Kinetics on the decomposition of polychlorinated biphenyls with activated carbon-supported iron

Abstract: The process of destroying polychlorinated biphenyls (PCBs) generates exhaust gases that contain low quantities of PCBs, which cannot be disposed of easily. Activated carbon (AC) can be used to adsorb residual PCBs after disposal of high-level PCBs. We examined the chemical reactivity of AC-supported iron as a catalyst to decompose PCB-153, and varied three decomposition parameters (temperature, time and iron concentration) under an atmosphere of either air or N2. We measured the Brunauer–Emmett–Teller (BET) surface area and pore volume of AC to assess the adsorption capacity of AC before and after decomposition. At low temperatures the adsorption process was more important than the decomposition process. The decomposition process was completed within 30 and 60min under air and N2, respectively. The efficiency of PCB-153 decomposition at 350°C for 120min was ∼100.0% and 97.1% under air and N2, respectively. Analysis of inorganic chloride ions revealed that PCB-153 was effectively destroyed during decomposition. The differences between decomposition under air and N2 reflected differences in BET surface and pore volume. [Copyright &y& Elsevier]