSS)-doped porous calcium carbonate (CaCO3) templates as sacrificial templates. First, CS is absorbed onto PSS-doped porous CaCO3 templates, and then the absorbed CS is covalently cross-linked with each other by using glutaraldehyde. Porous CaCO3 templates are dissolved with disodium ethylenediaminetetraacetate dihydrate and the resultant CS capsules ranged from 2 to 5 μm in diameter. Nitrogen adsorption–desorption analysis are applied to characterize the porous CaCO3 templates, the BET surface area and total pore volume are 220 m2/g and 0.36 cm3/g, respectively. Field-emission scanning electron microscopy and transmission electron microscopy were used to characterize the CS capsules morphology. Confocal laser scanning microscopy images reveal that the capsules have been labeled with green fluorescein isothiocyanate. The gradual deformation of capsule in response to bulk osmotic pressure created by CS solutions has also been discussed.

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.

Photochemical Hydrogen Production from Water Using Three-Dimensional Zn-Pd Metal-Organic Frameworks

A Zn-Pd heterometallic metal-organic framework (MOF) based on 3,5-pyridine-dicarboxylic acid (H2-pydc), namely [Zn2(H2O)3{PdCl2(pydc)2}]n (Zn-Pd-2) was successfully synthesized by a slow diffusion method and characterized by single-crystal X-ray diffraction, CHN elemental analysis, FT-IR spectroscopy, thermogravimetric (TG) analysis and N2 gas adsorption measurement. The single-crystal X-ray analysis revealed that the framework morphology of Zn-Pd-2 is as same as that of [Zn2(DMF)3{PtCl2(pydc)2}]n. The Zn-Pd-2 was found to be an effective catalytic performance for the photochemical reduction of water in a well-known photo-system made up of [Ru(bpy)3Cl2] (bpy = 2,2'-bipyridine), MV(2+) (methyl-viologen) and Na2 EDTA (Disodium ethylenediaminetetraacetate); 20.2 turnover based on Zn-Pd-2 was achieved at 4 h irradiation.

Determination of Disodium Ethylene Diaminetetraacetate in SamplesBased on Ion Chromatography with In Guard H Column

A method for the determination of EDTA was developed and validated based on ion chromatography with suppressed conductimetric detection and anion exchange column.The pre-concentration of EDTA was obtained on In guard H by using pump and ten ports valve,then the optimization separation condition was performed on a IonPac AS22(250 mm×4.0 mm) using 4.5 mmol/L carbonate and 1.4 mmol/L bicarbonate buffer solution with 18% acetonitrile as the mobile phase with Isocratic elution.Good resolution was achieved from commonly coexisting anions and organic acid.The interference of different metal cations(Ca2+,Mg2+,Cu2+,Zn2+ and Fe3+) and the increase of molar ratio were also examined.The ion chromatographic method was applied for the assay of EDTA in contact lens care solutions、salad and canned foods with simple treatment.The linear range of EDTA was 0.6-50 mg/kg.The recovery of EDTA was about 91.2%-97.0%.

Facile route fabrication of nano-Ni core mesoporous-silica shell particles with high catalytic activity towards 4-nitrophenol reduction

A facile, environmentally friendly synthetic route was developed to prepare nano-Ni core mesoporous-silica shell particles. Ethylenediaminetetraacetic disodium salt (EDTA) was the chelating agent and thus controlled the nucleation rate of the nano-Ni core. In this work, EDTA was used to regulate the reduction rate of nickel acetate. Thereby, by varying the amount of EDTA utilized in reaction medium, the size of nano-Ni can be readily controlled in the range of 40–80 nm. The mesoporous silica shell was fabricated by the Stober method. The nano-Ni core mesoporous-silica shell particles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). UV spectrophotometry (UV/vis) was used to analyse the growth mechanism of the nano-Ni cores. The as-synthesized nano-Ni core mesoporous silica shell particles were found to show a good catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol in the presence of an excess amount of NaBH4. The magnetic properties, catalytic mechanism and the possibility of reusability were also investigated.