Ultrasonically Activated Persulfate Degrades Typical Odors in Water

Abstract

In order to solve the problem of odor pollution in drinking water effectively, the typical odorants 2-methylisoborneol (2-MIB) and Geosmin (GSM) were selected as target pollutants. The degradation effect and factors influencing these two typical odors by ultrasonically (US) activated persulfate (PS) advanced oxidation technology were systematically investigated in this work. When the sample was treated for 15 min, the application of US/PS combination technology increased the removal rates of 2-MIB and GSM by 57.0% and 63.6%, respectively, compared with sonication alone. Furthermore, the optimum removal rates of 2-MIB and GSM were 88.7% and 93.3% when the 2-MIB and GSM concentrations were 100 ng·L-1. Moreover, the degradation rates of 2-MIB and GSM increased with increasing PS concentration (from 0.25 mmol·L-1 to 2 mmol·L-1) and US intensity (from 0.33 W·cm-2 to 0.53 W·cm-2). The presence of humic acid competes to consume free radicals to inhibit the degradation of odor. The addition of the radical scavengers methanol and tert-butanol can reduce the removal rates of 2-MIB and GSM. The presence of methanol had a stronger inhibition effect on odor degradation than tert-butanol, indicating that the odor removal was mainly caused by sulfate radicals and hydroxyl radicals in the combination US/PS technology.