Effect of ammonium sulfate and urea on PCDD/F formation from active carbon and possible mechanism of inhibition

Mi Yan , Zhifu Qi , Jie Yang , Xiaodong Li , Jianli Ren , Zhang Xu


Received May 03, 2013,Revised July 22, 2013, Accepted , Available online November 20, 2014

Volume 26,2014,Pages 2277-2282

The effect of ammonium sulfate ((NH4)2SO4) and urea (CO(NH2)2) on polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) formation fromactive carbonwas investigated in this study. Both additives could significantly inhibit PCDD/F formation, and PCDD/F (TEQ) generation was reduced to 98.5% (98%) or 64.5% (77.2%) after 5% (NH4)2SO4 or CO(NH2)2 was added into model ash, respectively. The inhibition efficiency of PCDDs was higher than the value of PCDFs, however, the reduction of PCDD/F yield wasmainly fromPCDFs decreasing. In addition, the solid-phase products were reduced more than the gas-phase compounds by inhibitors. By the measurement of chlorine emission in the phase of ion (Cl[Cl-]) andmolecule gas (Cl[Cl2]), it was observed that both Cl[Cl-] and Cl[Cl2] were reduced after inhibitors were added into ash. Cl[Cl2] was reduced to 51.0% by urea addition, which was supposed as one possible mechanismof PCDD/F inhibition.

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