Effect of Hydrochloric Acid on Sampling and Analysis of Semivolatile Organic Compounds in Incineration Flue Gas. 4. Polychlorinated Dibenzo-p-dioxins and Polychlorinated Dibenzofurans

Abstract

At constant concentrations of moisture (14%), carbon dioxide (7%), and oxygen (10%), hydrochloric acid (0.17-5.53 mg/L) in incineration flue gas does not affect the recoveries of tetrachloro to octachloro congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The mean recoveries of PCDDs/PCDFs from XAD-2 of MM5 train are 87-114% with relative standard deviations of 5-15%. Liquid-liquid extraction recoveries of PCDDs from the synthetic condensates containing 0.051 and 1.88 M HCl are 99±8% and 88±10%, respectively, and are not dependent on the number of chloro substituents. However, PCDFs recoveries from the condensate containing 1.88 M HCl increases from 82% for tetrachlorodibenzofuran to 103% for octachlorodibenzofuran. Without pH adjustment, the recoveries of PCDDs and PCDFs from the combined acidic condensate and ethylene glycol are 100±12% and 98±9%, respectively. The addition of a strong base for pH adjustment of highly acidic combined liquid leads to lower PCDDs/PCDFs recoveries (60-84%). A comparison of the acid effects on PCDDs/PCDFs and on other semivolatile organic compounds is briefly discussed.