İrfan Kızılcıklı

Adsorption of fluoride from aqueous solution by acid treated spent bleaching earth

Acid treated spent bleaching earth was studied to assess its capacity for the adsorption of fluoride from aqueous solutions. Adsorption isotherms have been modeled by Langmuir and Freundlich equations and isotherm constants for both isotherms were calculated. The effect of the adsorbent concentration on the adsorption was studied. The dependence of the adsorption of fluoride on the pH of the solution has been studied to achieve the optimum pH-value and a better understanding of the adsorption mechanism. It has been found that maximum adsorption of fluoride from aqueous solutions takes place at pH-value of 3.5. Second-order equation was used to describe the adsorption rate of fluoride and adsorption rate constant was calculated. Intraparticle and mass transfer coefficients were calculated. The influence of addition of the anions on the adsorption of fluoride was also studied to simulate industrial waste waters and the addition of anions decreased the adsorption of fluoride on the acid treated spent bleaching earth (SBE).

Antimicrobial Activity of a Series of Thiosemicarbazones and Their Zn II and Pd II Complexes

Thirty-four thiosemicarbazones andS-alkyl thiosemicarbazones, and some of their ZnII and PdII complexes were obtained and purified to investigate antimicrobial activity. MIC values of the compounds were determined by the disc diffusion method againstEscherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Staphylococcus aureus, S. epidermidis, andCandida albicans. The thiosemicarbazones show antibacterial and antifungal effects in free ligand and metal-complex form. Picolinaldehyde-S-methyl- and -S-benzylthiosemicarbazones did not affect the tested microorganisms but their ZnII complexes showed selective activity. The antimicrobial activity is relatively high in Me2SO, but the antimicrobial potential is changed in a certain range with Me2SO, HCONMe2, EtOH and CHCl3.

Zn(II) and Pd(II) Complexes of Thiosemicarbazone‐S‐alkyl Esters Derived from 2/3‐Formylpyridine

Abstract Representative S‐methyl/ethyl‐4‐H/phenylthiosemicarbazones and their Zn(II) and Pd(II) complexes were synthesized. Characterization of the 1:1 complexes, [Zn(L)Cl2], [Pd(L)Cl2], and [Pd(L)Cl]Cl, was accomplished by means of elemental analyses, IR and 1H NMR spectra. The multidentate S‐alkyl thiosemicarbazones coordinate as mono‐, bi‐, or tridentate ligands depending on the types of the alkyl moiety and metal ion.

Removal of 2,4-D from aqueous solution by the adsorbents from spent bleaching earth.

Abstract The removal of 2, 4‐D (2, 4‐ dichlorophenoxyacetic acid) from aqueous solutions by activated spent bleaching earths (SBE) was studied at 20 °C. Experiments were performed as a function of time, initial concentration, dose and particle size of the adsorbent. The Langmuir and Freundlich adsorption equations were fitted by the adsorption data obtained. The values of Langmuir and Freundlich constants were determined. The adsorption kinetic was found to follow Lagergren equation. Both the boundary layer and intraparticle diffusion played important roles in the adsorption rate of 2, 4‐D. As the size of the adsorbent increased, the time to reach equilibrium increased but adsorption capacity decreased.

Removal of MCPA from Aqueous Solutions by Acid‐Activated Spent Bleaching Earth

The removal of MCPA (4‐chloro‐2‐methyl phenoxyacetic acid) from aqueous solutions by activated spent bleaching earth (SBE) was studied as a function of time, initial concentration, adsorbent concentration, and temperature. The Langmuir and Freundlich isotherms were fitted by the adsorption data obtained. The values of Langmuir and Freundlich constants were determined. The adsorption kinetics was described by the Lagergren equation. Mass transfer coefficient and thermodynamic parameters were also calculated. Column experiments were conducted and brekthrough capacities were found for different concentrations and different flow rates. The study demonstrates that acid‐treated SBE could be used as an efficient adsorbent for the removal of MCPA–bearing wastewater effluents.

Dioxomolybdenum(VI) complexes of 2-hydroxybenzaldehyde 4-phenyl-S-methylthiosemicarbazone

Mixed ligand complexes of dioxomolybdenum(VI) with 2-hydroxybenzaldehyde 4-phenyl-S-methylthiosemicarbazone (H2L) were prepared with the formula [MoO2(L)D] (D = H2O, methyl, n-butyl, and n-undecyl alcohol, DMF, DMSO, pyridine, 4-picoline, and 3,5-lutidine). The compounds were characterized by elemental analysis, IR and 1H NMR spectroscopy. The thermal decomposition of the compounds were investigated by using TGA, DTG, and DTA methods in air, and the thermal behavior depending on the second ligand molecule was discussed. A single crystal of the DMF coordinated complex was studied by X-ray diffractometry.

ACIDITY OF SOME 2-SUBSTITUTED-1HBENZIMIDAZOLES AND THEIR AFFINITY TOWARDS Cu(II) ION

369 INTRODUCTION 370 EXPERIMENTAL 372 Materials and methods 372 Preparation of the 2-substituted-lH-benzimidazole derivatives 372 Potentiometrie titrations 374 RESULTS AND DISCUSSION 376 Solubility of the ligands 376 Protonation constants of the ligands 376 Formation constants of Cu(II) complexes with I-XXVIII 378 REFERENCES 379

2‐Hydroxy‐1‐naphthaldehyde S‐(Alkyl)‐N4‐phenylthiosemicarbazone Complexes with Fe(III), Co(III), Ni(II), and Cu(II) Ions

2‐Hydroxy‐1‐naphthaldehyde S‐(alkyl)‐N4‐phenyl‐thiosemicarbazones (alkyl = CH3, C2H5, n‐C3H7 and C6H5CH2) were synthesized according to common procedures. The 1:1 and 1:2 metal to ligand complexes with Fe(III), Co(III), Ni(II), and Cu(II) salts were synthesized and characterized by analytical data, IR, 1H NMR spectroscopy, magnetic susceptibility, molar conductivity and TGA analysis. It was determined that the tridentate behavior of the ligands is accomplished via the phenolic hydroxy group, the azomethine and thioamide nitrogens.

Dioxomolybdenum(VI) Complexes of 5-Bromo/3,5-Dibromo-Salicylaldehyde 4-(H/C6H5)-S-Propyl-Thiosemicarbazones

GRAPHICAL ABSTRACT Abstract Nine mixed ligand complexes of dioxomolybdenum(VI) with 5-bromo and 3,5- dibromo salicylaldehyde 4-(H/C6H5)-S-propylthiosemicarbazones (H2L) were prepared with the formula [MoO2(L)D] (D = pyridine, methanol, n-propanol or 2-propen-1-ol). Characterization of the compounds was accomplished by means of elemental analysis, IR and 1H NMR spectroscopy, and in one example, a single crystal X-ray structure determination. The dibasic thiosemicarbazone ligands are coordinated to dioxomolybdenum(VI) cation through ONN set, while the sixth coordinated site of the molybdenum is occupied by the second ligand (D). The MoO2 core of the complex is in cis-dioxomolybdenum structure with angles 105.8 Å, the crystal analysis of complex 1a indicated a dimer structure consisted of two 1a molecules by hydrogen bond with 2.054 Á. The decisive roles of S-alkyl groups on the bond lengths of Mo−Npy coordination the intermolecular hydrogen bonds were evaluated.

Palladium(II) complexes of benzaldehyde and 2-hydroxybenzaldehyde-4-H/phenyl- S -ethyl/allyl-thiosemicarbazones

The thiosemicarbazone derivatives R1-C6H4-CH=N-N=(C-S-R2)-NH-R3 [R1 = H, OH; R2 = H, Ph; R3 = C2H5, C3H5] were prepared by a modified general method. The Pd(II) complexes of the thiosemicarbazone ligands LI–VI were isolated in the compositions [Pd(L)Cl2], [Pd(L)Cl] and [Pd(L)2]. The 1: 1 and 1: 2 metal complexes have non-ionic character, and the compounds were characterized by analytical data and infrared and proton resonance spectroscopy. The cis-trans and syn-anti isomers of the thiosemicarbazones were determined by means of 1H NMR, and the coordination behavior of the polydentate thiosemicarbazone ligands towards the palladium ion were discussed.