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The removal of chemical oxygen demand (COD) from landfill leachate by electro-coagulation (EC) using iron sacrificial anode has been investigated. The process performance is analyzed in terms of COD removal efficiency and the important costrelated parameters such as electrode and energy consumptions, as a function of initial pH, conductivity, current density, and operation time. The optimum COD removal (65.85%) was obtained with typical operating conditions: current density, 30 mA/cm 2 ; operation time, 180 min; conductivity, 16.4 ms/cm; and initial pH, 6.54. At these conditions, the electrode and energy consumptions during the electrolysis were determined as 0.418 kg COD/kg Al and 11.092 kWh/kg COD, respectively. In addition, the EC and Fenton processes are applied together referred to as the electro-Fenton process in the literature for the removal of COD from landfill leachate and effect of operation time and hydrogen peroxide concentration is examined. The process was very fast in the first 15 min, and then it slowed down till it was complete in 60 min. An optimum COD removal efficiency of 74.21% was obtained at 5000 ppm hydrogen peroxide dosage and 60 min.

In this study, surfactant-modified zeolite (SMZ) was used to remove Remazol Brillant Blue R and Remazol Yellow reactive dyes from aqueous solutions. The influences of suspension pH, temperature, agitation rate, and the SMZ dosage on reactive dyes removal and adsorption capacity were investigated by conducting a series of batch adsorption experiments. The adsorption kinetics was tested for pseudo-firstorder, pseudo-second order, intraparticle diffusion model, Elovich, and Bangham models, and rate constants of the kinetic models were calculated. Equilibrium isotherms for the adsorption of reactive dyes were analyzed by the Freundlich, Langmuir, Dubinin-Radushkevich, and Tempkin isotherm models. The Langmuir monolayer adsorption capacities of Remazol Brillant Blue R and Remazol Yellow were estimated as 13.9 and 38.31 mg/g, respectively. The adsorption rate was rapid; more than half of the adsorbed Remazol Brillant Blue R was removed in the first 60 min and of Remazol Yellow in the first 30 min. Thermodynamic parameters such as DH 0 , DS 0 , and DG 0 , at 208C, were found to be 5.2126 kJ/mol, 0.0273 kJ/mol K, and 22.7969 kJ/mol (Remazol Brillant Blue R), and 29.9747 kJ/mol, 0.10875 kJ/mol K, and 21.8900 kJ/mol (Remazol Yellow), respectively.

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In this study, the decolorization of Levafix Brilliant Blue E-B by electrocoagulation method using aluminum and iron electrodes was investigated. The influence of the operating variables such as current density, initial pH, time of electrolysis, supporting electrolyte concentration on decolorization efficiency, and energy consumption was determined. The results show that aluminum electrode (Al) was more effective than iron (Fe) electrode in terms of decolorization efficiencies and operating costs. When the aluminum electrode was used, 99% decolorization was obtained at current density of 100 A/ m 2 , initial pH of 5.5, electrolyte concentration of 5 mM, and electrolysis time of 20 min. The corresponding energy consumption and operating cost were found as 16.9 kWh/m 3 and 2.921 $ per m 3 , respectively.

Electrodeposition is an attractive method used for the recovery and removal of metal ions from metal coatings, metal processing and electronic industry wastes. In this study, copper was both removed and recovered from industrial wastewater containing copper by using the electrodeposition method. Two series of experiments were conducted by using copper and stainless steel as cathodes. In both experiments, the effects of current, pH, conductivity and initial copper concentration on the electrodeposition efficiency were investigated, and optimum values were obtained. With this method, the amount of copper removed from industrial wastewater under optimum conditions was 66% in the experiments conducted with the copper cathode and 80% in the experiments conducted with the stainless steel cathode. It was also observed as a result of the experiments that the copper removed from the wastewater was deposited on the cathode. In addition, reaction kinetics suitable for the experimental conditions were investigated and generally found to be compatible with a second-order kinetic model.