Arsenic leachability and speciation in cement immobilized water treatment sludge

Chuanyong Jing, Suqin Liu, Xiaoguang Meng

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

Arsenic leachability and speciation in cement immobilized water treatment sludge were investigated with leaching tests and X-ray absorption near edge structure (XANES) spectroscopy. The As leachability in the sludge determined with the toxicity characteristic leaching procedure (TCLP) and the waste extraction test (WET) was 283 and 7490 μg l-1, respectively. Extractions with a lower liquid to solid ratio, under anaerobic conditions, and using citric acid buffer solution dramatically increased the leachate As concentration. XANES results showed that the As(III) composition was reduced from 51.1% of the total As content in the sludge to 16.3% in the cement treated sample with 28 days of cure. When the cement treated sample was cured for two years, the As(III) composition was decreased to 7.4%. The cement treatment reduced the As leachability. The leachate As(III) and total As concentrations were of the same order of magnitude in the samples cured for 28 days as for 2 yr. However, consistently lower concentrations were detected in samples with longer cure time. The results of this study improve our understanding of arsenic speciation and leachability in the cement matrix after long cure times.

Original languageEnglish
Pages (from-to)1241-1247
Number of pages7
JournalChemosphere
Volume59
Issue number9
DOIs
StatePublished - Jun 2005

Keywords

  • Arsenic immobilization
  • Leachability
  • Speciation
  • XANES

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