scholarly journals Metal Ion Selectivity of Kojate Complexes: A Theoretical Study

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Sarita Singh ◽  
Jyoti Singh ◽  
Sunita Gulia ◽  
Rita Kakkar
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Density Functional ◽  
Ion Selectivity ◽  
Divalent Metal Ions ◽  
High Energies ◽  
Square Planar ◽  
Metal Ion Selectivity ◽  
Carbonyl Bond ◽  
Complexation Reactions

Density functional calculations have been performed on four-coordinate kojate complexes of selected divalent metal ions in order to determine the affinity of the metal ions for the kojate ion. The complexation reactions are characterized by high energies, showing that they are highly exothermic. It is found that Ni(II) exhibits the highest affinity for the kojate ion, and this is attributed to the largest amount of charge transfer from the ligand to the metal ion. The Ni(II) complex has distorted square planar structure. The HOMOs and LUMOs of the complexes are also discussed. All complexes display a strong band at ~1500 cm−1 corresponding to the stretching frequency of the weakened carbonyl bond. Comparison of the complexation energies for the two steps shows that most of the complexation energy is realized in the first step. The energy released in the second step is about one-third that of the first step.

scholarly journals STUDY OF REMOVAL OF METAL IONS IN WATER USING ZEOLITES SYNTHESIZED WITH CHARCOAL ASHES

2006 ◽  
Vol 05 (3) ◽  
pp. 21-30
Author(s):  
Denise Alves FUNGARO ◽  
Juliana de Carvalho IZIDORO
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Ion Selectivity ◽  
Coal Ash ◽  
Electroplating Effluent ◽  
Zeolitic Material ◽  
Equilibrium Data ◽  
Metal Ion Selectivity ◽  
Removal Of Metal ◽  
Removal Of Metal Ions

The capacity of synthesized zeolites from Brazilian coal ash for the removal of metal ions from aqueous solutions has been investigated. Equilibrium data obtained have been found to fit both the Langmuir and Freundlich adsorption isotherms. The zeolitic material prepared with coal ash from baghouse filter showed the highest removal efficiencies. The metal ion selectivity of this product was determined as: Pb2+ > Cd2+ > Cu2+ > Zn2+ > Ni2+. The maximum cation exchange capacities were between 32.9 and 246.9 mg g-1. Tests showed that the zeolitic material was suitable for removal of zinc from electroplating effluent.

scholarly journals Modeling of neotame and fructose thermochemistry: Comparison with mono and divalent metal ions by Computational and experimental approach

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Deepali Sharma ◽  
Suvardhan Kanchi ◽  
Ayyappa Bathinapatla ◽  
Inamuddin ◽  
Abdullah M. Asiri
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Density Functional ◽  
Divalent Metal ◽  
Basis Set ◽  
Hydroxyl Groups ◽  
Specific Cell ◽  
Water Medium ◽  
Artificial Sweetener ◽  
Divalent Metal Ions

AbstractThe metal complexes can demonstrate various interesting biological activities in the human body. However, the role of certain metal ions for specific cell activities is still subject to debate. This study is aimed at comparing the thermochemical properties of neotame (artificial sweetener) and α, β-fructose in gas phase and water medium. The interaction of α and β-fructose, neotame with monovalent and divalent metal ions was studied and comprehended by density functional theory (DFT) using B3LYP functional, 6–311 + G (d, p) and D3 basis set. Metal ion affinities (MIA) values depicted that ionic radius of metal ions played an important role in the interaction of α, β-fructose and neotame. The ∆G parameter was calculated to predict and understand the interaction of metal ions with α and β-fructose, neotame. The results suggested that the presence of hydroxyl groups and oxygen atoms in sugar molecules acted as preferred sites for the binding and interaction of mono and divalent ions. For the first time computational study has been introduced in the present study to review the progress in the application of metal binding with sugar molecules especially with neotame. Moreover, voltammetric behaviour of neotame-Zn2+ was studied using cyclic and differential pulse voltammetry. The obtained results suggest that the peak at −1.13 V is due to the reduction of Zn2+ in 0.1 M phosphate buffer medium at pH 5.5. Whereas, addition of 6-fold higher concentration of neotame to the ZnCl2.2H2O resulted in a new irreversible cathodic peak at −0.83, due to the reduction of neotame-Zn2+ complex. The Fourier transform infrared spectroscopy (FTIR) results indicates that the β-amino group (-NH) and carboxyl carbonyl (-C = O) groups of neotame is participating in the chelation process, which is further supported by DFT studies. The findings of this study identify the efficient chelation factors as major contributors into metal ion affinities, with promising possibilities to determine important biological processes in cell wall and glucose transmembrane transport.

scholarly journals Host–Guest Extraction of Heavy Metal Ions with p-t-Butylcalix[8]arene from Ammonia or Amine Solutions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Md. Hasan Zahir ◽  
Shakhawat Chowdhury ◽  
Md. Abdul Aziz ◽  
Mohammad Mizanur Rahman
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Ion Selectivity ◽  
Ammonia Solution ◽  
Ethylene Diamine ◽  
Variation Method ◽  
Extraction Behavior ◽  
Metal Ion Selectivity

The capacities of the p-t-butylcalix[8]arene (abbreviated as H8L) host to extract toxic divalent heavy metal ions and silver from aqueous solution phases containing ammonia or ethylene diamine to an organic phase (nitrobenzene, dichloromethane, or chloroform) were carried out. When the metal ions were extracted from an aqueous ammonia solution, the metal ion selectivity for extraction was found to decrease in the order Cd2+> Ni2+> Cu2+> Ag+> Co2+> Zn2+. When the aqueous phase contained ethylene diamine, excellent extraction efficiencies of 97% and 90% were observed for the heavy metal ions Cu2+ and Cd2+, respectively. Under the same conditions the extraction of octahedral type metal ions, namely, Co2+ and Ni2+, was suppressed. The extraction of transition metal cations by H8L in ammonia and/or amine was found to be pH dependent. Detailed analysis of extraction behavior was investigated by slope analysis, the continuous variation method, and by loading tests.

Properties of the mammalian and yeast metal-ion transporters DCT1 and Smf1p expressed in Xenopus laevis oocytes

2001 ◽  
Vol 204 (6) ◽  
pp. 1053-1061 ◽  
Author(s):  
A. Sacher ◽  
A. Cohen ◽  
N. Nelson
Keyword(s):  
Xenopus Laevis ◽  
Metal Ions ◽  
Metal Ion ◽  
Divalent Cations ◽  
Ion Uptake ◽  
Xenopus Laevis Oocytes ◽  
Ion Transporters ◽  
Divalent Metal Ions ◽  
Transport Pathway ◽  
Metal Ion Uptake

Transition metals are essential for many metabolic processes, and their homeostasis is crucial for life. Metal-ion transporters play a major role in maintaining the correct concentrations of the various metal ions in living cells. Little is known about the transport mechanism of metal ions by eukaryotic cells. Some insight has been gained from studies of the mammalian transporter DCT1 and the yeast transporter Smf1p by following the uptake of various metal ions and from electrophysiological experiments using Xenopus laevis oocytes injected with RNA copies (c-RNA) of the genes for these transporters. Both transporters catalyze the proton-dependent uptake of divalent cations accompanied by a ‘slippage’ phenomenon of different monovalent cations unique to each transporter. Here, we further characterize the transport activity of DCT1 and Smf1p, their substrate specificity and their transport properties. We observed that Zn(2+) is not transported through the membrane of Xenopus laevis oocytes by either transporter, even though it inhibits the transport of the other metal ions and enables protons to ‘slip’ through the DCT1 transporter. A special construct (Smf1p-s) was made to enhance Smf1p activity in oocytes to enable electrophysiological studies of Smf1p-s-expressing cells. 54Mn(2+) uptake by Smf1p-s was measured at various holding potentials. In the absence of Na(+) and at pH 5.5, metal-ion uptake was not affected by changes in negative holding potentials. Elevating the pH of the medium to 6.5 caused metal-ion uptake to be influenced by the holding potential: ion uptake increased when the potential was lowered. Na(+) inhibited metal-ion uptake in accordance with the elevation of the holding potential. A novel clutch mechanism of ion slippage that operates via continuously variable stoichiometry between the driving-force pathway (H(+)) and the transport pathway (divalent metal ions) is proposed. The possible physiological advantages of proton slippage through DCT1 and of Na(+) slippage through Smf1p are discussed.

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