Identification and reactions of cyanide and thiocyanate in coal gasification wastewaters. Sixth quarterly report
This report discusses: (i) procedures for preservation and identification of cyanide and thiocyanate in coal gasification wastewaters, (ii) possible pathways for aqueous phase formation of thiocyanate in these waste-waters, and (iii) reaction of cyanide and polysulfide-sulfur to produce thiocyanate....
| Main Authors: | , , , |
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| Language: | unknown |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://www.osti.gov/servlets/purl/6532290 https://www.osti.gov/biblio/6532290 https://doi.org/10.2172/6532290 |
| Summary: | This report discusses: (i) procedures for preservation and identification of cyanide and thiocyanate in coal gasification wastewaters, (ii) possible pathways for aqueous phase formation of thiocyanate in these waste-waters, and (iii) reaction of cyanide and polysulfide-sulfur to produce thiocyanate. Cyanide preservation procedures require the removal of sulfide and high levels of carbonate. An analytical procedure for thiocyanate determination based on a copper-pyridine colorimetric method with pre-extraction has been tested successfully on most samples. Kinetic studies on the reaction of cyanide with polysulfide-sulfur showed that the reaction was of order 1.54 +- 0.25 with a rate constant of about 0.24 (M/l) /sup -0/ /sup 54//min. Results of this work may help predict interrelationships among cyanide, sulfur and thiocyanate during oxidation of coal gasification wastewaters. Control of cyanide-polysulfide reaction requires selective control of sulfide oxidation kinetics. |
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