TY - JOUR
T1 - Comparative electrochemical treatments of two chlorinated aliphatic hydrocarbons. Time courseof the main reaction by-products
AU - Randazzo, Serena
AU - Scialdone, Onofrio
AU - Randazzo, Serena
AU - Sirés, Ignasi
AU - Brillas, Enric
PY - 2011
Y1 - 2011
N2 - Acidic aqueous solutions of the chlorinated aliphatic hydrocarbons 1,2-dichloroethane (DCA) and 1,1,2,2-tetrachloroethane (TCA) have been treated by the electro-Fenton (EF) process. Bulk electrolyses were performed at constant current using a BDD anode and an air diffusion cathode able to generate H2O2 in situ, which reacts with added Fe2+ to yield •OH from Fenton’s reaction. At 300 mA, almost total mineralization was achieved at 420 min for solutions containing 4 mM of either DCA or TCA. Comparative treatments without Fe2+ (anodic oxidation) or with a Pt anode led to a poorer mineralization. The better performance of the EF process with BDD is explained by the synergistic action of the oxidizing radicals, BDD(•OH) at the anode surface and •OH in the bulk, and the minimization of diffusional limitations. The decay of the initial pollutant accomplished with pseudo first-order kinetics. Chloroacetic and dichloroacetic acids were the major by-products during the degradation of DCA and TCA, respectively. Acetic, oxalic and formic acids were also identified. The proposed reaction pathways include oxidative and reductive (cathodic) dechlorination steps. Chlorine was released as Cl, being further oxidized to ClO3 and, mostly, to ClO4, due to the action of the largely generated BDD(•OH) and •OH.
AB - Acidic aqueous solutions of the chlorinated aliphatic hydrocarbons 1,2-dichloroethane (DCA) and 1,1,2,2-tetrachloroethane (TCA) have been treated by the electro-Fenton (EF) process. Bulk electrolyses were performed at constant current using a BDD anode and an air diffusion cathode able to generate H2O2 in situ, which reacts with added Fe2+ to yield •OH from Fenton’s reaction. At 300 mA, almost total mineralization was achieved at 420 min for solutions containing 4 mM of either DCA or TCA. Comparative treatments without Fe2+ (anodic oxidation) or with a Pt anode led to a poorer mineralization. The better performance of the EF process with BDD is explained by the synergistic action of the oxidizing radicals, BDD(•OH) at the anode surface and •OH in the bulk, and the minimization of diffusional limitations. The decay of the initial pollutant accomplished with pseudo first-order kinetics. Chloroacetic and dichloroacetic acids were the major by-products during the degradation of DCA and TCA, respectively. Acetic, oxalic and formic acids were also identified. The proposed reaction pathways include oxidative and reductive (cathodic) dechlorination steps. Chlorine was released as Cl, being further oxidized to ClO3 and, mostly, to ClO4, due to the action of the largely generated BDD(•OH) and •OH.
KW - 1
KW - 2
KW - 2-Dichloroethane; Electrochemical water treatment technologies; Electro-Fenton; Organochlorinated pollutants; Reaction pathway; 1
KW - 2-Tetrachloroethane.
KW - 1
KW - 2
KW - 2-Dichloroethane; Electrochemical water treatment technologies; Electro-Fenton; Organochlorinated pollutants; Reaction pathway; 1
KW - 2-Tetrachloroethane.
UR - http://hdl.handle.net/10447/60621
M3 - Article
VL - 192
SP - 1555
EP - 1564
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
SN - 0304-3894
ER -