Amendment of hydroxyapatite in reduction of tetrachloroethylene by zero-valent zinc: its rate enhancing effect and removal of Zn(II).
The effects of hydroxyapatite (HAP) on dechlorination of tetrachloroethylene (PCE) by zero-valent zinc (ZVZ) were examined in batch systems. PCE was primarily transformed to trichloroethylene by ZVZ, with 1,2-trans-dichloroethylene representing a minor product. Dechlorination of PCE was accelerated by the presence of HAP, and the pseudo-first order rate constants increased with increasing amount of HAP. Zn(II), mostly generated from oxidative dissolution of ZVZ by PCE, was effectively removed from the solution by HAP. Ion substitution, coprecipitation, and adsorption are proposed as the possible mechanisms for Zn(II) removal. These reactions appeared to occur simultaneously and the contribution of each reaction to overall removal of Zn(II) was primarily dependent on HAP loading at constant ZVZ loading. The results indicate that the use of HAP in combination with conventional zero-valent metals is promising in that it can achieve both degradation of organic contaminants and stabilization of inorganic contaminants.
Song
Hocheol
H
Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350, South Korea. hsong@kigam.re.kr
Carraway
Elizabeth R
ER
Kim
Young Hun
YH
Batchelor
Bill
B
Jeon
Byong-Hun
BH
Kim
Jae-gon
JG
D017886:Durapatite / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods; D007700:Kinetics; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D013750:Tetrachloroethylene / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D017886:Durapatite; D015032:Zinc; D013750:Tetrachloroethylene