Dechlorination of trichloroethylene formed from 1,1,2,2-tetrachloroethane by dehydrochlorination in Portland cement slurry including Fe(II).
Transformation of 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA) by Fe(II) in 10% cement slurries was characterized using a batch reactor system. 1,1,2,2-TeCA was completely converted to trichloroethylene (TCE) within 1h in all experiments, even in controls with cement that did not include Fe(II). Therefore, complete degradation of 1,1,2,2-TeCA depends on the behavior of TCE. The half-life of TCE was observed to be 15d when concentrations of Fe(II) and 1,1,2,2-TeCA were 98mM and 0.245mM, respectively. The kinetics of TCE removal was observed to be dependent on Fe(II) dose, pH and initial substrate concentration. Pseudo-first-order rate constants linearly increased with Fe(II) dose up to 198mM when initial target concentration was 0.245mM. Pseudo-first-order kinetics generally described the degradation reactions of TCE at a specific initial concentration, but a modified Langmuir-Hinshelwood model was necessary to describe the degradation kinetics of TCE over a wide range of initial concentrations. A surface reaction of TCE on active solids, which were formed from Fe(II) and products of cement hydration appears to control observed TCE degradation kinetics.
Jung
Bahngmi
B
Department of Earth and Environmental Sciences, Wright State University, Dayton, OH 45435, USA. jung.bahngmi@gmail.com
Batchelor
Bill
B
D003252:Construction Materials; D004980:Ethane / Q000031:analogs & derivatives* / Q000737:chemistry; D005296:Ferrous Compounds / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009922:Oregon; D010084:Oxidation-Reduction; D014241:Trichloroethylene / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D005296:Ferrous Compounds; D006843:Hydrocarbons, Chlorinated; D014867:Water; C015530:1,1,2,2-tetrachloroethane; D014241:Trichloroethylene; D004980:Ethane