Modeling persulfate activation by iron and heat for the removal of contaminants of emerging concern using carbamazepine as model pollutant

Abstract

A semi-empirical model of heat-activated and iron-activated persulfate (PS) processes applied to the removal of carbamazepine (CBZ) in water at low concentration (0.0025 mM) has been proposed and validated. In heat-activation systems, carried out at pH 3, temperature was varied from 25 °C to 65 °C, and acid-activation of PS showed an important initial role in the process. In iron-activated experimental series, iron concentration was changed from 0.009 mM to 0.18 mM at two different temperatures (25 °C and 35 °C), heat-activation was negligible with iron being the main activation mechanism and acid-activation showing also an important initial effect on process performance. High model prediction capability for both CBZ degradation and PS decomposition profiles was obtained in each case. Finally, the model was validated including supplementary experiments based on Fe(II) additions (0.018 mM each) and PS additions (0.17 mM) throughout the treatment. Developed model in this work is a powerful predictive tool for the application of PS in the removal of contaminants of emerging concern in water.