Determination of Thiocyanate in Desulfurization Waste Solution by Spectrophotometry

Affects of thiosulfate (S2O32-) and sulfate (SO42-) on determination of thiocyanate (SCN-) in desulfurization waste solution (DWS) by spectrophotometry were investigated. The experiment results suggested that S2O32- and Fe3+ generated purple compound [Fe(S2O3)2]- which has a strong absorption at 450nm, but the purple soon fades in this process. As long as the reacting time is longer than 120s, the impact of S2O32- can be eliminated. In addition, sulfate has no effect. At 450nm wavelength, linear relationship between concentration of SCN- and absorbance was C=19.7272A-0.2774, which conformed to the Beer Law in the range of 2.00 ~ 19.45μg•ml-1, the correlation coefficients was 0.9996. The Fe3+-SCN- spectrophotometric method of monitoring SCN- in desulfurization waste solution was feasible.