Source characteristics and gas-particle partitioning of alkylated polycyclic aromatic hydrocarbons in coal combustion emissions

Abstract

Investigations into the characteristics and phase-partitioning behavior of alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) during coal combustion process remain notably limited. This study aims to analyze the source characteristics, distribution patterns, and partitioning mechanisms of parent and alkyl-PAHs in gas and particle phase emissions from coal combustion. The results show that 30.77 %–49.37 % of parent PAHs from coking, gas, lean and fat coal combustion emissions are distributed in gas phases, while it accounts for 78.59 % in lignite coal combustion emission. In terms of alkyl-PAHs, 79.05 %–89.45 % of coking, gas and lean coal combustion emissions are presented in particle phases, and 62.66 %–69.32 % of lignite and fat coal combustion emissions are presented in gas phases. Moreover, the PAH p-values from coal combustion emissions are in the range of −1.00 to −0.68, and the alkylated ones range from −0.80 to −0.54. Interestingly, alkylated phenanthrenes maintain a high degree of uniformity in the distribution patterns of combustion emissions, and their bell-shape distribution pattern performs to be a potential indicator of coal combustion. Furthermore, by employing partitioning models, it can be proven that absorption and adsorption are governing PAH partitioning mechanisms, and alkyl-PAHs can reach equilibrium more rapidly than parent PAHs. These findings offer detailed data into source analysis and the fate of alkyl-PAHs from coal combustion, which is expected to be helpful for environmental behavior investigation and better pollution control of coal combustion.