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THERMAL TREATMENT OF 1,2,3,4-TETRACHLORODIBENZO-P- DIOXIN BY REACTION WITH CA-BASED SORBENTS AT 23-300 DEGREES °C
Citation:
Gullett*, B K., D. Natschke, AND K. Bruce. THERMAL TREATMENT OF 1,2,3,4-TETRACHLORODIBENZO-P- DIOXIN BY REACTION WITH CA-BASED SORBENTS AT 23-300 DEGREES °C. ENVIRONMENTAL SCIENCE & TECHNOLOGY 31(7):1855-1862, (1997).
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The fate of combustion-generated polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans captured in sorbent-based, air pollution control devices remains uncertain. This process was simulated by passing vapor-phase 1,2,3,4-tetrachlorinated dibenzo-p-dioxin (TCDD) to a fixed-bed reactor laden with, typically, 1 g of calcium (Ca)-based sorbent. The sorbent bed, reactor rinsate, evaporation chamber, and gas impingers were analyzed separately to balance and account for the TCDD input. Tests at 160-300E C demonstrated 50 to 100% conversion of TCDD to higher molecular weight, chlorinated products with both aromatic and aliphatic components. The unlikeliness of conventional semivolatile GC/MS analyses to detect these higher molecular weight products may offer an alternative explanation for research studies citing destruction or volatilization of chlorinated organics in the presence of Ca-based sorbents. The applicability of this reaction to other halogenated organics, such as polychlorinated biphenols, may provide a method for contaminated soil treatment. More extensive experimental and analytical work is necessary to fully understand the reaction mechanism, the full range and stability of potential reaction products, and the ecological and human health implications. Alteration of the structural symmetry and size of the TCDD molecule (and related halogenated organics) will likely cause significant reductions in toxicity.
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THERMAL TREATMENT OF 1,2,3,4-TETRACHLORODIBENZO-P- DIOXIN BY REACTION WITH CA-BASED SORBENTS AT 23-300 DEGREES °C (PDF, NA pp, 471 KB, about PDF)