Osman Akba

Polymer Supported Humic Acid for Separation and Preconcentration of Thorium(IV)

Abstract The resin impregnating humic acid (HA) onto XAD‐4 has been prepared to investigate adsorption behaviour of Th(IV). The characterization of the resulting resin has been carried out by infrared spectral data and sorption capacity. Maximum adsorption capacity of Th(IV) on the resin is found to be 1.51 × 10−4 mol g−1 at pH 4. The sorbent was found to possess a high selectivity for Th(IV) with an optimum extraction pH around 3–7. Recoveries for Th(IV) determined prior to breakthrough were found to be quantitative (96–99%). The resin exhibits good chemical stability, reuseability, and a faster rate of equilibration for Th(IV) determination. The influence of several ions as interferents is discussed. The method has been successfully applied for the separation of Th(IV) in synthetic mixtures.

The accumulation and histological effects of organometallic fungicides Propineb and Maneb in the kidneys of fetus and female rats during pregnancy.

Dithiocarbamate propineb and maneb are organometal fungicides, which are widely used for the control of diseases in plants. Female Wistar rats were exposed orally to 200 and 400 ppm propineb and 250 ppm maneb, from the sixth day of gestation up to birth. We found that the body weights of both one-day old litters and their fungicide-treated mothers were lower than those of controls. Histological examination of the kidneys of fetus and fungicide-treated pregnant females showed a variety of histopathological effects. Moreover, the analysis of zinc (Zn) and manganese (Mn) concentrations (using inductively coupled plasma-atomic emission spectrometry) in the kidneys of pregnant females exposed to organometallic fungicides during pregnancy demonstrated that the metal concentrations in the kidney were higher than those of controls. However, the renal metal concentrations were significantly increased in the litters subjected to the fungicides during gestation, indicating that high levels of the trace metals in the organ of fetus may well be due to the fungicides easily passing the placental barrier.

Synthesis of Esters Under Microwave Irradiation Using Heteropoly Acids as Catalysts

A practical and simple technique for synthesis of esters was developed by using heteropoly acid as catalyst under microwave irradiation in the absence of organic solvents. Alcohols were easily and selectively converted to their acetates and benzoates with excellent yields (≥98%), and in very short time (∼5 min), as environmentally benign.

Preparation, Spectroscopic Investigation and Characterization of Molybdovanadophosphoric Acid and Its Complexes with N,N′-Diethylaniline

Abstract Free H4[PMo11VO40]. 32 H2O (molybdovanadophosphoric acid) was prepared re-producibly as an orange-red crystaline solid. The N,N′-diethylaniline complexes of the molybdovanadophosphoric acid were prepared and investigated for the first time. Various colored complexes were obtained depending on the solvents used and conditions.

Preparation and Characterization of Polyoxometallates of Molybdenum, Tungsten and Their Salts

Abstract In this work, confirmation of the molecular formula and investigation of the structural stability of the prepared various types of heteropoly acids and their salts by TGA are reported. Specific surface areas of the samples were determined by the BET-single point N2 adsorption method. Scanning electron microscopy (SEM) was used for the of surface topography of the samples in the sense of crystalline and amorphous states and the acidities of these solid samples were determined based on the color changes of suitable indicator solutions by the way of a butylamine titration method. Impurities, weight ratios and bonding states of the characteristic elements of the samples were determined from XRD, EDX and FTIR studies. Referee I: S. H. Wasfi Referee II: V. N. Joshi