Degradation of Gas-Phase Propylene Glycol Monomethyl Ether Acetate by Ultraviolet/Ozone Process: A Kinetic Study

Abstract

A pilot-scale plug-flow reactor was built to investigate its performance in treating airborne propylene glycol monomethyl ether acetate (PGMEA) via ozonation, ultraviolet (UV) photolysis and UV/O3 technologies. Governing factors, such as the initial molar ratio of ozone (O3) to PG MEA, UV volumetric electric power input, and moisture content in the influent airstream, were investigated. A 1-L batch reactor was used to investigate some photodegradation characteristics of PGMEA in advance. Experiments were conducted at a fixed influent PGMEA concentration of ∼50 ppm and an ambient temperature of 26 °C. A gas space time of 85 sec in the plug-flow reactor was kept for either ozonation or photolysis reaction, whereas a gas space time of 170 sec was used for the UV/O3 degradation.Results show that an initial molar ratio of O3 to PGMEA of >2.91 and an UV volumetric electric input power of 0.294 W/L−1 sufficed to obtain PGMEA decompositions of >90% by UV/O3. Kinetic analyses indicate that all types of PGMEA decomposition are pseudo-first order with respect to its concentration. Moisture content (relative humidity = 15–99%) and UV volumetric electric input power (0.147 and 0.294 W/L-1) were major factors that strongly affect the PGMEA degradation rate.