Efficient remove methylparaben by ozonation process

This study aimed to analyze the factors affecting the degradation of methylparaben solution by ozonation process. Kinetic studies on methylparaben degradation were carried out under different operating conditions, such as ozone concentration, initial pH values of the solution, methylparaben concentration and temperature. Complete degradation was achieved after 15 min of reaction using the methylparaben concentration of 30 mg L −1 at pH 9, 30 mg L −1 dosages of ozone and 20 °C. Methylparaben degradation by ozonation followed the pseudo-first-order kinetic model. The rate of methylparaben degradation increased when increasing pH from 3 to 9 and with the increased concentration of ozone applied. For the best condition, the model predicted an apparent reaction rate constant equal to 0.21 min −1 . In addition to the application of the ozonation, ozone-combined processes were studied under the optimal conditions obtained for ozonation. The tested processes were ozonolysis and heterogeneous photocatalytic ozonation. The most efficient method for the degradation and mineralization was photocatalytic ozonation, reaching mineralization rates higher than 93% in 90 min of reaction. Furthermore, in vivo tests using methylparaben solutions previously treated by ozonation and photocatalytic ozonation confirmed there was no toxicity.