Application of the central composite design to mineralization of olive mill wastewater by the electro/FeII/persulfate oxidation method
Gözmen, Belgin | Görmez, Özkan | Yabalak, Erdal
The olive mill wastewater is a major environmental problem, which is waiting for effective treatment. In this study, the mineralization of olive mill wastewater was investigated using the electro/FeII/persulfate process. The central composite design was utilized to examine the effect of each experimental variables (concentration of persulphate and FeII, treatment time and constant current) on the mineralization of olive mill wastewater. The optimum chemical oxygen demand removal percentage was obtained as 71.2% where the reaction conditions were 200 mA current, 250 mM persulphate, 25 mM FeII, and 6 h reaction time. In addition, the maximum percentage of total phenolic removal and the energy consumption were 88% and 4.50 kWh/kgCOD, respectively, which were obtained at the same reaction ...
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
The molecular structure and vibrational spectra of N-(3-tert-butyl-2-hydroxybenzylidene)-2,6-diphenyl-4-hydroxyaniline
Erdal Yabalak | Funda Günay | Hakan Arslan
The molecular structure, vibrational frequencies and intensities of N-(3-tert-butyl-2-hydroxybenzylidene)-2,6-diphenyl-4-hydroxyaniline were calculated by the Density Functional Theory methods (BLYP, B3PW91 and B3LYP) using the 6-31G(d,p) basis set. The calculated geometric parameters were compared to the corresponding X-ray structure of the title compound. The comparison of the theoretical and experimental geometry of the title compound shows that the X-ray parameters fairly well reproduce the geometry of optimized by B3LYP method (r = 0.9825). The harmonic vibrations computed for this compound by the B3LYP/6-31G(d,p) method are in good agreement with the observed IR and Raman spectral data. The root mean square values error of the observed and calculated IR bands are found to be 9.80, 9....
The solubility of sebacic acid in subcritical water using the response surface methodology
Gözmen, Belgin | Görmez, Özkan | Yabalak, Erdal | Gizir, Ahmet Murat
The solubility of sebacic acid in subcritical water was investigated. Response surface methodology was used to study the combined effects of the different parameters such as temperature, static and dynamic time to optimize the process conditions for the maximum solubility of sebacic acid. Solubility results of sebacic acid were observed to be highly correlated with quadratic model according to analysis of variance. The solubility of sebacic acid was found as 500 g L-1 in the optimum conditions at 400 K temperature, 4 min dynamic time and 28 min static time. Approximation models were employed for determining solubility of sebacic acid at elevated temperatures.
Subcritical and supercritical fluid extraction of heavy metals from sand and sewage sludge
ERDAL YABALAK, AHMET MURAT GIZIR
Demetalization of Pb, Ni, Zn, Cu and Cr heavy metal ions from sea sand and real samples of sewage sludge by subcritical water and supercritical carbon dioxide was investigated. Experimental parameters such as temperature, pressure, extraction time in the static and dynamic mode and sampling were optimized in order to determine the suitable conditions for high removal of metals. The best extraction efficiencies were obtained using acetyl acetonate as a chelating agent in both subcritical water and supercritical CO2 extractions for real and artificial samples. Samples collected from extraction system using both subcritical water and supercritical carbon dioxide were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The highest recoveries obtained from real samples for Cr, Cu...