Optimization of crystal violet dye degradation in aqueous solution by the fenton process with ferrite prepared from iron mining tailings

Dyes and their wide application in clinical analysis laboratories and teaching experimental microbiology are of great environmental concern due to the high volume of wastewater produced and the inefficiency of conventional treatment methods. The present study was carried out to verify the possibility of using the produced ferrite from iron mining waste in the degradation of the crystal violet dye used in the Gram staining technique, an alternative treatment to the conventional ones to avoid the disposal of effluents in laboratories in the environment. To identify the best conditions of ferrite mass and hydrogen peroxide concentration, a design of experiments named Central composite rotatable design (CCRD) was used. According to the results presented by the response surface, at the best conditions of hydrogen peroxide and ferrite mass found by the experimental design correspondent to 400 mg L^-1 and 20 mg, respectively, 93% of the crystal violet dye was degraded during 60 minutes of reaction. Therefore, the results presented in this work are crucial and describe the basic fundaments for understanding the main phenomena that occur in this system, which enables the realization of future investigations for evaluating the industrial application of this system. (author)