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Enrofloxacin (ENR) is widely used in aquaculture due to its broad-spectrum activity against a large number of pathogenic bacteria. However, ENR exhibits strong adsorption and a low biodegradation rate in the environment. This study proposes a new method for degrading ENR, which combines dielectric barrier discharge (DBD) with advanced oxidation of peroxymonosulfate (PMS, HSO5−) and the use of nitrilotriacetic acid (NTA) combined with Fe(III) activator to improve reaction efficiency. The effects on the degradation efficiency were experimentally investigated by adjusting the internal process parameters and adding coexisting substances. The ESR and free radical scavenging experiments showed that both hydroxyl and sulfate radicals contributed to the degradation of the pollutant ENR. Based on the identified intermediates, and three possible degradation pathways were suggested. And the intermediates were less harmful. In conclusion, the Fe(III)-NTA/PMS/DBD system may be an efficient, environmentally friendly and new technology with development potential. [ABSTRACT FROM AUTHOR]

AbstractIn this paper, an excellent foaming formula for natural gas well deliquification was developed, which was based on the synthesized dodecyl ethylethanolamine (DEEA), commercially obtained cocamidopropyl betaine (CAPB) and sodium lauryl glutamate (SLG). The foaming properties and liquid unloading properties were studied, which showed that the optimal molar ratio of DEEA/CAPB/SLG ternary complex turned out to be 14:21:15. At a total concentration of 15 mM in the liquid phase, the optimal DEEA/CAPB/SLG mixture exhibited excellent foaming and liquid unloading capability at various conditions of methanol, condensate oil and salts contents and temperatures. At the methanol content of 45%, the foaming efficiency and liquid unloading efficiency of the DEEA/CAPB/SLG mixture were measured to be 100% and 25.5 ± 2.2%, respectively. When the condensate oil content was 10–30%, the liquid unloading efficiency ranged from 18.0 ± 2.1% to 25.0 ± 2.5%, which was much higher than that (8.3 ± 0.9%) obtained without condensate. The presence of salts retarded the performance of the DEEA/CAPB/SLG mixture, however, the addition of a chelating agent, trisodium nitrilotriacetic acid (NTA), to DEEA/CAPB/SLG could enhance the foaming efficiency and unloading performance at a salinity level of up to 41 × 104 mg/L, which might be the highest salt-resistant level of the gas well foaming mixture. The introduction of 10% methanol exhibited a positive effect on the DEEA/CAPB/SLG mixture’s foaming and liquid unloading performance against temperature (up to 90 °C). At 90 °C, the DEEA/CAPB/SLG foam could remove almost all the liquid from the column. [ABSTRACT FROM AUTHOR]

This study focused to enhance the cadmium (Cd) phytoextraction efficiency in Solanum nigrum by applying four biodegradable chelants (10 mM)-ethylene glycol tetraacetic acid (EGTA), ethylenediamine disuccinate (EDDS), nitrilotriacetic acid (NTA), and citric acid (CA), when grown in Cd-spiked soil (12 and 48 mg kg−1). Plant height, dry biomass, photosynthetic traits, and metal accumulation varied significantly with Cd and chelant treatments. Cadmium-toxicity resulted in reduction of plant growth and photosynthetic physiology, whereas chelant supplementation alleviated the toxic effect of Cd and increased its accumulation. Tolerance index value increased with addition of chelants in the order: EGTA (1.57–1.63) >EDDS (1.39–1.58) >NTA (1.14–1.50) >CA (1–1.22) compared with Cd (0.46–1.08). Transfer coefficient of root increased with supplementation of EGTA (3.40–3.85), EDDS (3.10–3.40), NTA (2.60–2.90), and CA (1.85–2.29), over Cd-alone (1.61–1.63). Similarly, translocation factor was also increased upon addition of EGTA (0.52–0.73), EDDS (0.35–0.81), NTA (0.38–0.75), and CA (0.53–0.54), compared with Cd-alone (0.36–0.59). Maximum Cd removal (67.67% at Cd12 and 36.05% at Cd48) was observed with supplementation of EGTA. The study concludes that the supplementation of EGTA and EDDS with S. nigrum can be employed as an efficient and environmentally safe technique for reclamation of Cd-contaminated soils. Apart from the selection of a good hyperaccumulator, the choice of chelant (biodegradable/non-biodegradable) is an important aspect for the successful phytoextraction of metals from contaminated soil. We reported for the first time the potential of ethylene glycol tetraacetic acid (EGTA; a biodegradable chelant) in enhancing Cd phytoextraction by Solanum nigrum. Comparative appraisal of metal extraction efficiency of biodegradable chelants at low (12 mg kg−1) and high (48 mg kg−1) Cd dose depicted that EGTA performed better than EDDS, NTA, and CA (other biodegradable chelants). EGTA supplementation did not induce toxicity in plants; rather it improved metal accumulation, morphology, and photosynthetic physiology. [ABSTRACT FROM AUTHOR]

A new supramolecular metal-organic complex, [(DMA)+{Fe(IDA)2}-] (where H2IDA = iminodiacetic acid and DMA = dimethylammonium cation) (1), has been synthesized solvothermally at 90 °C from reaction of ferric(III) chloride hexahydrate with nitrilotriacetic acid (H3NTA) in stoichiometric ratio. The complex was characterized by single crystal X-ray diffraction (SCXRD) along with spectroscopic analyses. During the reaction process, H3NTA is degraded into IDA2- ligand. Structural analysis reveals that 1 is mononuclear and crystallizes in the monoclinic space group C2/c. Within the [Fe(IDA)2]- unit, Fe3+ shows six-coordinate distorted octahedral geometry. The [Fe(IDA)2]- units are connected by strong N1-H1···O4 hydrogen bonds to form anionic 2D supramolecular layers which are further connected by weak C-H···O hydrogen bonds to form a 3D metal-organic supramolecular host (MOSH) structure having 1D supramolecular channels along the crystallographic c-axis. DMA cations are present within the supramolecular channels through N2-H2···O2 hydrogen bonding interactions. Hirshfeld surface analysis and corresponding 2D fingerprint plots indicate that O···H interactions are the major supramolecular interactions present between MOSH and guest DMA cation. DFT calculations reveal that the HOMO and LUMO of the [Fe(IDA)2]- unit are composed of mixed metal-ligand orbitals. Both the absorption and emission spectra of the complex were studied in aqueous phase and the result was correlated with the TDDFT study. [ABSTRACT FROM AUTHOR]

Literature on the use of four chelating agents namely: ethylenediaminetetraacetic acid, nitrilotriacetic acid, diglycolic acid and iminodiacetic acid for the chromatographic separation of micro and macro amounts of rare earth elements was critically reviewed and supplemented with some new unpublished data from our Laboratory. Advantages and disadvantages of ion exchange chromatography both in cation and anion mode as well as ion interaction chromatography techniques, which were used for rare earth elements separation, are discussed. The usefulness of some of the chromatographic systems for micro–macro separations was discussed and demonstrated. The importance of resilience of the separation method to column overloading in some analytical and larger scale separations was emphasized. The methods described in this article might suit well for recovering of individual lanthanides and yttrium from e-waste and other industrial wastes which were fast accumulating in recent years. [ABSTRACT FROM AUTHOR]

It has proved that the photo-Fenton system modified by polycarboxylic acid is effective against the degradation of organic pollutants. Still, its effect and impact on actual water bodies are not clear. Therefore, this study mainly discussed the effect of actual water elements on the degradation of 2,4-Dichlorophenol in photo-Fenton system modified by Nitrilotriacetic acid (NTA) and its mechanism in pure water. The specific research contents were: the effect of initial concentration of 2,4-Dichlorophenol on its degradation efficiency; the effect of organic matters on the degradation of 2,4-Dichlorophenol; the effect of cations and anions; the effect of different actual water bodies. And the main results were as follows: In the effect of initial concentration, when the concentration of 2,4-Dichlorophenol was 20 mg·L−1, the degradation efficiency was the best (reached 100%). But, with the increase of initial concentration, the degradation efficiency of the system became worse and worse; the coexistence of the same kind of organic compounds can inhibit each other's degradation, and the degradation rate of pollutants in the mixed system was slower than that in the single system; the addition of anions and cations inhibited the degradation of 2,4-Dichlorophenol, and the degradation efficiency varied with the concentration of ions, in which the effect of anions was more complex; the degradation efficiency of 2,4-Dichlorophenol in three kinds of actual water bodies was lower than in deionized water, especially in PPMW. However, the degradation rates of DSTP and NLW were the fastest in the first 20 min. [ABSTRACT FROM AUTHOR]

Lead (Pb) soil contamination is widespread and poses a threat to human health. Even chronic exposure to low levels of Pb contaminated soils is potentially harmful to organisms. Remediation of Pb-contaminated soil can be accomplished through phytoextraction, a technique that uses plants and associated soil microorganisms. The North American native switchgrass (Panicum virgatum L.), a second-generation bioenergy crop was used in this study due to its ability to produce high biomass and grow on marginal lands. In this study the effects of exogenous foliar application of the plant growth regulators diethyl aminoethyl hexanoate (DA-6) and salicylic acid (SA) were examined separately but in conjunction with the soil-fungicide propiconazole and soil chelate nitrilotriacetic acid (NTA) in order to optimize phytoextraction of Pb. Plants were grown under controlled conditions using highly Pb-contaminated (5802.5 mg kg−1) soil derived from a superfund site. Foliar application of the plant growth regulator DA-6 resulted in significantly higher Pb concentrations in the foliage of plants compared to Control plants. The DA-6 did, however, not improve plants dry mass (DM). Foliar application of salicylic acid resulted in significantly greater DM of the foliage compared to Control plants. The DM of plants treated with foliar application of salicylic acid was 46% higher than those of Control plants. Foliar application of salicylic acid did not improve significantly Pb concentration of foliage compared to Control plants. The findings reported in this study will potentially improve phytoextraction by switchgrass grown in Pb contaminated soils. [ABSTRACT FROM AUTHOR]

Extraction of hazardous compounds by plants (phytoextraction) is considered a green technology for the remediation of soils and water bodies. Phytoextraction of mercury is very challenging due to the specific chemical/biochemical properties of this element and its low plant uptake. In this review, mechanisms and processes of enhancing phytoextraction of mercury are summarized. Plants that look promising for induced phytoextraction of mercury are described. Additives of various types that may significantly increase the efficiency of mercury phytoextraction are critically evaluated. Thiosulfates and other sulfur-containing compounds, aminopolycarboxylic acids, low-molecular-weight organic acids and enzymes are considered in detail. The important role of selective chemical inductors, primarily thiosulfates, is demonstrated. It is shown that synthetic aminopolycarboxylic acids have the potential for increasing bioavailability of mercury in soils and its translocation to above-ground organs of plants-phytoextractors. Non-chemical methods of inducing mercury phytoextraction are also addressed. Abbreviations: APCA: aminopolycarboxylic acid, BAF: bioaccumulation factor, BDL: below detection limit Cys: cysteine, DTPA: diethylenetriaminepentaacetic acid, DW: dry weight, EDDHA: ethylenediamine-N,N′-bis(2-hydroxyphenylacetic) acid, HEDTA: hydroxyethylethylenediaminetriacetic acid, IPEN: International Pollutants Elimination Network (), LMWOA: low-molecular-weight organic acid, MPC: below maximum permission concentration, ND: not detectable, NTA: nitrilotriacetic acid, PGPR: plant growth-promoting rhizobacteria, TF: translocation factor [ABSTRACT FROM AUTHOR]

In the modern era, copper toxicity has become progressively more common due to widespread applications of copper in metallurgy, plumbing, transportation, and electrical wiring industries which demands the development of economic methods for removal of copper(II) ions from various industrial/domestic effluents before their disposal. In this study, nitrilotriacetic acid-modified Dendrocalamus strictus charcoal powder (NTA-MDCP) was prepared and applied as an adsorbent for the removal of copper(II) ions from aqueous solutions. Batch mode adsorption experiments were performed to achieve the optimum adsorption parameters such as pH = 6, contact time = 2 h, adsorbent dose = 2 g/L. The adsorption data were analyzed using Langmuir, Freundlich, and Temkin isotherm models. Maximum adsorption capacity of NTA-MDCP for copper(II) ions from Langmuir isotherms was found to be 142.86 mg/g which may be attributed to affinity of NTA present on the surface of adsorbent toward 1:1 and 2:1 complex formation with copper (II) ions in solution. Thermodynamic studies of adsorption of copper (II) ions indicated the spontaneous and endothermic nature of adsorption process which was confirmed by negative ΔG (= −15.309 to −23.995 kJ/mol) and positive ΔH (= +3.719 to +63.119 kJ/mol) values, respectively, while kinetic study revealed that the adsorption process followed pseudo-second order. Before and after adsorption, surface characteristics of NTA-MDCP were examined using scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), Brunauer-Emmett-Teller (BET), carbon, hydrogen, nitrogen, and sulfur (CHNS) and X-ray diffraction (XRD) and the results obtained confirmed the accumulation of copper(II) ions on the surface of adsorbent. Regeneration of adsorbent was successfully carried out by the desorption process using calcium chloride solution (CaCl2: 5g/L). The present study revealed that NTA-MDCP could serve as a good adsorbent for the removal of copper(II) ions from aqueous solution certainly due to the chelating capacity of NTA. [ABSTRACT FROM AUTHOR]

Plant growth regulators(PGR)-assisted phytoremediation is a technique which could improve the efficiency of heavy metal accumulation in hyperaccumulator plants. The aim of this study was to explore the effects of PGR combination with nitrilotriacetic acid (NTA) on Cd extraction and distribution in Cd hyperaccumulator. To achieve this objective, a pot experiment was carried out to investigate the effects of the diethyl aminoethyl hexanoate (DA-6) and 24-epibrassinolide (24-EBL) and/or NTA on Cd phytoextraction, subcellular distribution and chemical forms in Amaranthus hybridus L. Results showed that NTA significantly decreased plant biomass production, but increased shoot and root Cd concentrations. Foliar spray containing DA-6 and 24-EBL alone increased both plant biomass and shoot and root Cd concentrations, the most pronounced effects observed were with 1 μM of DA-6. The combination of DA-6 and NTA inhibited toxicity and synergistically affected Cd uptake/accumulation. The addition of NTA alone enhanced Cd levels in soluble and cellular organelle fractions, whilst DA-6 and 24-EBL counteracted the toxic effects of Cd by promoting Cd retention in the cell walls, with 1 μM of DA-6 being the most effective dose. The NTA promoted metal mobility in shoots, resulting in increased Cd toxicity and stunted plant growth. In contrast, DA-6 and 24-EBL significantly reduced Cd mobility in plants. These results demonstrate that DA-6/24-EBL with NTA overcomes the detrimental effects of NTA on plant growth. Of the concentration ranges assessed, NTA + 1 μM DA-6 was optimal for the improving the remediation efficiency in A. hybridus. [ABSTRACT FROM AUTHOR]

Methane is a greenhouse gas, mainly generated from paddy fields and lakes by methanogens using hydrogen and acetic acid as substrates. In anaerobic environments with adequate Fe3+, iron-reducing microorganisms utilize these substrates, thus suppressing methane generation. We promoted Fe2+ oxidation to Fe3+ by physically stirring paddy soil and using a chelating agent (nitrilotriacetic acid; NTA) to evaluate the feasibility of the suppression of methane generation using Fe3+-reducing bacteria. Under anaerobic conditions, Fe3+ reduction to Fe2+ began immediately in the slurry made by adding water into air-dried paddy soil. Methane generation began on the 6th day when most Fe3+ was reduced. Under anaerobic conditions for 10 days followed by aerobic conditions, Fe2+ oxidation hardly progressed under static conditions. On stirring the slurry, Fe2+ oxidation progressed over 12 h (67% Fe2+ oxidized to Fe3+). When NTA was added under anaerobic conditions followed by stirring under aerobic conditions, Fe2+ oxidation was promoted further. The idea of physical stirring of paddy soil in the actual environment was derived from the effects of paddy soil stirring by ducks in interrelated rice–duck farming. In such farming, paddy soil contains more Fe3+ in its surface water compared with normal farming, resulting in suppressed methane generation. [ABSTRACT FROM AUTHOR]

At present, the remediation for organic pollutants and heavy metals co-contaminated soils is a challenge which needs to be broken through. In this study, alkyl polyglucoside (APG), citric acid (CA), and nitrilotriacetic acid (NTA) were chosen to enhance the phytoremediation of pyrene and Pb co-contaminated soils by perennial ryegrass. Through the comparison of the results with different applications, it could be found that the application of NTA was beneficial to the growth of perennial ryegrass, the underground and aboveground biomass were increased by 172.9-236.1% and 61.9-142.8%, respectively, meanwhile, photosynthetic activity of perennial ryegrass was affected positively. More importantly, the combined application of APG and NTA maximally promoted the accumulation and translocation of Pb (BF/TF, 0.44/0.61) and dissipation of pyrene (71.6%). These results indicated that the combined application of APG and NTA could be promising for future practical application of phytoremediation. However, the optimal dosage ratio of APG and NTA for phytoremediation needs to be further researched. [ABSTRACT FROM AUTHOR]

The mutual effects ofAcidiphilium cryptum, nine ligands and dissolved iron on jarosite dissolution were studied in a 23full factorial experiment. Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA) and oxalic acid were able to dissolve jarosite chemically, but bacterial action enhanced this dissolution; from 88 ± 1, 46 ± 0 and 36 ± 0 µmol/L d to 129 ± 3, 177 ± 5 and 106 ± 14 µmol/L d, respectively. Oxalate and NTA exhibited a synergistic effect with dissolved iron and bacteria that may be explained by a model in which iron complexes behave as redox mediators in the microbial respiration in which jarosite, a solid substrate, serves as terminal electron acceptor. [ABSTRACT FROM PUBLISHER]

At elevated temperatures, the corrosion of carbon steel and Type 304 stainless steel is high in media containing polycarboxylic acids such as nitrilotriacetic acid, which is a reagent used for the decontamination of nuclear reactor coolant systems. Hence, three commercial corrosion inhibitors (Philmplus 5K655, Prosel PC-2116, and Ferroquest LP7203) were evaluated for high-temperature applications. Preliminary screening of the inhibitors was done by electrochemical techniques, namely, polarization and impedance spectroscopy. Philmplus showed maximum corrosion inhibition efficiency and hence was used for high-temperature investigations. A concentration of 500 mg/L was found to be optimum. The high-temperature dissolution of corrosion product oxides such as magnetite and nickel ferrite that are relevant to nuclear reactors was also carried out in the presence of Philmplus. During the decontamination process, which involves the dissolution of corrosion product oxides, it is desirable to use an inhibitor that will alleviate the corrosion of the underlying base metal without compromising on the dissolution of the oxides present over it. Investigations were also carried out to evaluate hydrazine as a corrosion inhibitor for high-temperature applications; the results obtained were comparable to those of Philmplus. [ABSTRACT FROM AUTHOR]

Analogues of iminodiacetic acid (H2IDA) and nitrilotriacetic acid (H3NTA) bearing two (hydroxomethyl)methylphosphinate or (2-carboxyethyl)methylphosphinate groups were synthesized. Their acid-base and coordination properties with divalent metal ions (Cu2+, Ni2+and Zn2+) were studied by potentiometry. The compounds exhibit very low basicity of the amino groups (pKa= 6.2–7.6) due to presence of two electron-withdrawing methylphosphinate groups and, consequently, a low stability of the complexes. In the case of IDA-analogues, the low complex stability results in precipitation of metal hydroxides in neutral region. As expected, NTA-analogues form more stable complexes and, thus, they were also studied in the alkaline region. Presence of additional carboxylate in the 2-carboxyethylphosphinic acid groups results in the formation of dinuclear complexes. Solid-state structures of two compounds were determined by X-ray diffraction analysis. The compounds are protonated on the nitrogen atom and the structures are stabilized by rich hydrogen bond network. [ABSTRACT FROM PUBLISHER]

The preparation and application of biosensors for the determination of amyloid-beta16–23′peptide are described. The redox active nitrilotriacetic acidsingle-copper(II)-histidine6-receptor for advanced glycation end products V domain and redox active nitrilotriacetic aciddouble-Cu(II)-histidine6-receptor for advanced glycation end products V domain complexes were employed as an analytically active layer of biosensors. The preparation procedure consists of three steps: creation of a mixed layer composed ofN-acetylocysteamine and thiol derivatives of nitrilotriacetic acid, complexation of Cu(II) on theN-acetylocysteamine-nitrilotriacetic acid layer, and immobilization of histidine-tagged V domains, natural or mutant on the surface of a gold electrode modified with aN-acetylocysteamine-nitrilotriacetic acid layer. The biosensors were used for the study of the interactions between the histidine-tagged V domains of receptor for advanced glycation end products and amyloid-beta16–23′peptide. Each step was controlled by cyclic voltammetry, Osteryoung square-wave voltammetry, and atomic force microscopy. Comparisons of the electrochemical parameters of biosensors, incorporating single as well as double nitrilotriacetic acid molecules, were investigated. Both types of biosensors were used for determination of amyloid-beta16–23′peptide, and the mechanism of electroanalytical signals generation is reported. [ABSTRACT FROM PUBLISHER]

Cucumber mosaic virus (CMV), causing mosaic disease in banana cultivars, is the most widespread virus after Banana bunchy top virus. The entire coat protein (CP) gene of CMV was amplified by polymerase chain reaction (PCR) and engineered to be expressed in bacterial expression vector pQE30, under the control of isopropyl-thio-β-d galactopyranoside (IPTG)-inducible T7lac promoter. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) revealed expressed CP as ∼25 kDa protein. Expression conditions for maximum recovery of soluble recombinant protein were standardised. The recombinant CP (r-CP) fused with His-tag was purified from Escherichia coli using nickel-nitrilotriacetic acid (Ni-NTA) resin and used as an antigen for the production of polyclonal antisera. This antiserum was used to develop enzyme-linked immunosorbent assay (ELISA) and immunocapture reverse transcription-polymerase chain reaction (IC-RT-PCR) based assay for the detection of CMV isolates. The antiserum had a titre of 1:8000 when tested with r-CP. The reaction of polyclonal antisera was much better than that of commercial antibody. On comparing IC-RT-PCR with direct antigen coating-enzyme-linked immunosorbent assay (DAC-ELISA) using polyclonal antisera, IC-RT-PCR was found to be more sensitive, hence can be used to detect the presence of virus in tissue culture based banana plant as well as in various host plants. [ABSTRACT FROM AUTHOR]

The therapeutic efficacy of anticancer drugs like doxorubicin can be significantly increased by their incorporation into liposomes, but an ability to actively target the drug-containing liposomes to tumors could well provide an even greater curative effect. In this work, a commercial preparation of doxorubicin-loaded liposomes (Caelyx) was modified by incorporation of the metal chelator lipid 3(nitrilotriacetic acid)-ditetradecylamine (NTA3-DTDA) to enable engraftment of histidine-tagged targeting molecules. Our results show that when engrafted with p15-RGR, a His-tagged peptide containing a sequence purported to bind platelet-derived growth factor receptor ββ (PDGFRββ), NTA3-DTDA-containing Caelyx (3NTA-Caelyx) can be targeted to NIH-3T3 cells in vitro, leading to increased cytotoxicity compared with non-targeted 3NTA-Caelyx. PDGFRββ is known to be expressed on pericytes in the tumor vasculature; however, when radiolabeled p15-RGR liposomes were administered to mice bearing subcutaneous B16-F1 tumors, minimal accumulation into tumors was observed. In contrast, an alternative targeting peptide, p46-RGD, was found to actively direct liposomes to tumors (4.7 %ID/g). Importantly, when injected into tumor-bearing mice, p46-RGD-engrafted 3NTA-Caelyx significantly decreased the tumor growth rate compared with controls. These results indicate that the incorporation of NTA3-DTDA into liposomal drugs could represent a simple modification to the drug to allow engraftment of targeting molecules and to increase its efficacy. [ABSTRACT FROM AUTHOR]

A comparison of the electrochemical behavior of Ce(IV) and its complexes of ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminedisuccinic acid (EDDS), and nitrilotriacetic acid (NTA) using cyclic voltammetry (CV) and rotating disc electrode (RDE) on Pt-electrode were carried out. All complexes had an anodic cathodic ratio greater than 1. The Ce(IV)-DTPA had the best properties: highest peak potential, better reversibility, and higher peak current. Potential usage of the Ce(IV)-DTPA in redox flow batteries (RFB) was confirmed by the electrochemical impedance spectroscopy results: lowest electrolyte and charge transfer resistance. The performance evaluation of RFB employing Ce(IV) and Ce(IV) complexes of DTPA and EDTA with constant current charge/discharge analysis proved that CE(IV)-DTPA complex has a potential as an anode in RFB. A maximum potential of 1 V and a minimum voltage of 2 V were achieved. Highest energy, voltage, and coulombic efficiencies of 85%, 93%, and 92% were obtained, respectively. [ABSTRACT FROM AUTHOR]

The development of methods for the off-on switching of immobilization or presentation of cell-adhesive peptides and proteins during cell culture is important because such surfaces are useful for the analysis of the dynamic processes of cell adhesion and migration. This paper describes a chemically functionalized gold substrate that captures a genetically tagged extracellular matrix protein in response to light. The substrate was composed of mixed self-assembled monolayers (SAMs) of three disulfide compounds containing (i) a photocleavable poly(ethylene glycol) (PEG), (ii) nitrilotriacetic acid (NTA) and (iii) hepta(ethylene glycol) (EG7). Although the NTA group has an intrinsic high affinity for oligohistidine tag (His-tag) sequences in its Ni2+-ion complex, the interaction was suppressed by the steric hindrance of coexisting PEG on the substrate surface. Upon photoirradiation of the substrate to release the PEG chain from the surface, this interaction became possible and hence the protein was captured at the irradiated regions, while keeping the non-specific adsorption of non-His-tagged proteins blocked by the EG7 underbrush. In this way, we selectively immobilized a His-tagged fibronectin fragment (FNIII7-10) to the irradiated regions. In contrast, when bovine serum albumin—a major serum protein—was added as a non-His-tagged protein, the surface did not permit its capture, with or without irradiation. In agreement with these results, cells were selectively attached to the irradiated patterns only when a His-tagged FNIII7-10 was added to the medium. These results indicate that the present method is useful for studying the cellular behavior on the specific extracellular matrix protein in cell-culturing environments. [ABSTRACT FROM AUTHOR]

Ion chromatographic separation of rare earth elements (REE) was studied using isocratic elution from Dionex Ion Pac CS3 + CG3 column with sulfonic acid functional groups and buffered solutions of tartaric (HTart), citric (HCit) and nitrilotriacetic (NTA) acids, respectively, at temperatures 25-70°C. Apparent atomic numbers (App.At.No.) of Y and Sc with respect to lanthanide series were established and found to vary widely both with the ion exchange system and with temperature. A novel method for the separation of Dy-Y-Tb triad was proposed using 68 m mol L-1 HCit, pH = 3.18 at T = 60°C and its capability to be used for analytical determinations was demonstrated. The significance of contribution of longitudinal diffusion in the stationary phase to total zone spreading in the systems studied was emphasized. [ABSTRACT FROM AUTHOR]

Two lead coordination compounds [Pb2(nta)]NO3 (1) and [Pb(oda)] (2) have been synthesized by slow evaporation or hydrothermal conditions using nitrilotriacetic acid (nta) and 2,2'-oxydiacetic acid (oda) as ligands, respectively. Their structures were determined by single-crystal X-ray diffraction and further characterized by X-ray powder diffraction, infrared absorption spectrum, and thermogravimetric analysis. Compound 1 is a 2-D honeycomb-like layer structure with (6,3) topology. When the bonding limit of Pb-O extends from 2.76 to 2.90 Å, potential weak Pb-O bonds can be found in 1, and the 2-D layer structure can be further linked to generate a 3-D 4-connected supramolecular sra net with the (42.63.8) Schlafli symbol. Compound 2 contains a 1-D infinite Pb-O chain which is connected through µ3-, µ4-, and µ5-coordination modes of oda to form a new 3-D structure. [ABSTRACT FROM AUTHOR]

Kinetics of the oxidation of [CoII(nta)(bz)(H2O)2]2- (nta = nitrilotriacetate and bz = benzoate) by periodate in acetate medium have been investigated spectrophotometrically at 580 nm under pseudo first order condition by taking large excess of [image omitted] over the 15.0-35.0°C range at pH = 4.99 and I = 0.50 M. The kinetics in acetate medium obeyed the rate law: [image omitted] Also, the oxidation of [CoII(nta)(bz)(H2O)2]2- by periodate in the presence of Mn(II) as a catalyst was carried out. The rate of reaction increases as the concentration of Mn(II) increases. Initial cobalt(III) products were formed and slowly converted to final products, fitting an inner-sphere mechanism. The enthalpy and entropy of activation were measured using the transition state theory equation. [ABSTRACT FROM AUTHOR]

Complexes of vanadium(IV) with aminopolycarboxylic acids, nitrilotriacetic (NTA), nitrilodiaceticpropionic (NDAP), nitrilodipropionicacetic (NDPA), and nitrilotripropionic (NTP) acids were studied by electromotrice force measurements [emf(H)] in 3.0 M KCl ionic medium at 25°C. Data analysis using the least-squares program LETAGROP, according to the general reaction p H+ + q VO2+ + r C3- ⇆ Hp(VO)qCrp+2q-3r, indicates that the following complexes are formed (H3C ligands): NTA ([VOC]- and [OHVOC]2-); NDAP ([VOC]- and [OHVOC]2-); NDPA ([VOC]- and [OHVOC]2-); and NTP ([H2VOC]+, HVOC, [VOC]-, and [OHVOC]2-). The following order of coordination capacity NTA > NDAP > NDPA > NTP is suggested, based on values of stability constants and is attributed to the increase in propionic groups in the sequence. The study confirms that five-membered ring chelates are the most stable for VIV, like CuII, NiII, lanthanides, and other heavier elements. [ABSTRACT FROM AUTHOR]

In an attempt to obtain ternary copper(II) [Cu(II)] complexes where bis(2-pyridyl) ketone (bpk) could induce the fac-O2 + N(apical) conformation in the HL2- form of two different nitrilotriacetates (HNTA2- and HDNTA2-), we obtained [Cu(bpmd)2][Cu(HNTA)2] · 2H2O (1) and [Cu(bpmd)2](H2DNTA)2 · 4H2O (2) where bpmd is di(2-pyridyl)methanediol. On this basis, the salt [Cu(bpmd)2][Cu(IDA)2] · 6H2O (3) [iminodiacetate (IDA) ligand] was also obtained. The crystallographic studies of these compounds revealed that the common cation of these salts results from aquation of bpk in the aqueous media. The aquation of bpk is unexpectedly fast in the case of 1 because crystals appeared on the same day of the synthesis. [ABSTRACT FROM AUTHOR]

Using nta (H3nta = nitrilotriacetic acid) as a bridging ligand, a new dinuclear copper(II) complex [Cu2(μ-nta)(phen)3](ClO4)· 2H2O (1) (phen = 1, 10-phenanthroline) has been synthesized and its structure and magnetic properties have been studied. In compound 1, two Cu(II) atoms take different coordination environments. One is pentacoordinated with a square pyramidal geometry; another is six-coordinated with a octahedral geometry. The temperature-dependent magnetic susceptibility measurements indicate the existence of a strong antiferromagnetic coupling between Cu(II) ions. [ABSTRACT FROM AUTHOR]

Efficient synthesis of dioxopiperazines-diketopiperzines (DKPs)- and amide from nitrilotriacetic acid (NTA) using microwave irradiation and classical heating were described. All compounds were characterized using 1H NMR, 13C NMR and elemental analysis. Antimicrobial effects of these compounds are also investigated. All tested compounds showed moderate antimicrobial activity. [ABSTRACT FROM AUTHOR]

Greenhouse experiments were conducted to study the effects of chelating agents on the growth and metal accumulation of Chinese brake fern (Pteris vittata L.), vetiver (Vetiveria zizanioides L.), and rostrate sesbania (Sesbania rostrata L.) in soil contaminated with arsenic (As), Cu, Pb, and Zn. Among the five chelating agents used [ethylenediaminetriacetic acid (EDTA), hydroxyethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), oxalic acid (OA), and phytic acid (PA)], OA was the best to mobilize As, EDTA to mobilize Cu and Pb, and HEDTA to mobilize Zn from soil, respectively. The biomass of vetiver was the highest, followed by rostrate sesbania. All chelating agents inhibited the growth of Chinese brake fern and rostrate sesbania, but HEDTA significantly increased the aboveground biomass of vetiver. Dry weights of both Chinese brake fern and rostrate sesbania decreased with increasing EDTA concentrations amended in the soil, especially in treatments with high EDTA concentrations. EDTA and HEDTA enhanced Cu, Zn, and Pb, but lowered As accumulation in all three plant species, except for As in vetiver, while OA significantly enhanced As accumulation in the aboveground part of vetiver. Concentrations of Cu, Zn, and Pb in the aboveground parts of plants increased significantly with the increase of EDTA concentrations and treatment time. In addition to As, Chinese brake fern also accumulated the highest Cu, Pb, and Zn in its aboveground parts among the three plant species grown in metal-contaminated soil with EDTA/HEDTA treatments. This species, therefore, can be used to simultaneously clean up As, Cu, Pb, and Zn from contaminated soils with the aid of EDTA or HEDTA. [ABSTRACT FROM AUTHOR]

Photocatalytic reduction (PCR) of Cr(VI) in a TiO2 suspension was studied at pH 4 in the presence of organic compounds containing different numbers of carboxyl groups. The compounds studied were glycine (Gly), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA). In all the cases, near complete Cr(VI) removal was observed after 60 minutes. During PCR process, the aqueous Cr(VI) concentration measured with both Ion Chromatography and Atomic Absorption Spectrophotometery was different in the presence of IDA and EDTA as reaction proceeded while little difference was observed in a control test. This result suggests that a greater portion of reduced Cr(III) species was possibly dissolved through complex formation with IDA (Cr(III)-IDA) and EDTA (Cr(III)-EDTA) or with reaction intermediates (Cr(III)-organic complexes) during PCR compared to the control test. As the number of carboxyl group increased Cr(VI) reduction increased and showed a good linear relationship between initial rates of Cr(VI) reduction and adsorption density of carboxyl group of the surface of TiO2. The initial rate of Cr(VI) reduction in the presence of EDTA was 5 times greater than that in control. When the PCR process was applied in the treatment of real wastewater, an effective Cr(VI) reduction was observed with addition of EDTA. [ABSTRACT FROM AUTHOR]

New biocatalysts were developed using organophosphorus hydrolase (OPH, EC 3.1.8.1) with a polyhistidine tag at the N-terminus of the protein (His6-OPH). The use of His6-OPH together with previously developed approaches for the entrapment of cells into poly(vinyl alcohol) cryogels and covalent immobilization of enzymes into porous fabric materials, impregnated with chemically cross-linked chitosan sulphate gel, enabled dramatic improvement of catalytic characteristics against various organophosphorous compounds (OPCs; Paraoxon, Coumaphos, Methyl parathion, etc.). The polyhistidine tag of OPH was used to create a new immobilized biocatalyst using metal-chelating carriers, such as Ni2+-nitrilotriacetic acid-agarose and Co2+-iminodiacetic acid-polyacrylamide cryogel. The latter biocatalyst had high activity and stability for the continuous hydrolysis of OPCs. [ABSTRACT FROM AUTHOR]

The degradation of Nitrilotriacetic Acid (NTA), which results from the oxidation of hydroxyl radicals formed in the process, is a major deficiency in the present Fe-NTA system for the oxidation of hydrogen sulfide to sulfur by air. The degradation of NTA can be slowed down considerably by the addition of a hydroxyl radical scavenger. In this study, a series of inorganic and organic materials was tested as scavengers/inhibitors of hydroxyl radicals in attempts to improve the Fe-NTA system. The results showed that N-methylpyrrolidinone and ethylene glycol could be used as potentially powerful scavengers of hydroxyl radicals to improve the Fe-NTA system. [ABSTRACT FROM AUTHOR]

An automated sequential‐injection online preconcentration system was developed for the determination of lead by inductively coupled plasma–atomic emission spectrometry (ICP‐AES). The preconcentration of lead was performed with a minicolumn containing a lead‐selective resin, Analig Pb‐01, which was installed between a selection and a switching valve. In an acidic condition (pH 1), lead could be adsorbed on the resin. The concentrated lead was afterward eluted with 25 µL of 0.06 M nitrilotriacetic acid (NTA) solution (pH 9) and was subsequently transported into the nebulizer of ICP‐AES for quantification. The selectivity of the resin toward lead was examined using a solution containing a mixture of 61 elements. When a sample volume of 5 mL was used, the quantitative collection of lead (≥⃒97%) was achieved, along with an enrichment factor of 19, a sampling frequency of 12 samples hr-1, a detection limit of 70 pg mL-1, and a lowest quantification limit of 100 pg mL-1. The linear dynamic range was 0.1 to 5 ng mL-1, and the relative standard deviation (n=9) was 0.5% at a 5 ng mL-1 Pb level. The detection limit of 30 pg mL-1 and lowest quantification limit of 50 pg mL-1 could be achieved when 10 mL of sample volume was used. The accuracy of the proposed method was validated by determining lead in the standard reference material of river water (SLRS‐4), and its applicability to the determination of lead in environmental river water samples was demonstrated.The authors were invited to contribute this paper to a special issue of the journal entitled “Spectroscopy and Automation”. This special issue was organized by Miguel de la Guardia, Professor of Analytical Chemistry at Valencia University, Spain. [ABSTRACT FROM AUTHOR]

Hydrothermal reactions of Nd(ClO 4 ) 3 ·6H 2 O, Gd(ClO 4 ) 3 ·6H 2 O and Er 2 O 3 with H 3 NTA (nitrilotriacetic acid) afford three new lanthanide coordination polymers, {[Nd(NTA)(H 2 O)]· 2H 2 O} n (1), {[Gd(NTA)(H 2 O)]·2H 2 O} n (2) and {[Er(NTA)(H 2 O)]·H 2 O} n (3), characterized by elemental analysis and IR spectroscopy. X-ray single crystal structural analyses showed that 1 and 2 are an isomorphous 2D-layered framework containing the nine-coordinated Nd(III) (or Gd(III)), and woven into a 3D suprastructure by interlayer hydrogen bonding while 3 is a 3D structure with eight-coordinate Er(III). [ABSTRACT FROM AUTHOR]

The formation constants of species formed in the systems H +   +  W(VI)  +  nitrilotriacetic acid (NTA) and H +   +  NTA have been determined in aqueous solution for pH  =  4–9 at 25°C and different ionic strengths ranging from 0.1 to 1.0  mol  dm -3 NaClO 4 , using potentiometric and spectrophotometric techniques. It was shown that tungsten(VI) forms a mononuclear 1  :  1 complex with NTA of the type WO 3 L 3- at pH  =  7.5. The composition of the complex was determined by the continuous variations method. The complexation of molybdenum(VI) with glutamic acid was investigated in aqueous solution ranging in pH from 4 to 9, using polarimetric, potentiometric and spectrophotometric techniques. The composition of the complex was determined by the continuous variations method. It was shown that molybdenum(VI) forms a mononuclear 1  :  1 complex with glutamic acid of the type MoO 3 L 2- at pH  =  6.0. The dissociation constants of glutamic acid and the stability constants of the complex were determined at 25°C and at ionic strengths ranging from 0.1 to 1.0  mol  dm -3 sodium perchlorate. In both complex formation reactions the dependence of the dissociation and stability constants on ionic strength is described by a Debye-Huckel type equation. Finally, a comparison has been made between the patterns of ionic strength dependence for the two complexes and the results have been compared with data previously reported. [ABSTRACT FROM AUTHOR]

Two cobalt complexes [NaCo II (nta)(H 2 O)] n (H 3 nta  =  nitrilotriacetic acid) (1) and NH 4 [Co III (ida) 2 ]  ·  2H 2 O (H 2 ida  =  iminodiacetic acid) (2) have been synthesized and characterized by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the orthorhombic system, space group P 2 1 2 1 2 1 with a   =  7.9770(12)  Å, b   =  9.7613(15)  Å, c   =  12.1945(18)  Å, V   =  949.5(2)  Å 3 , Z   =  4, and R 1   =  0.0705 for 1597 observed reflections. Compound 2 crystallizes in the monoclinic system, space group P 2(1)/ c with a   =  5.1801(3)  Å, b   =  11.2073(6)  Å, c   =  12.2891(7)  Å, V   =  707.09(7)  Å 3 , Z   =  2, and R 1   =  0.0349 for 1143 observed reflections. In compound 1, the Co is coordinated by a nitrogen and five oxygen atoms in a distorted octahedral geometry {CoNO 5 }, and the Na is coordinated by one water molecule and four carboxyl oxygen atoms in slightly distorted square pyramidal geometry. The entire structure shows a three-dimensional network. In compound 2, Co atom is equatorially coordinated by two ida ligands in a distorted octahedral geometry {CoN 2 O 4 }. The discrete [Co(ida) 2 ] 2- anions are linked by hydrogen bonding to a three-dimensional supramolecular network. [ABSTRACT FROM AUTHOR]

Four new complexes [UO2(HNTA)(H2O)]·3H2O, Na[UO2(NTA)]·(H2O), [ZrO(HNTA) (H2O)]·3H2O and Na[ZrO(NTA)]·H2O were obtained by the reactions of and ZrO 2+ salts with nitrilotriacetic acid (NTA) dissolved in water and NaOH aqueous solution. Infrared spectra of the solid complexes have been obtained and assigned on the basis of C s symmetry. Octahedral and polymeric chain structures are adopted for the uranyl and zirconyl NTA complexes, respectively. Thermogravimetric (TG) and differential thermal analysis (DTA) data are in accordance with the proposed structures and show that the complexes decompose to metal oxides. [ABSTRACT FROM AUTHOR]

Dehydration of serine derivatives into didehydroamino acids and subsequent conjugate addition of nitromethane led to novel nitro derivatives of nitrilotriacetic acid and ethylenediaminetetraacetic acid. Straightforward transformations of these compounds allowed the synthesis of bifunctional and trifunctional metal‐chelating agents via an Henry reaction. [ABSTRACT FROM AUTHOR]

Three different β-cyclodextrins, peracylated on the primary hydroxymethyl rim of the cyclodextrin (6-C n ) 7 β-CD, and nine different nitrilotriacetic acid-modified inclusion ligands (R-NTA) have been prepared and their self-assembly properties characterized. These modular amphiphiles have been developed to promote two-dimensional crystallization of proteins at the lipid-water interface. Pressure-area isotherm data suggest that the occupancy of the host sites within the (6-C n ) 7 β-CD monolayers vary as a function of the known host-guest binding constant for the unmodified β-CD host and R guest substituents. Negative-stain TEM experiments show that vesicles are formed upon mild sonication of (6-C 10 ) 7 β-CD and (6-C 16 ) 7 β-CD in 10 mM Tris, pH 7.4 buffer. These results indicate that (6-C n ) 7 β-CD forms stable lyotropic phases that may be useful for templating the interfacial crystallization of histidine-tagged proteins or other molecules capable of interacting with the R-NTA guest ligands. [ABSTRACT FROM AUTHOR]

n iron chelate, ferric nitrilotriacetate (Fe-NTA), induces acute proximal tubular necrosis as a consequence of lipid peroxidation and oxidative tissue damage, that eventually leads to high incidence of renal adenocarcinomas in rodents. This study was designed to investigate the effect of quercetin, a bioflavonoid with antioxidant potential, on Fe-NTA-induced nephrotoxicity in rats. One hour after a single intraperitoneal (i.p.) injection of Fe-NTA (8 mg iron/kg), a marked deterioration of renal architecture and renal function was observed. Fe-NTA induced a significant renal oxidative stress demonstrated by elevated thiobarbituric acid reacting substances (TBARS) and reduction in activities of renal catalase, superoxide dismutase and glutathione reductase. Pretreatment of animals with quercetin (2 mg/kg, i.p.) 30 minutes before Fe-NTA administration markedly attenuated renal dysfunction, morphological alterations, reduced elevated TBARS and restored the depleted renal antioxidant enzymes. These results clearly demonstrate the role of oxidative stress and its relation to renal dysfunction, and suggest a protective effect of quercetin on Fe-NTA-induced nephrotoxicity in rats. [ABSTRACT FROM AUTHOR]

In ligand-modified, colloid-enhanced ultrafiltration (LM-CEUF), a ligand that selectively complexes target ions (e.g., lead) also associates with a water-soluble colloid, such as a surfactant micelle or polyelectrolyte. The colloid, associated ligand, and target ion are then concentrated using ultrafiltration, producing a filtrate with a low concentration of the target ion. Dialysis, ultrafiltration, and potentiometric titration experiments have been used to investigate the effectiveness of four nitrilotriacetic acid (NTA) derivatives in the removal of lead from aqueous solution through LM-CEUF. The ligands are 2-phenyl nitrilotriacetic acid (PNTA), 2-[N, N-di-(carboxymethyl)]amino-octanoic acid (HNTA), 2-[N,N-di-(carboxymethyl)]amino-dodecanoic acid (DNTA), and 2-[N,N-di-(carboxymethyl)]amino-3-sulfopropionic acid (SNTA). The colloids used were the cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDADMAC) and the cationic surfactant cetylpyridinium nitrate (CPNO3). In equilibrium dialysis and ultrafiltration (UF) experiments, SNTA and PDADMAC systems provided effective lead removal. In semiequilibrium dialysis and UF experiments, DNTA and CPNO3 systems also provided effective lead removal. The effects of pH, ionic strength, competing ions, and colloid concentration were investigated for each ligand system. Ligand protonation constants and ligand–metal stability constants were obtained for SNTA in both water and solutions of PDADMAC and for DNTA in solutions of CPNO3. Ligand regeneration through pH adjustment and metal precipitation with various anions was also demonstrated. [ABSTRACT FROM AUTHOR]

The effect of NTA (nitrilotriacetic acid) and elemental sulfur (S), two soil amendments suggested for the enhancement of metal phytoavailability in phytoextraction, on heavy metal uptake by Nicotiana tabacum (tobacco) and Zea mays (maize) were studied and compared in two Zn-, Cu-, Cd-, and Pbcontaminated soils from northern Switzerland. Experiments were performed in the greenhouse with topsoil (0 to 20 cm) material from two locations, Dornach and Rafz. The Dornach soil was calcareous and had been contaminated by dust emissions from a nearby brass metal smelter. The Rafz soil, free of carbonates, had been pofiuted by former sewage sludge application. Soft amendments with S increased the solubility (NaNO[sub 3] extraction) of Zn and Cd about 10-fold in Dornach soft and up to 30fold in Rafz soft after 55 days. Zn and Cd removal by N. tabacum and Z. mays, however, increased only about 5.5- and 2.5fold in these treatments in Rafz soil, respectively, while in the Dornach soft only a slight increase for Cd was found. Repeated NTA application increased soluble Zn, Cu, and Cd about 100-, 20-, and 19-fold in the Dornach soft and 13-, 4-, and 2-fold in the Rafz soft shortly after application. Soluble Pb was increased by NTA up to 50-fold in Rafz soil. After 90 days soluble heavy metal concentrations were only slightly elevated in both soils. Again, however, Zn, Cd ,and Cu removal by N. tabacum and Z. mays increased only about 1.5- to 2.5-fold in the two soils, whereas Pb removal by N. tabacum increased about fivefold in the Rafz soft as a result of NTA application. [ABSTRACT FROM AUTHOR]

A new method, paper electrophoresis, involving the use of a ionophoretic technique is described for the study of equilibria in mixed-ligand systems in solution. The migration of a metal ion spot (M), under an electric field with complexants added in the background electrolyte at the fixed pH 8.5 is studied. For the study of ternary complexes, the concentration of the primary ligand, adenosine monophosphate (AMP), is kept constant while that of the secondary ligand, nitrilotriacetate (NTA), is varied. Plots of log [NTA] against mobility provided information about the mixed-ligand complex allowing calculation of the stability constants. As a prerequisite, the binary equilibria of M(II)-AMP and M(II)-NTA have also been studied. The overall stability constants (log K) of the M(II)-AMP-NTA complexes have been found to be 7.31 and 8.25 for the Mn(II) and Pb(II) complexes, respectively, at u = 0.1 and at 30 ± 0.1 °C [ABSTRACT FROM AUTHOR]