A Comparison Study of Fenton-like and Fenton Reactions in Dichloromethane Removal.

Abstract

Dichloromethane (DCM) as a low-chlorinated organic compound is hardly to be degraded through reductive dechlorination pathway. In this study, the removal of DCM in Fenton-like system using activated carbon fibers supported zero-valence Fe/Ni nanoparticles (ACF-Fe/Ni) as catalyst was investigated and compared with that of traditional Fenton system (Fe2+/H2O2). The influence of vital parameters including initial solution pH, DCM concentration, catalyst and H2O2 dosages, temperature and cosolute on the removal of DCM was systematically studied. The results showed that 94.2% of DCM with an initial concentration of 5\u2005mg/L could be removed in the Fenton-like reaction under the optimum condition: initial pH of 2.0, 0.4\u2005g/L of ACF-Fe/Ni, 10\u2005mM of H2O2 and temperature of 30°C. In comparison, the removal of DCM in the Fenton-like system was faster than that of the Fenton system and the corresponding activation energies were 39.69 and 33.82 kJ/mol, respectively. The coexistence of solute was adverse to the removal of DCM in the both Fenton-like and Fenton systems. Moreover, the active species for DCM removal in the Fenton-like system was confirmed as hydroxyl radical (·OH) via the quenching experiment and EPR measurement. The incomplete mineralization (41.7%) of DCM after reaction indicated that the Fenton-like technology had a potential to realize DCM non-toxic and harmless conversion and organic intermediates formed needed to take longer to be decomposed.