Removal of telon red A2R dyeing from aqueous solutions by electrooxidation method

Urbanization and developments in industry have brought about change and complexity in discharged wastewater. Increasing chemical types cause difficulties in purification. Chemicals and dyestuffs that are difficult to treat generally originate from the pharmaceutical, food, leather, cosmetic and textile industries. One of the industrial types in which dyestuffs are used the most is textile. Wastewater must be treated appropriately before discharge to receiving environments for the environment and human health. In particular, textile industry wastewater with high color, COD, BOD contents can cause aesthetic concern in water, decrease photosynthetic activities by reducing light transmission, damage the ecosystem, and have serious toxicity and carcinogenic effects for human and environmental health. Conventional treatment methods have been insufficient for pollutants such as textile wastewater with high pollution, which has led to a tendency towards advanced treatment methods. Advanced oxidation processes based on hydroxyl radical formation are gaining more and more importance day by day. Removal of hard to decompose and toxic organic compounds that are made easily degradable or to end products such as CO2 and H2O can be achieved by advanced oxidation processes. The disadvantages of electrochemical oxidation, one of the advanced oxidation processes, are that it can form pollutants and is expensive. In this study, the results obtained in the electrochemical oxidation of the dye called Telon Red A2R, which is used in the textile industry, by using the Boron Doped Diamond (BDD) electrode, were optimized to the surface response method (YYM) with the Box-Behnken design. In the study, the effects of pH, electrolysis time and current density on the removal efficiency of color, and TOK were investigated. In the model created, optimum conditions were found to be pH 4, current 0.75 A and time 116 min for 96% color removal efficiency, and optimum conditions pH 5, current 1.25 A and time 57 min for 77% TOK removal efficiency. When the fit of the model used was examined, the predicted R2 for color removal was 0.7767, the corrected R2 was 0.9065, the predicted R2 for TOC removal was 0.3250 and the corrected R2 was 0.4728. Since the difference in both is less than 0.2, they are in reasonable agreement. Considering the results, it has been observed that the increase in pH, current density and electrolysis time brings with it an increase in color and TOC removal efficiencies. However, due to insufficient mineralization for TOC removal, expected removal efficiencies could not be obtained. Therefore, longer electrolysis times and higher currents are required.