Study on Analysis of Total Organic Carbon (TOC) and Polycyclic Aromatic Hydrocarbons (PAHs) in Municipal Waste Incinerator Fly Ash and Bottom Ash

Abstract

Studies on the presence of polycyclic aromatic hydrocarbons (PAHs) in Vietnamese incinerator ash samples are relatively limited. In this study, an analytical procedure for the determination of 16 PAHs in fly ash and bottom ash of municipal waste incinerator was investigated. PAHs were extracted from the ash samples by using a focused ultrasonic processor with different solvents including acetone, dichloromethane, and toluene. Among these solvents, toluene exhibited the highest extraction efficiency. The PAH extracts were purified by passing through solid phase extraction cartridges containing silica gel with dichloromethane/hexane (1:3) as elution solvent. PAHs were separated and quantified on a gas chromatography/mass spectrometry (GC/MS) system operated in electron impact ionization (EI) and selected ion monitoring (SIM) mode. Total organic carbon (TOC) contents and total PAH concentrations in the bottom ash were about 6 times higher than those of the fly ash. Levels of PAHs in our ash samples were generally lower than values documented by previous studies in the UK, Sweden, China, and Taiwan. Concentrations and profiles of PAHs in ash samples varied greatly and additional studies on these pollutants in waste incineration activities are needed to characterize their formation mechanism and emission pathway.