The effect of electrolyte type and amount on color removal by electrocoagulation using iron and aluminium electrodes

The textile dyeing industry is now one of the main sectors and has become one of the most important sources of water pollution. Textile dyeing industry produces a high amount of wastewater. Different dye classes are used in the dyeing process. The dyes used in textile dyeing are organic compounds used for dyeing fabrics or fibers. Textile dyes are very stable in aquatic environment, and biological degradation rates are low. Dyes consist of many toxic substances and can cause some serious harmful effects on the receiving water environment. Due to the color that the waste dye will form in the receiving water environment, the light permeability decreases, and the photosynthesis activities are prevented, and oxygen depletion occurs. Therefore, there is a need for innovative, cost-effective and efficient wastewater enhancement technologies for the treatment of wastewater containing stains before they are released to water systems. It has been observed in the literature that a small number of conventional and biological methods are inadequate for the treatment of wastewater from the textile dyeing industry. The electrocoagulation (EC) process may be a better option for the treatment of such wastewater. In this thesis study, the removal efficiencies of the different classes textile dyes from the water by the electrocoagulation process using aluminum anodes were investigated. The effect of current density treatment efficiency on the electrocoagulation process using aluminum electrodes at anode and cathode was also investigated. For this purpose, Acid (Acid Blue 324), Disperse (Disperse Orange 30), Cationic/Basic (Basic Yellow 28), Vat (Vat Brown 1) and Reactive (Black 5) textile dyes were selected. The dye solutions prepared for the experiments were made to have an electrolyte concentration of 50 mg/l dye and 1000 mg/l NaCl. Experiments were performed with the cut-off system using a 500 ml solution. Electrocoagulation experiments were carried out using an electric coagulation reactor consisting of 3 anodes and 2 cathodes aluminum electrodes, using magnetic stirrer and power supply. In the electrocoagulation process, the influences of current density along with the removal performance of the dyes in different classes were also studied. The recovery efficiencies were found by calculating the dye concentrations from absorbance values measured with UV / Vis spectrophotometer. From the study results; It was observed that the dye class used had an effect on the dye removal by electrocoagulation method. When sorted according to their removal efficiency, the dye class was dispersed, vat, acid, reactive and cationic/basic. At all current densities, the disperse dye was removed from the medium almost entirely with a high removal efficiency, the cationic/basic dye with the worst removal efficiency, but half of the concentration could be removed from the medium.