title: Efficient dechlorination of carbon tetrachloride by hydrophobic green rust intercalated with dodecanoate anions.
abstract: The reductive dechlorination of carbon tetrachloride (CT) by Fe(II)-Fe(III) hydroxide (green rust) intercalated with dodecanoate, Fe(II)(4)Fe(III)(2)(OH)(12)(C(12)H(23)O(2))(2) · yH(2)O (designated GR(C12)), at pH ~ 8 and at room temperature was investigated. CT at concentration levels similar to those found in heavily contaminated groundwater close to polluted industrial sites (14-988 μM) was reduced mainly to the fully dechlorinated products carbon monoxide (CO, yields >54%) and formic acid (HCOOH, yields >6%). Minor formation of chloroform (CF), the only chlorinated degradation product, was also detected (yields <6.3%). Reactions carried out with excess GR followed pseudo first-order kinetics with respect to CT with rate constants ranging from 6.5 × 10(-2) to 0.47 h(-1). These rate constants are comparable to those measured for CT dechlorinations mediated by zerovalent iron. Reduction of the highest concentration of CT (1.4 mM) proceeds until 56% of the Fe(II) sites of GR(C12) was consumed. This reaction ceased after 10 h due to surface passivation of GR(C12).
authors.affiliation: Department of Basic Sciences and Environment, University of Copenhagen , Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark. kayala@life.ku.dk
authors.forename: Karina B
authors.initials: KB
authors.lastname: Ayala-Luis
authors.forename: Nicola G A
authors.initials: NG
authors.lastname: Cooper
authors.forename: Christian Bender
authors.initials: CB
authors.lastname: Koch
authors.forename: Hans Christian B
authors.initials: HC
authors.lastname: Hansen
mesh_terms: D002248:Carbon Monoxide / Q000737:chemistry; D002251:Carbon Tetrachloride / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D005561:Formates / Q000737:chemistry; D007700:Kinetics; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D005290:Ferric Compounds; D005296:Ferrous Compounds; D005561:Formates; D014874:Water Pollutants, Chemical; C030544:formic acid; D002713:Chlorine; D002248:Carbon Monoxide; D002251:Carbon Tetrachloride