Ni EDTA Research Articles

Amidoxime-Functionalized Interfacial Microenvironment Reconstruction Promotes Cathodic Nickel Recovery from Ni–EDTA

Amidoxime-Functionalized Interfacial Microenvironment Reconstruction Promotes Cathodic Nickel Recovery from Ni–EDTA

Electrochemical Removal of Ni–EDTA Mediated by Chlorine and Hydroxyl Radicals on BDD Anodes

Electrochemical Removal of Ni–EDTA Mediated by Chlorine and Hydroxyl Radicals on BDD Anodes

Effects of Ni, Fe chemicals and hydrogen on deposits formed on Zirlo fuel cladding material in nuclear primary water chemistry conditions at 325 °C

The morphology and amount of deposits formed on the surface of a Zirlo fuel cladding material were investigated in terms of the concentration of Ni, Fe chemicals and hydrogen after testing using a test loop simulating an AOA, since these deposits can have an influence on an AOA. Porous deposits with some needle-like whiskers were observed after testing in a solution containing 3.5ppm Li as LiOH and 1500ppm B as H3BO3. Ni and Fe acetates were added for this test intermittently to increase the deposits formed on the surface of the fuel cladding material. The pore sizes are from 0.1 to 0.3μm. To minimize the pH change during the tests, Ni EDTA and Fe EDTA were used in the same solution instead of Ni and Fe acetates. Polyhedral structures were found, when both of Ni EDTA and Fe EDTA coexist significantly. These polyhedral structures are nickel ferrites analyzed by SEM–EDS. A number of whiskers with about a 0.05μm diameter were detected, when the ratio of Ni/Fe increased due to decrease of Fe concentration during the test, even though the initial Fe concentration was high. However, some short whiskers are formed, when initial Ni concentration was high. These whiskers seem to be NiO by SEM–EDS. It was reported that the formation of fine whiskers might be one of the major causes for an AOA in connection with SNB. These whiskers were observed, when the hydrogen concentrations were 5 and 25cc/kg H2O in the test conditions at 325°C. No whiskers were found in the conditions at above 25cc H2/kg H2O. In addition, it was found that the concentration of hydrogen does not greatly affect the amount of deposit formed on the surface during testing.

Degradation of Ni–EDTA complex by Fenton reaction and ultrasonic treatment for the removal of Ni2+ ions

It is difficult to meet the increasingly stringent environmental regulations by the application of conventional precipitation processes treating complex heavy metal wastewaters. We studied the potential of a new method for removing heavy metals from metal–EDTA wastewater by Fenton reaction followed by hydroxide precipitation. This process is referred to as Fenton reaction-hydroxide precipitation (FR-HP) process. This study investigated the use of FR-HP and ultrasonic/FR-HP processes for the removal of Ni(II) from Ni–EDTA wastewater. The results indicate that ultrasonic/FR-HP process is more effective for the removal of nickel ions than FR-HP process.

Influence of variable chemical conditions on EDTA-enhanced transport of metal ions in mildly acidic groundwater

Adsorption of Ni and Pb on aquifer sediments from Cape Cod, Massachusetts, USA increased with increasing pH and metal-ion concentration. Adsorption could be described quantitatively using a semi-mechanistic surface complexation model (SCM), in which adsorption is described using chemical reactions between metal ions and adsorption sites. Equilibrium reactive transport simulations incorporating the SCMs, formation of metal-ion–EDTA complexes, and either Fe(III)-oxyhydroxide solubility or Zn desorption from sediments identified important factors responsible for trends observed during transport experiments conducted with EDTA complexes of Ni, Zn, and Pb in the Cape Cod aquifer. Dissociation of Pb–EDTA by Fe(III) is more favorable than Ni–EDTA because of differences in Ni- and Pb-adsorption to the sediments. Dissociation of Ni–EDTA becomes more favorable with decreasing Ni–EDTA concentration and decreasing pH. In contrast to Ni, Pb–EDTA can be dissociated by Zn desorbed from the aquifer sediments. Variability in adsorbed Zn concentrations has a large impact on Pb–EDTA dissociation.

Ion Spray Mass Spectrometry for Elemental Speciation in Aqueous Samples: Preliminary Investigation of Experimental Parameters, Matrix Effects and Metal–Ligand Complexation

Ion spray mass spectra obtained from aqueous solutions are discussed. Ion clusters with large numbers of water molecules, very few water molecules or bare elemental ions could be obtained by adjusting the sampling orifice voltage, the skimmer voltage or the position of the ion spray nebulizer relative to the sampling orifice. In some cases submillimeter changes in the position of the ion spray nebulizer can dramatically affect the nature of the spectra observed. There is evidence of declustering between the skimmer and first ion lens as well as between the sampling orifice and skimmer. Interpretation of the mass spectra must be carried out with care as potential spectral overlaps are common. Use of a triple quadrupole mass spectrometer allows assessment of potential spectral overlaps. Ni–EDTA complexation was investigated. The Ni + signal correlated with the expected concentration of free metal ions in the solution not the total metal concentration even when relatively harsh conditions that produced bare metal ion spectra were used. Matrix effects due to high concentrations of NaCl and HCl were briefly investigated.

Copper and nickel tolerance in Typha latifolia clones from contaminated and uncontaminated environments

Plants of Typha latifolia L. derived from overwintering rootstocks collected from a site contaminated with copper and nickel and an uncontaminated control location were maintained in the laboratory for a minimum of three vegetative generations. Uptake of copper and nickel by both clones from contaminated nutrient solutions was greater than from control solutions. Growth of both clones was inhibited by 100 μg g−1 Cu–EDTA, and 600 μg g−1 Ni–EDTA. Evidence suggesting that copper and nickel tolerance has evolved in the population from the contaminated site could not be detected. Indeed clones from the uncontaminated site showed greater growth under copper stress than clones from the contaminated site, while growth of both clones was equally depressed under conditions of nickel stress.