Ali Osman Aydın

Synthesis of a novel dithiooxamide–formaldehyde resin and its application to the adsorption and separation of silver ions

In this study, a new chelating resin of dithiooxamide (rubeanic acid)-formaldehyde (DTOF) has been synthesized by the reaction of dithiooxamide and formaldehyde. Also a well-known chelating resin of thiourea (thiooxamide)-formaldehyde (TUF) has been prepared by the reaction of thiourea and formaldehyde. DTOF and TUF chelating resins were used in the adsorption, separation and concentration of silver ions by batch and column techniques. These resins were characterized using FTIR and elemental analysis. It was found that DTOF resin has silver adsorption capacity of 3333.3 mg g(-1) or 30.86 mmolg g(-1) and TUF resin has the capacity of 1428.6 mg g(-1) or 13.22 mmol g(-1). DTOF resin showed more affinity to silver ions according to Cu(II), Zn(II), Ni(II) and Co(II) base metal ions than TUF resin. It was also demonstrated that DTOF resin can be used in the separation and concentration of silver ions.

Determination of gold, palladium and copper by flame atomic absorption spectrometry after preconcentration on silica gel modified with 3-(2-aminoethylamino)propyl group

A preconcentration method of gold, palladium and copper based on the sorption of Au (III), Pd (II) and Cu (II) ions on a column packed with 3-(2-aminoethylamino)propyl bonded silica gel is described. The modified silica gel was synthesized and characterized by FT-IR and C, H, N elemental analysis. At column preconcentration, the effects of parameters such as pH, volume, flow rate, matrix constituents of solutions and type of eluent on preconcentration of gold, palladium and copper were studied. The recoveries of Au (III), Pd (II) and Cu (II) were 98.93±0.51, 98.81±0.36 and 99.21±0.42 % at 95 % confidence level, respectively. The detection limits (δ) of the elements were 0.032, 0.016 and 0.012 μg ml−1, respectively. The preconcentration method was applied for determination of gold and palladium in certified reference material SARM 7B and copper in river and synthetic seawater by FAAS. Gold, palladium and copper were determined with relative error lower than 10 %.

Determination of heavy metals in roadside soil from Sapanca Area Highway, Turkey

This paper describes the determination of lead and nickel in soil samples from Kinali-Sakarya highway side, near Lake Sapanca. Lake Sapanca is the drinking water source for Sakarya city and its environment. This highway runs between Ankara and Istanbul and carries a heavy traffic volume. Soil samples were taken from different distances from the highway once every two months for a year. Three sampling sites are distinguished, located in areas characterised by heavy traffic volumes but away from industrial pollution sources. In the solutions obtained by dissolving each soil sample, the metals are determined by using flame atomic absorption spectrometry. Lead and nickel concentrations ranged from 0.0 to 47.54 and from 0.0 to 58.67 mg/kg, respectively. Nickel accumulations are lower than the world standard, but lead accumulations are above acceptable limit values. The highest lead levels were observed during September, November and March.

Surfactant-assisted polyol preparation of nickel powders with different morphologies

Sub-micrometer nickel powders of controlled size and morphology were produced by a surfactant-assisted polyol method, using ethylene glycol (EG) as solvent and reductant in the presence of sodium dodecyl sulfate (SDS) surfactant and NaOH. The resultant Ni powders were characterized by XRD, SEM, EDS, and FTIR. Spherical, hexagonal, and triangular fcc Ni powders from 0.30 to 0.60 μm were obtained in the presence of SDS; irregular spherical fcc Ni powders were obtained in its absence. The concentrations of SDS, NaOH and Ni(CH3COO)2·4H2O greatly influence the product morphology and size.

Adsorption of Selenite Ions onto Poly(1,8-diaminonaphthalene) Synthesized by Using Ammonium Persulfate

In the present work, poly(1,8-diaminonaphthalene) (poly(1,8-DAN)) was synthesized by chemical oxidation of 1,8-diaminonaphthalene (1,8-DAN) monomer with ammonium persulfate (APS) oxidant and it was used in the adsorption of selenite ions. The polymer samples synthesized at various molar ratios of 1,8-DAN to APS were characterized by FTIR analysis and they were used in the adsorption experiments. The effects of initial acidity, the molar ratio, and initial selenium concentration on the adsorption behavior of poly(1,8-DAN) were examined by using batch adsorption technique. It was found that selenite was adsorbed onto poly(1,8-DAN) in strong acidic conditions (3-8 M HCl). The experimental adsorption data were applied to the Langmuir and Freundlich isotherms. The adsorption capacities of the polymer samples at the molar ratios of 1/0.5 and 1/2 were calculated as 75.19 and 45.05 mg Se/g, respectively. It was estimated that the adsorption mechanisms of selenite ions onto poly(1,8-DAN) were governed by electrostatic interaction (>NH2+SeOCl3−) and piazoselenol type binding (-N=Se=N-).

Sülfirik Acı İçinde Milas Boksit Cevherinin Çözünürlüğü

The effects of calcination conditions, sulphuric acid concentrations and dissolving temperature and period as parameters to the solubility of the bauxite ore from Gobekdagi reserves in Mugla-Milas region were investigated. The bauxite samples were calcined in different periods at different temperatures. Then the solubility of the calcined bauxite samples in sulphuric acid solution was examined. Dissolving activation energy (Ea) was calculated using the optimum kinetics equation and the results obtained from the solubility studies examined dissolving temperatures and periods