Meral Turabik

Adsorption of basic dyes from single and binary component systems onto bentonite: simultaneous analysis of Basic Red 46 and Basic Yellow 28 by first order derivative spectrophotometric analysis method.

The present study deals with the simultaneous analysis and adsorption of Basic Yellow 28 and Basic Red 46 dyes in binary mixture onto bentonite. First order derivative spectrophotometric method was used for simultaneous analysis of BY28 and BR46 in binary mixtures. The adsorption experiments were carried out in a batch system. The mono- and multi-component Langmuir and Freundlich isotherm models were applied to experimental data and the isotherm constants were calculated for BY28 and BR46 dyes. The monolayer coverage capacities of bentonite for BY28 and BR46 dyes in single solution system were found as 256.4 mg/g and 333.3mg/g, respectively. It was observed that the equilibrium uptake amounts of BY28 and BR46 dyes in binary mixture onto bentonite decreased considerably with increasing concentrations of the other dye resulting in their antagonistic effect. The adsorption equilibrium data fitted more adequately to mono-component Langmuir isotherm model than mono-component Freundlich isotherm model, while the extended Freundlich isotherm model adequately predicted the multi-component adsorption equilibrium data at moderate ranges of concentration. Thermodynamic parameters showed that adsorption of BR46 and BY28 was endothermic and spontaneous in nature.

Photocatalytic degradation of Basic Red 46 and Basic Yellow 28 in single and binary mixture by UV/TiO2/periodate system

The present study deals with the investigation of photocatalytic degradation and mineralization of C.I. Basic Red 46 (BR46) and C.I. Basic Yellow 28 (BY28) dyes in single and binary solutions as a function of periodate ion concentration (IO(4)(-)), irradiation time, initial pH and initial dye concentrations. First order derivative spectrophotometric method was used for to simultaneous analysis of BY28 and BR46 in binary mixtures. Langmuir-Hinshelwood kinetic model was applied to experimental data and apparent reaction rate constant values were calculated. The apparent degradation rate constant values of BR46 were higher than those of BY28 for all experiments in single dye solutions. On the other hand, the significant reductions were observed for the apparent degradation rate constant values of the BR46 in the presence of BY28 in binary solutions whereas TOC removal efficiency slightly enhanced in binary system. The highest TOC removal efficiency was obtained at pH 3.0 by adding 5mM periodate ion in to the solution in the presence of 1g/L TiO(2) for both dye solutions. After 3h illumination, 68, 76 and 75% mineralization were found for 100mg/L BY28, 100mg/L BR46 and 50+50mg/L mixed solutions, respectively.

Electrocoagulation and nanofiltration integrated process application in purification of bilge water using response surface methodology

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box-Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5-15 V), initial pH (4.5-8.0) and time (30-90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P > 0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R(2) and Radj(2) values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R(2) values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage-time and pH-time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect.

Competitive Biosorption of Acid Dyes from Binary Solutions onto Enteromorpha prolifera: Application of the First Order Derivative Spectrophotometric Analysis Method

The biosorption of Acid Red 274 and Acid Red 337 dyes from single and binary solutions on Enteromorpha prolifera was investigated in a single stage batch system. The first order derivative spectrophotometry was tested in order to analyse the studied binary solutions of the selected dyes. The single- and multi-component Langmuir and Freundlich isotherm models were applied to the experimental equilibrium data and the isotherm parameters were estimated. It was observed that the uptake amounts of the first component decreased with increasing concentration of the second component from binary solution. As a result, the binary biosorption of AR274 and AR337 dyes on E.prolifera have an antagonistic effect. The binary biosorption of AR274 and AR337 dyes in a single stage batch system was modelled and the equilibrium concentrations of the exit stream were found by using the experimental equilibrium curves and operating lines for the biosorption of single and binary dye solutions.

Effect of synthesis parameters on the particle size of the zero valent iron particles

ABSTRACT It is known that synthesis conditions significantly affect the particle size. The sizes of particles also affect the particles efficiency. In this study, because of its importance as a material, the effect of synthesis parameters on the particle size of zero valent iron particles such as initial ferric iron concentration, initial borohydride concentration, initial stabilizer concentration, temperature, initial pH, NaBH4 adding rate, and stirring rate were examined in detail. The results showed that the initial ferric iron and borohydride concentrations used in the synthesis primarily affected the particles sizes of zero valent iron. Also high temperature values showed a negative effect in producing small particles.