The removal of Cu (II), Cd (II), Ni (II) and Pb (II) from dilute aqueous solution by a poly(acrylic acid) flocculant and its cross-linked analogue

2002 ◽  
Vol 2 (2) ◽  
pp. 27-34 ◽  
Author(s):  
C. Morlay ◽  
Y. Mouginot ◽  
M. Cromer ◽  
O. Vittori
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Metal Ion ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Conditional Stability ◽  
Complex Species ◽  
Complexing Capacity ◽  
Dilute Aqueous Solution ◽  
Acrylic Acids

The possible removal of copper (II), cadmium (II), nickel (II) and lead (II) from dilute aqueous solution by complexation with poly(acrylic acids) was investigated. The binding properties of two hydrosoluble poly(acrylic acids) of high molecular weight (which make them representative of synthetic flocculants used in the water treatment field; Mw = 2.5 × 105 and 3 × 106 g mol-1) and of an insoluble cross-linked analogue were examined. Potentiometric titrations were carried out, first, to determine the acid-base properties of both polymers and, secondly, to determine the stability constants of the MA and MA2 complex species formed. Metal complexation was also studied using differential pulse polarography. The complexing capacity of each polyacid for the metal ions under study was determined at pH 6.0, 5.0 and 4.0 and the ionic strength was 0.1 or 1.0 mol l-1. The conditional stability constants were estimated assuming that only 1:1 complex species were formed. The results obtained by both methods agree and are complementary. It appeared that stability constants increased in the following order, depending on the metal ion : Ni (II) << Cd (II) < Cu (II) < Pb (II). The hydrosoluble polyacid was able to fix up to 6.3 mmol Pb (II)/g while the insoluble cross-linked analogue was able to fix up to 4.8 mmol Pb (II)/g.

Determination of the complexation properties of a crosslinked poly(acrylic acid) gel with copper(II), nickel(II), and lead(II) in dilute aqueous solution

2001 ◽  
Vol 79 (4) ◽  
pp. 370-376 ◽  
Author(s):  
Catherine Morlay ◽  
Yolande Mouginot ◽  
Monique Cromer ◽  
Olivier Vittori
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Acrylic Acid ◽  
Metal Ion ◽  
Conditional Stability ◽  
Binding Properties ◽  
Complex Species ◽  
Complexing Capacity ◽  
Dilute Aqueous Solution ◽  
Poly Acrylic Acid

The possible removal of copper(II), nickel(II), or lead(II) by an insoluble crosslinked poly(acrylic acid) was investigated in dilute aqueous solution. The binding properties of the polymer were examined at pH = 6.0 or 4.0 with an ionic strength of the medium µ = 0.1 or 1.0 M (NaNO3) using differential pulse polarography as an investigation means. The highest complexing capacity of the polyacid was obtained with lead(II) at pH = 6.0 with µ = 0.1 M, 4.8 mmol Pb(II)/g polymer. The conditional stability constants of the complex species formed were determined using the method proposed by Ruzic assuming that only the 1:1 complex species was formed; for lead(II) at pH = 6.0 and µ = 0.1 M, log K' = 5.3 ± 0.2. It appeared that the binding properties of the polymer increased, depending on the metal ion, in the following order: Ni(II) < Cu(II) < Pb(II). The complexing capacity and log K' values decreased with the pH or with an increase of the ionic strength. These results were in agreement with the conclusions of our previous studies of the hydrosoluble linear analogues. Finally, with the insoluble polymer, the log K' values were comparable to those previously obtained with the linear analogue whereas the complexing capacity values expressed in mmol g-1 were slightly lower.Key words: insoluble crosslinked poly(acrylic acid), copper(II), nickel(II), and lead(II) complexation.

The affinity of aldehydic compounds to complex formation. Nickel(II) and cobalt(II) complexes with 2-pyridinecarboxaldehyde

1977 ◽  
Vol 55 (14) ◽  
pp. 2613-2619 ◽  
Author(s):  
M. S. El-Ezaby ◽  
M. A. El-Dessouky ◽  
N. M. Shuaib
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Metal Ion ◽  
Experimental Conditions ◽  
Complex Species ◽  
Spectrophotometric Methods ◽  
Complex Equilibria ◽  
The Stability ◽  
Hydroxy Groups

The interactions of Ni(II) and Co(II) with 2-pyridinecarboxaldehyde have been investigated in aqueous solutions at μ = 0.10 M (KNO3) at 30 °C. The stability constants of different complex equilibria have been determined using potentiometric methods. Spectrophotometric methods were also used in the case of the nickel(II) – 2-pyridinecarboxaldehyde system. It was concluded that nickel(II) and cobalt(II), analogous to copper(II), enhance hyrdation of 2-pyridinecarboxaldehyde prior to deprotonation of one of the geminal hydroxy groups. Complex species of 1:1 as well as 1:2 metal ion to ligand composition exist under the experimental conditions used.

scholarly journals Interaction of Ampicillin and Amoxicillin with Mn2+: A Speciation Study in Aqueous Solution

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3110
Author(s):  
Claudia Foti ◽  
Ottavia Giuffrè
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Metal Ion ◽  
Formation Constants ◽  
Enthalpy Change ◽  
Ligand Concentration ◽  
Empirical Parameter ◽  
Speciation Study ◽  
Potentiometric Measurements ◽  
The Stability

A potentiometric and UV spectrophotometric investigation on Mn2+-ampicillin and Mn2+-amoxicillin systems in NaCl aqueous solution is reported. The potentiometric measurements were carried out under different conditions of temperature (15 ≤ t/°C ≤ 37). The obtained speciation pattern includes two species for both the investigated systems. More in detail, for system containing ampicillin MLH and ML species, for that containing amoxicillin, MLH2 and MLH ones. The spectrophotometric findings have fully confirmed the results obtained by potentiometry for both the systems, in terms of speciation models as well as the stability constants of the formed species. Enthalpy change values were calculated via the dependence of formation constants of the species on temperature. The sequestering ability of ampicillin and amoxicillin towards Mn2+ was also evaluated under different conditions of pH and temperature via pL0.5 empirical parameter (i.e., cologarithm of the ligand concentration required to sequester 50% of the metal ion present in traces).

Stability constants of metal ion complexes formed with N3-deprotonated uridine in aqueous solution

2003 ◽  
Vol 6 (1) ◽  
pp. 90-93 ◽  
Author(s):  
Bernd Knobloch ◽  
Carla P Da Costa ◽  
Wolfgang Linert ◽  
Helmut Sigel
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Metal Ion ◽  
Metal Ion Complexes

The Extraction of Anionic Beryllium Complexes by Tri-iso-octylamine

1962 ◽  
Vol 15 (3) ◽  
pp. 457 ◽  
Author(s):  
HJ de Bruin ◽  
D Kairaitis ◽  
RB Temple
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Complexing Agents ◽  
Conditional Stability ◽  
Tertiary Amines ◽  
Ph Titration ◽  
Anionic Complexes ◽  
The Stability ◽  
Conditional Stability Constants ◽  
Beryllium Complexes

The extraction of beryllium from aqueous solution by long-chain tertiary amines has been observed in the presence of ligands giving rise to anionic complexes. The nature of the oxalate complex extracted by solutions of tri-iso-octylamine in chloroform has been studied in detail and the species formed in the organic phase were shown to have the composition Be(C2O4)2.{NH(i-C8H15)3}2. The complexes formed in aqueous solution between beryllium and several anionic complexing agents have been examined by the method of pH-titration. Conditional stability constants have been obtained for the complexes formed with oxalic, malonic, maleic, succinic, phthalic, and salicylic acids. Differences in their extractabilities can be explained semiquantitatively with the help of the stability constants and the acid association constants of the complexing agents.

Copper complexation by isatin β-thiosemicarbazones in aqueous solution

1981 ◽  
Vol 34 (12) ◽  
pp. 2549 ◽  
Author(s):  
H Stunzi
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Antiviral Drug ◽  
Copper Electrode ◽  
Water Soluble ◽  
Conditional Stability ◽  
Cupric Ion ◽  
Copper Complexation ◽  
The Stability

The reactions in aqueous solution between cupric ion and water-soluble derivatives of the antiviral drug methisazone (1-methylisatin β-thiosemicarbazone, mibt) have been investigated. Alkalimetric titrations and n.m.r. experiments showed that 5-sulfonatoisatin β-thiosemicarbazone, sibt (3), its 1-methyl derivative, msibt (4), and also p-sulfonatobenzaldehyde thiosemicarbazone, sbat (5), reduce cupric ion and form copper(I) complexes. Stability constants were obtained from measurements of pH and pCu+ on solutions of copper(II) nitrate and excess ligand (I = 0.15 M KNO3, at 37�). The pCu+ values were obtained with an ORION solid state copper electrode. At pH 6-7.5 and moderate excess of ligand, polymeric complexes with an approximate 1 : 1 copper(1)-to-ligand ratio are formed: CunLn or CunLn+,H with n > 6. Monomeric complexes CuL23- predominate at higher pH and in the presence of a more than twentyfold excess of ligand. The stability constants log β2 are 17.9 for sibt, 18.5 for msibt and 19.8 for sbat. At physiological pH (7.4), the order of stability is msibt > sibt & sbat, with conditional stability constants log β2 = 16.2, 15.7 and 13.4, respectively. Comparison with penicillamine shows that some in vivo complexation of copper(I) by methisazone may be possible. On the other hand, a histidinato-copper(II) complex is formed in the presence of histidine.

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