The rate of the reversible homogeneous disproportionation of polysulfides was studied by following the optical absorbance of polysulfide solutions in a continuous plug flow reactor equipped with an on-line photometric detector. In order to avoid heterogeneous slow reactions involving sulfur colloids or precipitate, the reaction was initiated by an abrupt pH change from an undersaturated solution containing predominantly tetrasulfide species to a pH where pentasulfide is the dominant species. The disproportionation was found to follow first order reversible reaction dynamics. At environmentally relevant conditions the characteristic time of the disproportionation reaction is of the order of 10 s. This characteristic time implies that necessary conditions for speciation of the different polysulfide species by chromatography or another separation and subsequent quantification scheme should be of the order of 1 s.
|Original language||American English|
|Number of pages||14|
|State||Published - 2003|
Bibliographical noteFunding Information:
We gratefully acknowledge the financial support of the Ministry of Environmental Quality, Israel.
- Activation energy
- Disproportionation kinetics
- Inorganic polysulfides
- Reduced sulfur compounds