Abstract: In order to restrain the anode passivation and increase the conversion ratio and current efficiency of sulfide to sulfur during the electrolysis of H₂S-loaded sodium carbonate solution, direct electrolysis method by a filter press electrolyzer was used to recycle sulfur and hydrogen. Graphite was used as anode,and H₂S-loaded sodium carbonate solution as anolytes;Titanium mesh was used as cathode and sodium hydroxide solution as catholytes. The effects of some parameters on anodic reactions were investigated,such as temperature,pH,initial concentration and current density. Results indicated that the conversion ratio of sulfide increased with the increase of initial sulfide concentration,but decreased with the increase of current density. Moreover,the appropriate electrolytic conditions were at temperature of 75℃,initial sulfide concentration above 0.5mol/L,current density of 10-20mA/cm²,and no sodium hydroxide addition into anolytes. Under the above conditions,the conversion ratio of sulfide could exceed 85%. The characterization of recovered sulfur with XRD and SEM methods showed that the produced sulfur was rhombi with bigger particle diameter,which was favorable in solid-liquid separation.

Key words: electrolysis, hydrogen sulfide, absorption, oxidation, sulfide

摘要： 在电解碳酸钠吸收硫化氢的富液过程中,为了降低阳极钝化,提高负二价硫向零价硫的转化率和电流效率,采用板框式电解槽直接电解法回收硫黄和氢气,其中石墨电极为阳极,碳酸钠溶液吸收硫化氢富液为阳极液,钛网电极为阴极,氢氧化钠溶液为阴极液。实验考察了温度、pH值、初始溶液浓度、电流密度等因素对电解过程阳极反应的影响。结果表明:溶液中S^2-的转化率随温度和初始溶液中Na₂S浓度的增大而增大,而随电流密度的增大而降低。确定了适宜的电解条件为电解温度75℃,初始硫化钠溶液浓度在0.5mol/L以上,电流密度10~20mA/cm²,且初始阳极液中不加氢氧化钠为佳,此时阳极液中S^2-的转化率可达85%以上。对回收硫黄的XRD、SEM表征结果表明,所生成的硫黄以斜方硫的形式存在,且硫黄颗粒粒径变大,有利于固液分离。

关键词: 电解, 硫化氢, 吸收, 氧化, 硫化物