Inhibition of phenol entering condensed freshwater by activated peroxides during photothermal distillation desalination process

Abstract

The formation of “high-temperature, high-salt and intense-light” environment during the new process of photothermal distillation desalination causes volatile pollutants such as phenol in seawater to volatilize into condensed freshwater, resulting the quality safety risk of the freshwater. In this work, activated peroxides processes including hydrogen peroxide (H2O2), peroxyacetic acid (PAA), peroxodisulfate (PDS) and peroxymonosulfate (PMS) were applied for the inhibition of phenol entering condensed freshwater by making full use of the “high-temperature, high-salt, intense-light” media. Under the same conditions, the phenol removal efficiency by the activated peroxides were in the order of H2O2 < PDS < PAA < PMS. The effects of the salinity, peroxide dosage, initial phenol concentration, humic acid and sunlight intensity on the distillation rates (RD) of phenol were investigated. It was revealed that the main factor for activation of H2O2, PAA, PDS and PMS were heat, Cl−/heat, heat/light and Cl−, respectively. Though both PMS and PAA could completely degrade phenol and reduced its entry into condensed freshwater, PMS formed fewer halogenated distillation by-products and was more promising for future applications.