Tevfik Atalay

Transport of Formic Acid Through Anion Exchange Membranes by Diffusion Dialysis and Electro‐Electro Dialysis

Abstract In this study, first, the diffusion dialysis method was used for the transport of formic acid through anion exchange membranes (polysulfone SB‐6407, Neosepta AFN, ACM, and AMH). The transport of formic acid was carried out at different concentration ranges and quantified with the membrane mass‐transfer coefficient and diffusion coefficient parameters. Neosepta AFN and SB‐6407 membranes were efficient for formic acid transport by the diffusion dialysis method at low concentrations. The second method, electro‐electro dialysis was applied as a function of some parameters, such as concentration ratio and polarization curves at constant flow rate (1.17 × 10−6 m3 s−1), and at 0.1‐M concentration of formic acid. In this method, AMH membrane was found to be effective due to its higher mechanical stability, lower proton leakage, lower water content and higher current efficiency.

Thermodynamic studies of some complexes of 4′-morpholinoacetophenone thiosemicarbazone

Abstract Ni(II), Cu(II), Ag(I) and Hg(II) form 1:2 (metal—ligand) complexes with 4′-morpholinoacetophenone thiosemicarbazone. The stability constants of these complexes in 60% (v/v) aqueous DMF were determined at different ionic strengths (0.07, 0.13 and 0.20 M) and at different temperatures (25, 30, 35 and 40 ± 0.1°C) using a spectrophotometric method. From these constants, the thermodynamic stability constants and thermodynamic parameters (Δ G ⊖ , Δ H ⊖ , Δ S ⊖ ) were calculated.

Evaluation of thermodynamic parameters and stability constants of Cu(II), Ag(I) and Hg(II) complexes of 2-methylindole-3-carboxaldehyde thiosemicarbazone

Abstract The stability of Cu(II), Ag(I) and Hg(II) complexes of 2-methylindole-3-carboxaldehyde thiosemicarbazone have been determined using a spectrophotometric method in 50% (v/v) aqueous ethanol at different ionic strengths (0.12, 0.22 and 0.4 M) and at different temperatures (25, 30, 35 and 40 ± 0.1°C). For each metalligand system at each temperature, the thermodynamic stability constant (In K θ) was obtained graphically at zero ionic strength from plots of In K versus ionic strength. The thermodynamic parameters were evaluated from plots of In K θ versus 1/ T .

Thermodynamic stabilities. Thermodynamic parameters of some complexes of 4′-morpholinoacetophenone 4-phenyl-3-thiosemicarbazone

Abstract The stability constants (ln K ) of the Co(II), Ni(II), Cu(II), Ag(I), Cd(II) and Hg(II) complexes with 4′-morpholinoacetophenone 4-phenyl-3-thiosemicarbazone were determined using a spectrophotometric method at different temperatures (25, 30, 35 and 40 ± 0.1°C) and at different ionic strengths (0.05, 0.10 and 0.20 mol dm −3 ) in 60% (v/v) aqueous dimethylformamide. Plots of thermodynamic stability constants at zero ionic strength (ln K 0 ) versus T −1 gave linear curves, and Δ H θ and Δ S θ were also calculated from these plots. Moreover, the changes in free energy for each metal—ligand system were calculated from the equation Δ G θ = − RT ln K 0 .

Kinetic study of copper(II) complexation with 9-ethyl-3-carbazolecarboxaldehyde-thiosemicarbazone and kinetic-spectrophotometric determination of copper(II)

The kinetics of complexation reaction of Cu(II) with 9-ethyl-3-carbazolecarboxaldehyde-thiosemicarbazone (ECCAT) has been examined spectrophotometrically. The ligand was synthesized for the first time. The complexation reaction was carried out in a DMF-water medium at 35°C. The complex has maximum absorbance at 393 nm. Kinetic and activation parameters of the complexation reaction were calculated by the Arrhenius and Eyring equations using the data obtained from investigating the effect of temperature on reaction rates under the specified conditions. We also proposed reaction rate equations. Based on the studied complexation reaction, a simple kinetic method for the spectrophotometric determination of copper(II) has been developed. The calibration graphs are linear in the concentration range 0.2–1.9 μg/mL. The species that caused interference were investigated.

Comparison of Commercial Anion‐Exchange Membranes for Pickle Waste Treatment by Electro‐Electrodialysis

Abstract This study deals with recovery conditions of acids from the pickle waste of leather industry by applying of electro‐electrodialysis process. The pickle waste consists of NaCl, HCOOH, H2SO4, and organic dirt. The four commercial anion exchange membranes (Neosepta AFN, ACM, AMH, and Polysulfone SB‐6407) have been used and the necessary specific energies for recovering conditions as well as the most appropriate membranes were determined. In the laboratory‐scale experiments, AMH anion‐exchange membrane has the best combination of electrochemical, mechanical properties and high ion permselectivity. On the contrary, AFN membrane showed good performance with respect to other membranes used and it has the lowest necessary specific energy. In this method, HCl was also produced from its salt during the recovering process.

Interfacial transfer of Cd2+ assisted by 4′ — morpholino-acetophenone-4-phenyl-3-thiosemicarbazone across the water/1,2-dichloroethane interface

AbstractThe assisted transfer of heavy metal ions by interfacial complexation with 4′-morpholinoacetophenone-4-phenyl-3-thiosemicarbazone (MAPPT) at the interface between two immiscible electrolyte solutions (ITIES) was studied by cyclic voltammetry. The voltammograms obtained across the water/1,2-dichloroethane interface using the MAPPT ligand in the organic phase shows that the assisted metal ion transfers have different nature for different ions. The quasi-reversible voltammetric peak of the Cd2+ ion was obtained and is discussed in detail. The dependence of the half-wave transfer potential on MAPPT concentration showed that the equilibrium is effectively displaced towards a 1:3 (metal:ligand) stoichiometry with an association constant of log βo =15.46 (±0.11) for the Cd2+ ion, corresponding to the TIC/TID mechanism.

Determination of thermodynamic parameters of some complexes of 2-methylindole-3-carboxaldehyde 4-phenyl-3-thiosemicarbazone

Abstract Cobalt(II), Ni(II), Cu(II) and Hg(II) form 1:2 (metal-ligand) complexes with 2-methyl-indole-3-carboxaldehyde 4-phenyl-3-thiosemicarbazone. The stability constants of these complexes in 60% (v/v) aqueous DMF were determined at different ionic strengths (0.10, 0.20 and 0.40 M KNO 3 ) and of 25, 30, 35 and 40°C (±0.1°C) using a spectrophotometric method. From these constants, the thermodynamic stability constants and thermodynamic parameters ΔG θ , ΔH θ and ΔS θ were calculated.