Interaction between zero-valent iron and hydrogen in anaerobic degradation of tetrachloroethylene

The study demonstrates that both hydrogen gas and zero-valent iron enhance the process of anaerobic dechlorination of tetrachloroethene (PCE) in an anaerobic mixed culture. Experimental results show that the addition of iron powder not only increases the degradation of PCE but also reduces the formation of chlorinated intermediates. Ethene is the major end product, while either cisdichloroethlene or vinyl chloride is under the detection limit for all processes. The pseudo-first-order rate coefficients are 0.037, 0.048 and 0.078 d-1 for anaerobes alone, Fe0 alone, and for the combination of zero valence iron and anaerobes, respectively. However, the interaction effect on PCE degradation between anaerobes and iron is insignificant. The half-velocity constant of hydrogen-utilizingdechlorination for PCE is estimated to be 47 ppmv in this system. © 2012, Chinese Institute of Environmental Engineering. All rights reserved.