Ethylenediaminetetraacetic Research Articles

Capacity of Lemna gibba L. (Duckweed) for Uranium and Arsenic Phytoremediation in Mine Tailing Waters

ABSTRACT The potential of Lemna gibba L. to clean uranium and arsenic contamination from mine surface waters was investigated in wetlands of two former uranium mines in eastern Germany and in laboratory hydroponic culture. Water and plants were sampled and L. gibba growth and yield were monitored in tailing ponds from the field study sites. Contaminant accumulation, growth and yield experiments were conducted in the laboratory using synthetic tailing water. Mean background concentrations of the surface waters were 186.0 ± 81.2 μg l−1 uranium and 47.0 ± 21.3 μg l−1 arsenic in Site one and 293.7 ± 121.3 μg l−1 uranium and 41.37 ± 24.7 μg l−1 arsenic in Site two. The initial concentration of both uranium and arsenic in the culture solutions was 100 μg l−1. The plant samples were either not leached, leached with deionized H2O or ethylenediaminetetracetic (EDTA). The results revealed high bioaccumulation coefficients for both uranium and arsenic. Uranium and arsenic content of L. gibba dry biomass of the field samples were as follows: nonleached samples > deionized H2O leached (insignificant ANOVA p = 0.05) > EDTA leached. The difference in both arsenic and uranium enrichment were significantly high between the nonleached and the other two lead samples tested at ANOVA p > 0.001. Estimated mean L. gibba density in surface water was 85,344.8 ± 1843.4 fronds m−2 (∼1319.7 g m−2). The maximum specific growth rate was 0.47 ± 0.2 d−1, which exceeded reported specific growth rates for L. gibba in the literature. Average yield was estimated at 20.2 ± 6.7 g m−2 d−1, giving approximately 73.6 ± 21.4 t ha−1 y−1 as the annual yield. The highest accumulations observed were 896.9 ± 203.8 mg kg−1 uranium and 1021.7 ± 250.8 mg kg−1 arsenic dry biomass for a 21-d test period in the laboratory steady-state experiments. The potential extractions from surface waters with L. gibba L. were estimated to be 662.7 kg uranium ha−1 yr−1 and 751.9 kg arsenic ha−1 yr−1 under the above conditions.

Raman scattering from single Ag aggregates in presence of EDTA

We report on Surface Enhanced Raman Scattering (SERS) activity of silver colloids prepared by a radiolytic method followed by a chemical development by EthyleneDiAmineTetraAcetic (EDTA) acid. On these colloids, in presence of Rhodamine 6G and of EDTA, we have observed Single Molecule SERS spectra. We show that the spectra observed on single silver aggregates in presence of EDTA evidence a (photo)oxidative character of sites that exhibit a giant SERS enhancement.

Effect of polyolefin-coated EDTA (Ethylenediamine Tetraacetic Acid)-K2SO4 1 on the growth of Italian ryegrass and red clover in sandy soil

Granulated ethylenediamine tetraacetic acid disodium salt (EDTA-2Na) was coated with polyolefin resin to control its release into soil. The granules contained 15.7% EDTA and 71.0% K2S04 on a dry-weight basis and it took 10 weeks for the granules to release the first half of EDTA. Italian ryegrass (Lolium multiflorum Lam.) and red clover (Trifolium pratense L.) were grown in sandy soil with AIPO4, FePO4, or CaHPO4 at a concentration of 0,2 g P2O5 pot−1 (4 kg soil) with and without coated EDTA. Plant growth was significantly enhanced due to the increase in P and K uptake, although, powdery EDTA at the same dose impaired the growth.

Comparative study of nitrilo triacetic acid (NTA) and EDTA as formulation constituents for the chemical decontamination of primary coolant systems of nuclear power plants

Radiation field reduction in the Primary Heat Transport (PHT) system of water cooled reactors can be achieved by `Dilute Chemical Decontamination (DCD) process' operated in regenerative mode. This process uses a mixture of dilute amino carboxylic/ carboxylic acids and reducing/ oxidizing agents to remove the oxide film and the activity deposited on the out-of-core surfaces of nuclear power reactors. Ethylene Diamine Tetra Acetic Acid (EDTA) is normally used as the main chelating agent in the chemical formulations employed. Detailed studies indicated that Nitrilo Triacetic Acid (NTA) instead of EDTA could be used as the main chelating agent. Consequently, a new chemical formulation was evolved and its oxide dissolution characteristics, corrosion compatibility of structural materials, pick-up on ion exchange resins, ion exchange capabilities, radiation stability have been evaluated and compared with the EDTA based formulation. Some studies have been carried out in heavy water as the decontamination of primary coolant system of Pressurized Heavy Water Reactors (PHWRs) is carried out in heavy water medium. From these studies, it has been concluded that NTA as a constituent of decontamination formulation has many advantages over EDTA for the chemical decontamination of primary coolant systems of PHWRs. The new formulation can also be applied to stainless steel systems such as PWRs and BWRs as a reducing formulation followed by an oxidation step.

HPLC in the analysis of peptide metabolism.

AbstractBioactive peptides are generally synthesized within large precursor molecules, from which the active moiety must be enzymatically excised by one or more specific peptidases (1). For most peptides, this processing occurs intracellularly, within the secretory pathway, but cosecretory or extracellular processing can also occur. Peptidases also play a critical role in the termination of peptide signals, via cleavage to inactive fragments (2,3). The characterization of the peptidases involved in the generation and metabolism of peptides is thus of critical importance to the understanding of the physiology of specific peptide hormones and neurotransmitters.KeywordsMembrane FractionHPLC Grade WaterMass Spectral AnalysisNeutral EndopeptidaseDisodium Ethylene Diamine Tetraacetic AcidThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Anodic oxidation with doped diamond electrodes: a new advanced oxidation process

Boron-doped diamond anodes allow to directly produce OH radicals from water electrolysis with very high current efficiencies. This has been explained by the very high overvoltage for oxygen production and many other anodic electrode processes on diamond anodes. Additionally, the boron-doped diamond electrodes exhibit a high mechanical and chemical stability. Anodic oxidation with diamond anodes is a new advanced oxidation process (AOP) with many advantages compared to other known chemical and photochemical AOPs. The present work reports on the use of diamond anodes for the chemical oxygen demand (COD) removal from several industrial wastewaters and from two synthetic wastewaters with malic acid and ethylenediaminetetraacetic (EDTA) acid. Current efficiencies for the COD removal between 85 and 100% have been found. The formation and subsequent removal of by-products of the COD oxidation has been investigated for the first time. Economical considerations of this new AOP are included.

Controlling factors affecting the stability and rate of electroless copper plating

The purpose of this article is to focus on the electroless copper plating step from tartarate or ethylenediaminetetraacetic (EDTA) baths used in through hole plating (THP) of printed circuit boards (PCBs). The effect of bath operating conditions (temperature, pH and agitation) and bath additives (pyridine, cytosine, thiourea, benzotriazole (BT) and 2-mercaptobenzothiozole (2MBT)) on plating rate, bath stability, morphology and etching rate of the coating has been studied. It has been found that all the organic additives studied except thiourea not only stabilize electroless copper baths but also enhance the plating rate from 1.1 to 1.8 mg/(cm 2 h) in the tartarate bath at 30 °C and from 5.4 to 10.5 mg/(cm 2 h) in the EDTA bath at 50 °C. Mild air agitation increases the bath stability 20 times that of bath without aeration. The additives were found to modify the crystal structure with the production of small grain size, dense, tightly adherent and etching resistant copper deposit.

Preparation of metal‐containing protein fibers and their antimicrobial properties

AbstractBombyx mori silk, Antheraea pernyi silk, and wool fibers were chemically modified by treatment with tannic acid (TA) or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. Kinetics of TA loading or acylation with EDTA‐dianhydride varied from fiber to fiber. B. mori silk and wool displayed the highest weight gains with TA and EDTA‐dianhydride, respectively. The uptake of different metal ions (Ag+, Cu2+, Co2+) by protein fibers, either untreated or chemically modified, was studied as a function of weight gain and pH of the aqueous metal solution. Below pH 7, absorption of metal ions by untreated and TA‐treated fibers was negligible. Acylation with EDTA‐dianhydride enabled protein fibers to absorb and bind significant amounts of metal ions in the acidic and neutral pH range. The levels of metal desorption at acidic pH depended on the fiber‐metal combination. Untreated protein fibers usually displayed the lowest stability of the metal complex. Metal complexes with protein fibers exhibited prominent antimicrobial activity against the plant pathogen Cornebacterium. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 638–644, 2003

The Ion Effect on Dewaterability of Alumina-Metal EDTA System

The specific ion effects are observed in the alumina-metal EDTA(Ethylene Diamine Tetraacetic Acid) system. These effects seem to be associated with the fluidity of the metal ion in the complex. A consideration of the order of adsorption of the complexes on alumina indicates that a specific ion effect also affects the stability of the system. It is clear that EDTA and its heavy metal complexes have a significant effect on the dewaterability of alumina. These effects are not well represented by zeta potential measurements, especially for EDTA alone. With the nonspeciating complexes, though, the maximum permeability is predicted by the pH<TEX>$\_$</TEX>zpc/ from zeta potential measurements. At other pH value, the refiltration rate is better predicted by the state of coagulation as measured by log W.

Binding of Co(II) and Cu(II) cations to chemically modified wool fibres: an IR investigation

Wool fibres were modified by treatment with tannic acid (TA) solution or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. The unmodified and modified fibres were subsequently treated with Cu 2+ and Co 2+ solutions, at alkaline pH, and analysed by Attenuated Total Reflectance, ATR/IR spectroscopy to evaluate the changes induced in the structure of the fibre by metal binding. The spectral changes were correlated to metal adsorption results obtained by Inductive Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The IR results were discussed in relation to our previous findings on the metal binding mode of Bombyx mori and Tussah silk fibres; the changes observed in the spectra were explained by considering the different affinity of the fibres for the modifying reagent and the amount of the metal absorbed. More relevant spectral changes were observed upon Cu 2+ complexation rather than Co 2+ complexation, according to the metal absorption results. The most relevant changes were observed for the EDTA-modified wool sample treated with Cu 2+, according to the higher affinity of wool for EDTA. The IR spectra were quantitatively evaluated by the intensity ratio between the Amide I and Amide II bands (I AmideI/I AmideII) and its trend as a function of metal absorption was reported. The present investigation demonstrated that the interaction between fibre and metal and the subsequent fibre modification depend on the chemical nature of the fibre, the metal cation and the modifying reagent.

IR study on the binding mode of metal cations to chemically modified Bombyx mori and Tussah silk fibres

Bombyx mori ( B. mori) and Tussah ( Antheraea pernyi) silk fibres were modified by treatment with tannic acid (TA) or ethylenediaminetetraacetic (EDTA) dianhydride, subsequently treated with Cu 2+ and Co 2+ solutions, at alkaline pH, and analysed by attenuated total reflectance/infrared spectroscopy to evaluate the changes induced in their structure by metal binding. The spectral changes were correlated to metal binding results obtained by inductive coupled plasma-atomic emission spectrometry. Upon Co 2+ complexation, the spectra of all the B. mori and Tussah silk samples showed a decrease in intensity of the Amide I band with a trend related to the metal uptake. The most relevant changes in the whole spectra were observed for the EDTA- and TA-modified samples in the case of B. mori and Tussah silks, respectively. Upon Cu 2+ complexation, the decrease in intensity of the Amide I band follows the trend of the metal uptake only in the case of Tussah silk. Moreover, the most relevant changes with respect to the untreated sample were observed for the TA-modified B. mori silk sample. The spectral changes were explained by considering the different affinities of the fibres for the modifying reagent, the amount of the metal bound and the relative stability of the complexes formed.

Role of organic acids in enhancing the desorption and uptake of weathered p,p′-DDE by Cucurbita pepo

Experiments were conducted to assess the effect of seven organic acids [succinic, tartaric, malic, malonic, oxalic, citric, ethylenediaminetetraacetic (EDTA)] over a concentration range of two orders of magnitude (0.001–0.10 M) on the abiotic desorption of weathered p,p′-DDE and the extraction of polyvalent inorganic ions from soil. At 0.05 M all organic acids significantly increased contaminant desorption by 19–80%. Organic acids also increased the aqueous concentration of eight inorganic constituents extracted from soil, with at least a six-fold increase in the release of Al, Fe, Mn, and P at 0.001 M. Zucchini seedlings grown for 28 d in soil containing weathered p,p′-DDE (300 ng/g, dry weight) were periodically amended with distilled water, citric or oxalic acids (0.01 M). Plants receiving water removed 1.7% of the p,p′-DDE from the soil. Seedlings amended with citric or oxalic acids removed 2.1 and 1.9% of the contaminant, respectively, and contained up to 66% more contaminant in the shoot system than unamended vegetation. A second crop of untreated (distilled water) zucchini in the same soil removed more contaminant than the first crop (2.5%), although the addition of organic acids did not further enhance contaminant uptake. The data indicate that the addition of low molecular weight organic acids causes the partial dissolution of the soil structure through the chelation of inorganic structural ions, potentially enhancing bioavailability and having implications for the phytoremediation of persistent organic pollutants in soil.

Binding of metal cations to chemically modified wool and antimicrobial properties of the wool–metal complexes

AbstractWool was modified by treatment with tannic acid (TA) or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. Kinetics of modification with TA and acylation with EDTA–dianhydride was investigated as a function of the reaction time. Wool displayed a higher breaking load and lower elongation at break as the degree of acylation increased. The absorption of metal cations (Ag+, Cu2+) by untreated and chemically modified wool was studied as a function of the kind of modifying agent, weight gain, and pH of the metal solution. Absorption of Ag+ and Cu2+ at alkaline pH increased with increasing weight gain of both TA and EDTA–dianhydride. The absorption of metal cations by untreated and TA‐treated wool below pH 7 was negligible. Acylation with EDTA–dianhydride enabled wool to absorb and bind significant amounts of metal cations at acidic and neutral pHs. The wool–Ag complexes exhibited low levels of metal desorption at acidic pH, irrespective of chemical modification. Higher levels of metal desorption were shown by wool–Cu and wool–EDTA–Cu complexes. Wool–Ag complexes exhibited prominent antimicrobial activity against Cornebacterium and E. coli. © 2001 John Wiley &amp; Sons, Inc. J Appl Polym Sci 82: 3513–3519, 2001

Absorption of metal cations by modifiedB. mori silk and preparation of fabrics with antimicrobial activity

Silk fabrics were modified by treatment with tannic acid (TA) solution or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. Kinetics of modification with TA and acylation with EDTA–dianhydride was investigated. The physico-mechanical properties of silk fabrics acylated with EDTA–dianhydride remained unchanged regardless of chemical modification. The absorption of metal cations (Ag+, Cu2+) by untreated and modified silk fabrics was studied as a function of the kind of modifying agent, weight gain, and pH of the metal solution. The absorption of Cu2+ at alkaline pH was not significantly influenced by chemical modification of the silk substrate. The absorption of Ag+ by acylated silk remained at a level as low as untreated silk, while was enhanced by TA. The higher the content of TA, the higher the absorption of Ag+. With respect to the pH of the metal solution, the acylation with EDTA–dianhydride enabled silk to absorb and bind metal cations even in the acidic and neutral pH range, where tannic acid had no effect. Medium to high levels of metal desorption were exhibited by untreated and modified silk fabrics towards the metal cations, with the only exception of the silk–tannic acid–Ag complex, which displayed an extraordinary stability. All metal-containing silks exhibited significant antibacterial activity. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 297–303, 2001

Suppression of adhesion and invasion of hepatoma cells in culture by tea compounds through antioxidative activity

To determine the actions of tea components on the invasion of a rat ascites hepatoma cell line of AH109A and to understand their modes of action, the cancer cells were co-cultured with a rat mesentery-derived mesothelial cell monolayer in the presence of tea components. The synergistic effects of (−)-epicatechin (EC) with (−)-epigallocatechin gallate (EGCG) on AH109A invasion were demonstrated. Further study showed that 10 μM of EGCG or theaflavins, or 2.5 μM of ethylenediaminetetra-acetic (EDTA) entirely abolished the increase in AH109A adhesion and invasion stimulated by reactive oxygen species (ROS) from the hypoxanthine–xanthine oxidase system. Our results suggest that OH −- and other ROS-scavenging activity of EGCG and theaflavins may be responsible for the inhibition of OH −- and related ROS-potentiated AH109A adhesion and invasion to the cultured rat mesothelial cell monolayer.

Synthesis of All Distinct α-Methyl-Substituted Isomers of Amino Bis(2,2′-Ethanoic Acid) Diethyl Ester and Ethylene Diamine Tetraacetic Acid Tetraethyl Ester Scaffolds

The syntheses of three dialkylated and six tetraalkylated ethylene diamine tetraacetic acid tetraesters is described. The dialkylated derivatives were synthesized by a convergent non-racemizing route to yield three enantiomerically and diastereomerically pure tetraesters ( SS)- 3a , ( RR)- 3b and ( R ∗ S ∗)- 3c in 55–57% yields from alanine ethyl ester 1. Enantiomerically and diastereomerically pure tetraalkylated derivatives ( SSSS)- 8a , ( RRRR)- 8b , (2 R ∗,2′ S ∗,2″ R ∗,2‴ S ∗)- 8c , (2 R ∗,2′ R ∗,2″ S ∗,2‴ S ∗)- 8d , (2 R,2′ R,2″ R,2‴ S)- 8e and (2 S,2′ S,2″ S,2‴ R)- 8f were synthesized in two to five steps and 22–49% overall yields from alanine ethyl ester 1.

Outer-sphere adsorption of Pb(II)EDTA on goethite

Fourier transform infrared (FTIR) and extended X-ray absorption fine structure (EXAPS) spectroscopic measurements were performed on Pb(II)ethylenediaminetetraacetic (EDTA) adsorbed on goethite as a function of pH (4–6), Pb(II)EDTA concentration (0.11–72 μM), and ionic strength (16 μM–0.5 M). FTIR measurements show no evidence for carboxylate-Fe(III) bonding or protonation of EDTA at Pb:EDTA = 1:1. Both FTIR and EXAFS spectroscopic measurements suggest that EDTA acts as a hexadentate ligand, with all four of its carboxylate and both of its amine groups bonded to Pb(II). No evidence was observed for inner-sphere Pb(II)-goethite bonding at Pb:EDTA = 1:1. Hence, the adsorbed complexes should have composition Pb(II)EDTA2−. Because substantial uptake of PbEDTA(II)2− occurred in the samples, we interpret that Pb(II)EDTA2− adsorbed as outer-sphere complexes and/or as complexes that lose part of their solvation shells and hydrogen bond directly to goethite surface sites. We propose the term “hydration-sphere” for the latter type of complexes because they should occupy space in the primary hydration spheres of goethite surface functional groups and to distinguish this mode of sorption from common structural definitions of inner- and outer-sphere complexes. The lack of evidence for inner-sphere EDTA-Fe(III) bonding suggests that previously proposed metal/ligand-promoted dissolution mechanisms should be modified, specifically to account for the presence of outer-sphere precursor species.

Investigating fine galena recovery problems in the lead circuit of Mount Isa Mines Lead/Zinc Concentrator part 1: Grinding media effects

A plant survey was carried out on the lead secondary rougher and scavenger banks of the Lead/Zinc Concentrator of Mount Isa Mines Limited. Sizing analysis of the survey samples demonstrated that a major limiting factor to overall lead recovery in this section of the plant was the diminished recovery of the fine galena in the minus 5 microns particle size fraction. Batch flotation experiments were carried out on a plant sample of lead secondary rougher feed and a sample of rod mill feed ore. Mineral recovery-size data for these tests showed similar fine galena flotation behaviour to that observed in the plant. Increased collector addition did not improve either the maximum recovery or the flotation rate constant of the fine galena but did reduce the selectivity of galena against sphalerite. Changing of the grinding media used for the ore sample from a high carbon steel to a high chromium alloy steel resulted in a significant increase in the maximum recovery and flotation rate constant of the fine galena. EDTA (ethylene diaminetetraacetic) extractable iron measured for the high carbon steel media were similar in magnitude to those measured within the plant and were higher than those measured for the high chromium alloy steel media. The increased surface concentration of hydrophilic layers of oxidised iron species on the fine galena was a likely reason for their diminished flotation behaviour both in the laboratory and in the plant.

Binuclear Copper(II) Chelates of Amide-Based Cyclophanes.

A chelating cyclophane has been synthesized by cyclocondensation of two ethylenediaminetetraacetic (EDTA) units with two p-phenylenediamine units: the resulting cyclophane is 2,9,18,25-tetraoxo-4,7,20,23-tetrakis(carboxymethyl)-1,4,7,10,17,20,23,26-octaaza[10.10]paracyclophane, abbreviated as (bis-edtapdn)H(4). Cyclocondensation of two EDTA and two 1,5-diaminonaphthalene units has given the naphthalenophane, 2,9,22,29-tetraoxo-4,7,24,27-tetrakis(carboxymethyl)-1,4,7,10,21,24,27,30-octaaza[10.10](1,5)naphthalenophane, (bis-edtanap)H(4). Studies of electronic and EPR spectra have been carried out on the binuclear Cu(2+) complexes of these new ligands and of related chelating cyclophanes, 2,9,25,32-tetraoxo-4,7,27,30-tetrakis(carboxymethyl)-1,4,7,10,24,27,30,33-octaaza[10.1.10.1]paracyclophane, abbreviated as (bis-edtabpm)H(4), and 2,9,25,32-tetraoxo-4,7,27,30-tetrakis(carboxymethyl)-1,4,7,10,24,27,30,33-octaaza-17,40-dioxa[10.1.10.1]paracyclophane, abbreviated as (bis-edtabpe)H(4). Common features of these chelating cyclophanes are as follows: (1) amino, amide, and pendant carboxymethyl donor groups are substituents in the cyclophane ring, and (2) the amide groups are directly bound to the aromatic groups. These ligands formed neutral binuclear Cu(2+) chelates [Cu(2)L](0) that are water-insoluble. In alkaline solutions, these Cu(2+) complexes were converted to anionic chelates [Cu(2)(LH(-)(4))](4)(-) in which deprotonated amide nitrogens coordinated Cu(2+) ions. These anionic metal chelates of (bis-edtapdn)H(4), (bis-edtabpm)H(4), and (bis-edtabpe)H(4) exhibited three pi-pi transition bands in the spectral range 240-340 nm, in contrast to the uncoordinated cyclophanes, which showed a single band in this spectral range. The unusual pi-pi transition spectra of the [Cu(2)(LH(-)(4))](4)(-) complexes originate from the combined effect of metal-ligand charge transfer and proximity of the pi systems. The absorption and emission spectra of (bis-edtanap)H(4) were also influenced by coordination with copper. The EPR spectrum of [Cu(2)(bis-edtanapH(-)(4))](4)(-) in a methanol glass matrix showed a hyperfine structure due to the spin exchange between two Cu(2+) ions. These unusual spectral and magnetic properties arise from the strong coordination between Cu(2+) ions and deprotonated amide nitrogens that are bound to the pi systems.

Speciation of metals in different oxidation states by capillary electrophoresis using pre-capillary complexation with complexones

Ethylenediaminetetraacetic (EDTA), cyclohexane-1,2-diaminetetraacetic (CDTA) and diethylenetriaminepentaacetic (DTPA) acids were investigated and compared as complexing agents for the speciation of chromium(VI/III), vanadium(V/IV) and iron(III/II) ions by capillary electrophoresis. The chromium(III) was selectively chelated with DTPA in order to impart a negative charge and similar mobility to both the chromium(III) and chromium(VI) species. The best complexing agent for the determination of vanadium species was found to be EDTA. The addition of an excess of EDTA, CDTA or DTPA to the solution containing both iron species causes the rapid and complete oxidation of iron(II) into iron(III) by ambient oxygen. Therefore for the simultaneous determination of both iron species two different complexing agents were used: o-phenanthroline for Fe2+ and CDTA for Fe3+. Detection was carried out by direct UV absorption depending on the properties of the formed complexes. For all species studied the calibration graphs were linear over at least two orders of magnitude of concentration. The detection limits were in the range from 1 × 10–6 mol l–1 for FeII to 83 10–6 mol l–1 for CrVI. Application of the method to the speciation of metal ions in real samples is also demonstrated.