Enhanced Dechlorination of 1,2-Dichloroethane by Coupled Nano Iron-Dithionite Treatment

• DOI: 10.1021/acs.est.6b00734
• Publication Date: 2016-04-29T16:43:10Z
• Authors: Ariel Nunez Garcia; Hardiljeet K. Bop...; Denis M. O’Carroll
• Keywords: Zerovalent iron; Dithionite; Reductive Dechlorination; Reactivity; Tetrachloroethylene

1,2-Dichloroethane (1,2-DCA) is a chlorinated solvent classified as probable human carcinogen. Due to its extensive use in industrial applications, widespread contamination, and recalcitrance toward abiotic dechlorination, 1,2-DCA remains challenging compound for the remediation community. Over past decade, nano zerovalent iron (nZVI) has been efficiently used treat many of compounds concern. However, thus far, even nZVI (monometallic or bimetallic) unable dechlorinate 1,2-DCA. Therefore, an alternative treatment coupling with dithionite proposed this work. Coupled nZVI-dithionite was able degrade >90% over course year. The effects loadings, carboxymethyl cellulose (CMC) coating, addition palladium, other species metal surfaces on degradation kinetics were also investigated. Observed pseudo-first-order rate constants (kobs) ranged from 3.8 × 10(-3) 7.8 d(-1). Both nucleophilic substitution reductive dechlorination are mechanisms by coupled treatment. Characterization analysis nanoparticles shows that most still preserved state after more than one year reactivity some sulfide (FeS) formation. Scanning electron microscopy (SEM) nanosized spherical particles present along FeS platelets. This novel represents first nZVI-based formulation achieve nearly complete