Combination Of Chelating Agents Research Articles

Effect of Low-Molecular-Weight Organic Acids on Migration Characteristics of Pb in Reclaimed Soil.

The effect of low-molecular-weight organic acids (citric acid and malic acid) on the migration characteristics of Pb in contaminated soils was explored in this study. Reclaimed soil was collected from the coal gangue hill area of the Panyi mine in Huainan City (China). The effect of citric acid and malic acid on the form of Pb present in the reclaimed soil was analyzed by spiking soil samples and simulating Pb-contaminated soil. The results indicate the following. 1) With increased concentration of exogenous Pb, the activity of Pb in the reclaimed soil was effectively improved. 2) The addition of citric acid and malic acid both resulted in an increased fraction of exchangeable Pb in the soil, which effectively promoted the active Pb fraction. As the concentrations of citric acid and malic acid increased, the active Pb fraction of the reclaimed soil increased accordingly. The Pb activation effect of citric acid was observed to be greater than that of malic acid. 3) With extended soil aging time, the activation effect of organic acids on Pb weakened, with the loosely bound Pb gradually transforming into strongly bound Pb. Chelating agents can activate heavy metals in soil, mainly through the combination of chelating agents and heavy metal ions in the soil solution to form soluble metal chelates, so as to increase the bioavailability of heavy metals in soil to plant roots. Therefore, adding citric acid can be considered as a strategy to enhance the efficiency of reclaimed soil remediation because of the ability of Pb activation.

Use of synergistic mixture of chelating agents for in situ LDH growth on the surface of PEO-treated AZ91

The principal possibility to grow layered double hydroxide (LDH) at ambient pressure on plasma electrolytic oxidation (PEO) treated magnesium alloy AZ91 in the presence of chelating agents is demonstrated for the first time. It avoids hydrothermal autoclave conditions, which strongly limit wide industrial application of such coating systems, and the presence of carbonate ions in the electrolyte, which lead to the formation of “passive” non-functionalizable LDH. A combination of chelating agents (sodium diethylenetriamine-pentaacetate (DTPA) and salicylate) were introduced to the treatment solution. The role of each additive and the influence of treatment bath composition on the LDH formation processes are discussed. A synergistic effect of DTPA and salicylate during LDH formation is discovered and its possible explanation is proposed.

Structural and optical properties of cadmium magnesium zinc oxide (CdMgZnO) nanoparticles synthesized by sol–gel method

Nanoparticles of CdxMg0.12−xZn0.88O(0≤x≤0.02) were synthesized by a simple sol gel route with the combination of chelating agents. Effect of cadmium on the phase, structural, morphological and optical properties of the synthesized nanoparticles has been studied and reported by using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR) and UV–Vis diffuse reflectance spectroscopy (UV–vis DRS). The crystal size, lattice parameters, unit cell volume, X-ray density, inter-planar distances and bond length were obtained and analyzed from the XRD data. The X-ray analysis reveals the formation of a single phase with a hexagonal wurtzite structure, where an increase of the cell volume was achieved as the Cd content was increased as well. Synthesized nanoparticle were nearly spherical at nano-size regime and are loosely agglomerated as observed from the SEM analysis. EDX spectra of the composition confirmed the appropriate stoichiometric ratio. A fundamental absorption peak centered at 375 nm was observed from the UV–visible absorption spectra which shifted towards a higher wavelength correlating the narrowing of the energy band gap due to increase in Cd content. The structural adjustment from the IR spectra confirmed the stretching vibration of Zn–O in the CdxMg0.12−xZn0.88O lattice with Cd content.

Effect of Some Bacteria and Iron Chelators on Potato Colonization by Arbuscular Mycorrhiza Fungi Inoculated by Rhizoctonia

Background/Objectives: Arbuscular mycorrhiza is a symbiosis between plants and glomeromycota fungi. This relationship gives several important benefits to the plants including increasement tolerance against abiotic and biotic stresses. Methods/Statistical Analysis: In this study, the effects of Plant Growth Promoting Rhizobacterium (PGPR) and chemical chelating factors (EDTA, EDDHA) in the presence of Rhizoctonia solani AG3 were studied on mycorrhizal colonization on potato. To investigate the mycorrhizal colonization percentage, root staining was performed. The existence of hyphae, vesicle and arbuscule estimate as Arbuscular mycorrhiza colonization. Findings: The results revealed that interaction of chelating factor of iron (EDTA and EDDHA) mycorrhizal colonization and bacterial strains had positive effects on root colonization and in consequence leads to increase fresh and dry weight, other growth factors and chlorophyll. Application/Improvements: It is concluded that combinations of chelating agents (EDTA and EDDHA) may increase the growth and resistance to soil borne pathogens.

Abiotic reductive extraction of arsenic from contaminated soils enhanced by complexation: Arsenic extraction by reducing agents and combination of reducing and chelating agents

Abiotic reductive extraction of arsenic from contaminated soils was studied with various reducing agents and combinations of reducing and chelating agents in order to remediate arsenic-contaminated soils. Oxalate and ascorbic acid were effective to extract arsenic from soil in which arsenic was associated with amorphous iron oxides, but they were not effective to extract arsenic from soils in which arsenic was bound to crystalline oxides or those in which arsenic was mainly present as a scorodite phase. An X-ray photoelectron spectroscopy study showed that iron oxides present in soils were transformed to Fe(II,III) or Fe(II) oxide forms such as magnetite (Fe3O4, FeIIFe2IIIO4) by reduction with dithionite. Thus, arsenic extraction by dithionite was not effective due to the re-adsorption of arsenic to the newly formed iron oxide phase. Combination of chelating agents with reducing agents greatly improved arsenic extraction from soil samples. About 90% of the total arsenic could be extracted from all soil samples by using a combination of dithionite and EDTA. Chelating agents form strong complexation with iron, which can prevent precipitation of a new iron oxide phase and also enhance iron oxide dissolution via a non-reductive dissolution pathway.

The Effects of Bicarbonate and its Combination with Chelating Agents Used for the Removal of Depleted Uranium in Rats

The effects of bicarbonate and its combination with the chelating agents, deferiprone (L1), 4,6-dimethyl-1-hydroxypyrimidin-2(1H)-one (AK-4), catechol-3,6-bis(methyleneimino-diacetic-acid) (CBMIDA), and ethane-1-hydroxy-1,1-bisphoshonate (EHBP) in removing depleted uranium (DU) for radiation emergency medicine were examined. After the intramuscular injection of DU in rats, various time schedules of bicarbonate and chelating agent administration were tested. The results indicate that the bicarbonate helps increase significantly the effects of LI and AK-4, while there were no effects of using bicarbonate alone. The effects of bicarbonate on CBMIDA were unclear, and the effects of EHBP were negative. Further studies are necessary to obtain distinctly synergic effects by the combination of chelating agents with bicarbonate.

Deposits on soft contact lenses. Electrophoresis and scanning electron microscopic examinations

Deposits on soft contact lenses were studied by several methods, microscopic examination, scanning electron microscopy, electron microprobe and electrophoresis on polyacrylamide gels of removed proteins. The first two approaches permitted classification of deposits into globular deposits, "Mulberry-like growths", opaque deposits, protein films and red spots. The electron microprobe indicated specific compositions of each. The electrophoretic technique demonstrated the presence of lysozyme in all the deposit types, with other unidentified proteins or degradation peptides. Whatever the deposit type, heat disinfection is not advisable since proteins are always present. Combination of chelating agents and oxidizing products are logically to be preferred for cleaning lenses.

体内に沈着したプルトニウムの除去

The chelating agent DTPA (diethylenetriaminepentaacetic acid) is an effective therapeutic substance for the removal of incorporated plutonium. An attempt to review the present knowledge on the subject of removal of incorporated plutonium by chelating agents is made. The efficacy and limitations of DTPA are briefly outlined. The main emphasis is put on; (1) the factors which influence the effectiveness of Ca-DTPA; (2) the local administration of chelating agents at the site of puncture wound; (3) the use of aerosol Ca-DTPA; (4) the efficiency of treatment by pulmonary lavage in vivo; (5) the toxicity of Ca-DTPA; (6) the relative effectiveness of Ca-DTPA and Zn-DTPA.On the basis of the information revealed, the possibilities for an improvement of chelation therapy of internally deposited plutonium are discussed. This can be achieved by the research into (A) the optimum treatment schedule; (B) the removal of plutonium retained in the intracellular space; (C) the possible use of other agents besides Ca-DTPA; (D) the combination of chelating agents and adjuncts to DTPA for removal of plutonium; (E) the efficacy of delayed and long-term therapy on correspondingly lowered incidence of late radiation damage such as osteogenic tumours and lung cancer.