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湿法脱硫系统对燃煤电站烟气中的Hg2+具有良好的脱除作用,但Hg2+在脱硫系统内会被还原变为Hg0再次释放,造成汞的二次污染.本文系统研究了不同pH值条件下,温度、SO32-浓度以及O2浓度对Hg2+的还原再释放的影响.实验结果表明:相同pH值条件下,温度的升高会极大地促进Hg2+的还原释放,溶液中SO32-离子浓度的增大会与Hg2+反应生成Hg(SO3)2-从而抑制了Hg2+的还原;pH降低会造成配合物HgSO3的质子化,促进Hg0的再释放.O2的存在会破坏Hg(SO3)22-的稳定性,并且O2浓度越高这种破坏作用越明显,从而增强Hg2+的还原再释放.同时,在较高pH值环境下,溶液中SO42-含量较高进而抑制Hg2+的释放.“,”The wet flue gas desulphurization (WFGD) system could effectively remove Hg2+ from coal combustion flue gas.However,the Hg2+ couldbe reduced in WFGD system,resulting in Hg0 re-emission.In this work,the interaction between Hg2+ and SO32-in aqueous phase was studied by means of controlling the pH value.The operating temperature,the concentration of SO32-and O2 were investigated.The experiment results indicated that the Hg2+ reduction was promoted with the increase of operating temperature,while the increase of SO32-concentration would inhibit Hg2+ reduction by forming the complex Hg(SO3)22-.Lower pH value enhanced the re-emission of Hg0 for the reason that complex HgSO3 was apt to decompose due to its protonation.The presence of O2 would break the stabilization of Hg(SO3)22-resulting in Hg2+ re-emission.In the meanwhile,more SO42-contributed by higher pH value,which would help the inhibition of Hg2+ emission.