Influence of calcium hydroxide on the fate of perfluorooctanesulfonate under thermal conditions

Fei Wang, Xingwen Lu, Kaimin Shih, Chengshuai Liu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

33 Citations (Scopus)

Abstract

To explore the potential fate and transport of perfluorochemicals in the thermal treatment of sludge, perfluorooctanesulfonate (PFOS), a perfluorochemical species commonly dominant in wastewater sludge, was mixed with hydrated lime (Ca(OH)2) to quantitatively observe their interaction under different temperatures. The phase compositions of the mixtures after the reactions were qualitatively identified and quantitatively determined using X-ray diffraction technique. The results of the thermogravimetry and differential scanning calorimetry analyses indicate that PFOS gasified directly during the thermal treatment process when the temperature was increased to around 425°C. However, the formation of CaF2 at 350°C suggests that the presence of Ca(OH)2 in the mixture can lead to the decomposition of PFOS at 350°C, which is lower than the decomposition temperature of PFOS alone (425°C). The increase of temperature promoted a solid state reaction between PFOS and Ca(OH)2, and also enhanced the interaction between the gaseous products of PFOS and CaO (or Ca(OH)2). The preferred Ca/F molar ratio to achieve fluorine stabilization by Ca(OH)2 was above 1:1 in the experiment involving 400°C and 600°C treatment. It also showed that equilibrium efficiency is achieved within 5min at 400°C and within 1min above 600°C.

Original languageEnglish
Pages (from-to)1067-1071
Number of pages5
JournalJournal of Hazardous Materials
Volume192
Issue number3
DOIs
Publication statusPublished - 15 Sept 2011

Keywords

  • PFOS
  • Transformation ratio
  • XRD quantification

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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