Serkan Bayar

Adsorption of Ni(II) on ion exchange resin: Kinetics, equilibrium and thermodynamic studies

This article describes the ion exchange of a heavy metal Ni(II) from aqueous solutions onto a Dowex HCR-S, cationic resin. Batch adsorption studies were conducted to evaluate the effect of various parameters such as pH, resin dose, stirring speed, temperature, contact time and initial Ni(II) concentration on the removal of Ni(II). Adsorption rate increased with the increase in initial nickel concentration, stirring speed and temperature. Equilibrium adsorption isotherms were measured for the single component system, and the experimental data were analyzed by using Langmuir, Freundlich, Elovich, Temkin, Khan, Sips, Toth, Koble-Corrigan and Radke-Prausnitz isotherm equations. The Sips equation appears to fit the equilibrium data. Different models were tested for their applicability. Adsorption kinetic data were modeled using the Lagergren pseudo-first-order, Ho’s pseudo-second-order and Elovich models. It was found that Ho’s pseudo-second-order model could be used for the prediction of the system’s kinetics. Thermodynamic activation parameters such as ΔG*, ΔS* and ΔH* of the adsorption of Ni(II) on Dowex HCR-S cationic resin were also calculated.

Investigation of adsorption of the dyestuff astrazon red violet 3rn (basic violet 16) on montmorillonite clay

In this study, color removal by absorption from synthetically prepared wastewater was investigated using montmorillonite clay by adsorption. As dyestuff Astrazon Red Violet 3RN (Basic Violet 16) was used. Experimental parameters selected were pH, temperature, agitation speed, initial dyestuff concentration, adsorbent dosage and ionic strength. It was established that adsorption rate increased with increasing pH, temperature, dye concentration and agitation speed, but decreased with increased ionic strength and adsorbent dosage. Adsorption equilibrium data obtained by a series of experiments carried out in a water bath were employed with common isotherm equations such as Langmuir, Freundlich, Temkin, Elovich and Dubinin-Radushkevich. It was found that the Langmuir equation appears to fit the equilibrium data better than the other models. Furthermore, the fit of the kinetic data to common kinetic models such as the pseudo-first-order, second-order, Elovich and intraparticle diffusion models was tested to elucidate the adsorption mechanism. Kinetic data conformed to the pseudo-second-order model, indicating chemisorptions. In addition, the thermodynamic parameters activation energy, Ea, enthalpy ΔH*, entropy, ΔS*, and free energy change, ΔG*, were calculated. The values of the calculated parameters indicated that physical adsorption of ARV on the clay was dominant and that the adsorption process was endothermic.

Effects of operational parameters on cadmium removal from aqueous solutions by electrochemical coagulation

Abstract The aim of present study is to investigate the feasibility of cadmium removal from water using electrocoagulation. Electrocoagulation (EC) is an electrochemical wastewater treatment technology with increased popularity and considerable technical improvements. In the study, effects of operating parameters such as initial solution pH, initial concentration (C 0), reaction time (t), stirring speed, and conductivity (κ) on cadmium removal from synthetic wastewater-containing cadmium in the batch electrocoagulation process were investigated. It was found from experimental results that initial solution pH is important parameter affecting cadmium removal. pH of initial solution was in the range of 3 to 6 in the experiments. The largest cadmium removal efficiency was obtained with pH 6. pH 6, obtained from initial solution whose pH was 6, reached an agreement with activity to pH diagrams for Al+3 species in equilibrium with Al(OH)3. Although specific energy consumption increased with decreasing cadmium c...

The effect of initial pH on treatment of poultry slaughterhouse wastewater by electrocoagulation method

AbstractIn this work, treatment of poultry slaughterhouse wastewater by electrocoagulation method with aluminum plate electrodes has been investigated. System was operated in batch and galvonostatic mode. Effect of initial pH of the wastewater was predominantly investigated on chemical oxygen demand (COD) removal efficiency but turbidity and oil–grease removal efficiencies were also evaluated. Operational parameters were kept constant at 150 rpm of stirring speed, 1 mA/cm2 of current density, and 293 K of solution temperature. On the other hand, initial pH of the wastewater was in the range of 2–8. Initial pH of the wastewater was an effective parameter on COD removal efficiency as it is expected. When initial pH of the wastewater was in the range from 3 to 4, it was possible to obtain higher COD removal rates. In this study, when the initial pH of wastewater equals to 3 and current density is 1 mA/cm2, system gives COD removal efficiency of 85% in 20 min. Meanwhile, system consumes 2.14 kWh/m3 of energy ...

Pre-Treatment of Pistachio Processing Industry Wastewaters (PPIW) by Electrocoagulation using Al Plate Electrode

The objective of the present study is to assess the efficiency of electro-coagulation treatment of pistachio processing industry wastewaters (PPIW) using an aluminum plate electrode. The effect of some of the parameters was examined on the removal of chemical oxygen demand (COD), total organic carbon (TOC), and total phenols (TP) removal efficiency. The treatment was carried out in a batch system. The influences of current density (from 1 to 6 mA cm−2), initial pH of wastewater (from 2 to 8), constant pH of wastewater (from 3 to 7), stirring speed (from 100 to 500 rpm), and supporting electrolyte concentration (from 10 to 50 mg L−1 NaCl) on removal efficiency were investigated to determine the best experimental conditions. The evaluation of the physico-chemical parameters during the treatment by electrocoagulation showed that the best removal efficiency was obtained under the conditions of 180 min electrolysis time, wastewater with constant pH of 6, and 6 – mA cm−2 current density. Under such experimental conditions, COD, TOC, and TP removal efficiency were found to be 60.1%, 50.2%, and 77.3%, respectively, while energy consumption was 39.6 kW-h m−3. The results of the study show that the electrocoagulation can be applied to PPIW pre-treatment.

Boron removal by means of chemical precipitation with calcium hydroxide and calcium borate formation

Boron removal was investigated by chemical precipitation from aqueous solutions containing boron using calcium hydroxide. pH, initial boron concentration, amount of Ca(OH)2, stirring speed and solution temperature were selected as operational parameters in a batch system. The highest boron removal efficiency was reached at pH 1.0. Increasing initial boron concentration and amount of calcium hydroxide raised to boron removal efficiency. Boron removal efficiency was highest at a stirring speed of 150 rpm. The most important parameter affecting boron removal efficiency was solution temperature. Increasing solution temperature increased importantly boron removal. XRD analysis showed that CaB3O3(OH)5·4H2O, which is a borate mineral called inyoite, occurred between Ca(OH)2 and borate ions. As a result of the obtained experimental data, when the optimum operational conditions were selected, over 96% of boron removal efficiency was reached by this method.