Establishment of separation method for polysulfide ions in wet desulfurization
Polysulfide ion Sx2- is an intermediate product of the conversion of H2S to elemental sulfur in wet catalytic oxidation desulfurization technology.In the desulfurization environment,there is a parallel competition between the sulfur evolution reaction and parasite reaction,and the existing form and concentration of Sx2- are the prerequisite for evaluating the degree of the two competitive reactions.In this paper,UV-vis,LC-MS,and HPLC methods were used to determine the existence and concentration of Sx2-.The results showed that the total concentration of Sx2- could be determined by the UV-vis method.The methylation method could capture each form of Sx2-,LC-MS and HPLC methods could separate each form of methylated polysulfide,and the larger the number of sulfur atoms(2-10)of Sx2-,the longer the retention time.Combined with the standard curve established by UV-vis and the relative intensity of each form of Sx2- on HPLC,the absolute concentration of each form of S2-in solution was calculated.S42-,S52-,S62- and S102- were the main types of sodium polysulfide solution,in which the concentration and pH had little effect on Sx2-,and the high temperature was not conducive to the formation of Sx2-,thus not conducive to the formation of elemental sulfur.This work laid a foundation for further research on the origin of parasites and the acceleration of sulfur evolution.