Cathodic hydrogen as electron donor in enhanced reductive dechlorination

Ruiling Zhang, Xiaoxia Lu, Danny D. Reible, Gangzhen Jiao, Songyan Qin

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

In situ capping is an attractive and cost-effective method for remediation of contaminated sediments, but few studies on enhancing contaminant degradation in sediment caps have been reported, especially for chlorinated benzenes. Electrically enhanced bioactive barrier is a new process for in situ remediation for reducible compounds in soil or sediments. The primary objective of this study is to determine if electrodes in sediment could create a redox gradient and provide electron acceptor/donor to stimulate degradation of chlorinated contaminant. The results demonstrate that graphite electrodes lead to sustainable evolution of hydrogen, displaying zero-order kinetics in the initial stages with different voltages. The constant rates of hydrogen evolution at 3, 4, and 5 V are 1.05, 2.54, and 4.3 nmol·L-1·d -1, respectively. Even higher voltage can produce more hydrogen, but it could not keep long time because the over potentials on electrode surfaces prevent its function. The study shows that 4 V is more appropriate for hydrogen evolution. The measured and evaluated concentration of 1,2,3,5- tetrachlorobenzene in pore water of sediment and concentration of sulfate show that dechlorination is inhibited at higher concentration of sulfate.

Original languageEnglish
Pages (from-to)1386-1390
Number of pages5
JournalChinese Journal of Chemical Engineering
Volume21
Issue number12
DOIs
StatePublished - Dec 2013

Keywords

  • capping
  • dechlorination
  • electrode
  • hydrogen
  • reductive

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