Dechlorination of polychlorinated biphenyls (PCBs) in water matrix using UV/H2O2

• Main Authors: Centeno, Carmel R., Tolentino, Elaine Nicolas, Abella, Leonila C., Gallardo, Susan M.
• Format: text
• Published: Animo Repository 2005
• Subjects: Dechlorination; Polychlorinated biphenyls; Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/13356
• Institution: De La Salle University

This study presents the results of GC-mass spectrophotometric analysis of the formation of reaction intermediates or products during the degradation of polychlorinated biphenyls (PCBS) using the UV/H2O2 system. Simulated PCB contaminated water solution was subjected to irradiation with 10 watt, 254 nm wavelength UV lamp in a batch tubular reactor. Ratio of oxidant to PCBs (in terms of Aroclor 1260) was based on 2,500 µL H₂O₂ is to 40ppm PCB. Samples were extracted from the matrix by solid-phase extraction (SPE) method using C18 cartridges with hexane and ethyl acetate as solvents. Samples were analyzed using Gas Chromatography-Electron Capture Detector System (GC-ECD) to determine the concentrations of PCBs in the samples and pH was monitored every sampling time. The analysis of chloride (CI) ion concentration in the samples was done using Argentometric titration. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis showed that Aroclor 1260 contained highly chlorinated biphenyls penta-, hexa-, hepta-, and octachlorobiphenyls. Determination of reaction intermediates and products was also carried out. Since a decrease in pH in the early stages of degradation was observed, dechlorination must have been the main mechanism during the first few minutes of the reaction. Analysis of inorganic chloride ions concentration verified this observation. GC-MS results also show that the oils and waxes containing the PCBs were also degraded but PCB degradation was favored during the first few minutes of the reaction.