Abstract:

Polysulfide ion {\mathrm{S}}_x^{\mathrm{2}-} 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 {\mathrm{S}}_x^{\mathrm{2}-} 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 {\mathrm{S}}_x^{\mathrm{2}-}. The results showed that the total concentration of {\mathrm{S}}_x^{\mathrm{2}-} could be determined by the UV-vis method. The methylation method could capture each form of {\mathrm{S}}_x^{\mathrm{2}-}, LC-MS and HPLC methods could separate each form of methylated polysulfide, and the larger the number of sulfur atoms (2—10) of {\mathrm{S}}_x^{\mathrm{2}-}, the longer the retention time. Combined with the standard curve established by UV-vis and the relative intensity of each form of {\mathrm{S}}_x^{\mathrm{2}-} on HPLC, the absolute concentration of each form of {\mathrm{S}}_x^{\mathrm{2}-} in solution was calculated. {\mathrm{S}}_{\mathrm{4}}^{\mathrm{2}-}, {\mathrm{S}}_{\mathrm{5}}^{\mathrm{2}-}, {\mathrm{S}}_{\mathrm{6}}^{\mathrm{2}-} and {\mathrm{S}}_{\mathrm{10}}^{\mathrm{2}-} were the main types of sodium polysulfide solution, in which the concentration and pH had little effect on {\mathrm{S}}_x^{\mathrm{2}-}, and the high temperature was not conducive to the formation of {\mathrm{S}}_x^{\mathrm{2}-}, 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.

Key words: polysulfide ions, wet desulfurization, sodium sulfide

摘要：

多硫离子{\mathrm{S}}_x^{\mathrm{2}-}是湿式催化氧化脱硫技术中H₂S向单质硫转化的中间产物，在脱硫环境中，析硫反应和副盐反应存在平行竞争关系，{\mathrm{S}}_x^{\mathrm{2}-}的存在形态及浓度是评价两个竞争反应程度的前提条件。本文通过紫外-可见分光光度法（UV-vis）、液相色谱-质谱仪（LC-MS）和高效液相色谱（HPLC）方法可实现对{\mathrm{S}}_x^{\mathrm{2}-}的存在形态及各形态浓度定量测定的目标。结果表明：UV-vis法可测定出S _x^2-的总浓度；甲基化法可将{\mathrm{S}}_x^{\mathrm{2}-}的各个形态进行捕捉，LC-MS和HPLC法可将各形态的甲基化多硫化物分离，且{\mathrm{S}}_x^{\mathrm{2}-}的硫原子数（2—10）越大保留时间越长；结合UV-vis建立的标准曲线和HPLC上各个形态{\mathrm{S}}_x^{\mathrm{2}-}出峰的相对强度，推算出溶液中各形态{\mathrm{S}}_x^{\mathrm{2}-}的绝对浓度；多硫化钠溶液主要以{\mathrm{S}}_{\mathrm{4}}^{\mathrm{2}-}、{\mathrm{S}}_{\mathrm{5}}^{\mathrm{2}-}、{\mathrm{S}}_{\mathrm{6}}^{\mathrm{2}-}、{\mathrm{S}}_{\mathrm{10}}^{\mathrm{2}-}为主，其中浓度和pH对{\mathrm{S}}_x^{\mathrm{2}-}的影响较小，而温度过高不利于{\mathrm{S}}_x^{\mathrm{2}-}的生成，从而不利于单质硫的生成。这一项工作为进一步从源头上研究副盐成因及加快析硫反应的研究奠定了基础。

关键词: 多硫离子, 湿法脱硫, 硫化钠