engleski

REMOVAL OF A MODEL REACTIVE DYE FROM WATER SOLUTION BY ELECTROCOAGULATION

Recently, the removal of pollutants from effluents by electrocoagulation (EC) is becoming an increasingly attractive method because it is a simple and efficient method for the treatment of water and many kinds of wastewater. EC involves the in situ generation of coagulants by electrolytic oxidation of an appropriate sacrificial anode upon application of an electric current ; thereby the generated metal ions produce metal hydroxide. Textile wastewaters are one of the most polluted wastewaters due to their characteristics such as strong color, high pH and temperature and low biodegradability. Dyes in the wastewater present a serious environmental problem since they cut-off sunlight, thereby upset biological activity in aquatic life and destroy aquatic life because of their toxicity. In this work we have investigated the batch removal of the reactive textile dye from an aqueous medium by the electrocoagulation method using iron parallel-connected electrodes. The effects of initial pH, current density and treatment time on the decolorization efficiency have been investigated. Since, the EC process is highly dependent on the conductivity ; NaCl was added in order to enable sufficient initial conductivity of 6.5 mS/cm. The EC process was performed on the solution of the Colored Index (C. I.) Reactive green 8 in water (c = 1 g/L) by applying four different currents. Effectiveness of the EC process for dye removal from water solution was seized by measuring the TOC and the UV/VIS absorbance of water phase obtained by filtration after the process completion. The results showed that there is dependence between the pH and current related to the color removal percent (R.P.%). Hence, in case of I = 1.5 A the R.P. was above 99 % for all applied pH, while in case of I = 0.1 A was between 84 % and 97 % depending on the pH, calculated by measuring UV/VIS absorbance. As expected, when lower currents were applied the required running time was longer. Generally, the effectiveness determined by measuring UV/VIS absorbance was higher than if measuring the TOC ; the difference amounted between 5 % and 15 %.

reactive dye; water solution; removal; electrocoagulation

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