The effect of silica fume on biodegradation of cement paste and its capacity to immobilize strontium during exposure to microbial sulfur oxidation

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The disposal of low-level radioactive waste containing isotopes such as strontium by immobilization in cement paste has become common practice. However, the stability of cement paste in the environment may be impaired by sulfuric acid produced by sulfur-oxidizing bacteria. Since biodegradation rates in the environment of most radioactive waste burial sites are too low to be measured, determination of the degradation kinetics of cement paste is a difficult task. This study reports on the development of an accelerated biodegradation system for cement pastes in which the cement paste is exposed to a continuous culture of the sulfur-oxidizing bacterium Halothiobacillus neapolitanus. This system facilitated detection of the biodegradation processes in cement paste after as short a time as 15 days. A comparison of the durability of a cement paste blended with silica fume with that of unblended cement paste showed that the silica fume induced an increase in the leaching of Ca+2 and Si and enhanced weight loss, indicating rapid deterioration in the structural integrity of the cement paste. The leaching of Sr+2 from the silica fume amended cement paste was slightly reduced as compared with the non amended cement paste, indicating an increase in immobilization of strontium. Nevertheless, our findings do not support the use of silica fume as a suitable additive for immobilization of low-level radioactive waste.

Original languageEnglish
Pages (from-to)321-328
Number of pages8
JournalBiodegradation
Volume19
Issue number3
DOIs
StatePublished - 1 Jun 2008

Keywords

  • Biodegradation
  • Cement paste
  • Radioactive waste
  • Silica fume
  • Sulfur-oxidizing bacteria

ASJC Scopus subject areas

  • Environmental Engineering
  • Microbiology
  • Bioengineering
  • Environmental Chemistry
  • Pollution

Fingerprint

Dive into the research topics of 'The effect of silica fume on biodegradation of cement paste and its capacity to immobilize strontium during exposure to microbial sulfur oxidation'. Together they form a unique fingerprint.

Cite this