Application of response surface method to optimize the removal of reactive black 5 using Fe (VI)

Today, the rapid development of industries and the use of hundreds of new chemical compounds in them have led to the creation of huge amounts of industrial wastewater, the discharge of which into the environment, especially watercourses, has caused severe pollution. The discharge of colored wastewater into natural ecosystems has created serious risks such as carcinogenesis, mutagenicity, etc. for aquatic life due to adverse functions. Meanwhile, Reactive Black 5 has many industrial applications, especially in the textile industry worldwide. Fe (VI) was synthesized electrochemically using iron and steel electrodes in potassium hydroxide solution at 65 ° C and then used to remove the reactive Black 5 in the batch removal system. In this study, the surface response method (RSM), the effect of various parameters including initial color pH, Fe (VI) dose and time and then the central composite design (CCD) were used to find the best removal conditions. The optimal values for the three variables of pH, Fe (VI) dose and time were obtained 4.5, 24.5 mg and 25 minutes, respectively. In the present study, by increasing the Fe (VI) dose and after 25 minutes from the start of the reaction, the removal efficiency increased, if the removal was better in acidic conditions than in alkaline conditions. Also, under the optimal conditions of Fe (VI) solution, it was able to remove 97% of reactive black 5. Finally, under the same conditions, real wastewater was also worked on and the removal rate was 95%. The findings of this study showed that Fe (VI) can be used as a suitable, inexpensive and high-performance oxidizing agent in the removal of reactive Black 5 from textile industry effluents.