纳米硫化铜烟气脱汞及其机理研究

An Experimental and Mechanistic Study on the Elemental Mercury Removal Over Nano-sized Copper Sulfide

本研究采用沉淀法制备纳米硫化铜(nano-CuS),并评价了其汞吸附性能。nano-CuS最佳脱汞反应温度为75℃,适用于在FGD和WESP区间内喷射脱汞,避免高浓度酸性气体(SO2、NO)对脱汞性能的干扰.在N2,N2+4%O2、以及模拟烟气条件下,nano-CuS的吸附容量和吸附速率达到89.43~122.40 mg·g^-1及11.93~13.56μg·g^-1·min^-1,与文献报道的金属硫化物吸附剂相比至少高一个量级。通过汞程序升温脱附实验和系统的表征发现,nano-CuS中的硫以多态的形式存在,特别是多硫的含量明显高于文献报道的金属硫化物吸附剂。除此之外,由于铜与汞之间的强相互作用,铜活性位点同样参与到了气态汞的吸附当中,从而使得nano-CuS具有非常优异的汞吸附能力。该研究不仅可以为多硫汞吸附剂的简单化制备提供思路,还提供了一种有潜力的非炭基汞吸附剂。

In this study,nano-sized copper sulfide(nano-CuS) prepared by precipitation method was evaluated for its elemental mercury(Hg0) removal performance.The optimal operation temperature for Hg0 capture over nano-CuS was 75℃,which highly matches with the temperature range between the FGD and WESP systems.This warrants the sorbent free of the detrimental effect exerted by high-concentration acidic gas,e.g.,SO2 and NO.The adsorption capacity and rate reached 89.43~122.40 mg·g^-1 and 11.93~13.56 μg·g^-1·min^-1 under N2,N2+4%O2 and simulated flue gas,respectively,at least one magnitude higher than previously reported mineral sulfide based sorbents.Further mercury temperature programmed desorption and characterizations proved that multiform of sulfur species co-exist in nano-CuS.Especially the polysulfide content is significantly higher than previously reported mineral sulfide based sorbents.Besides,due to the strong interaction between the mercury and copper,the copper-terminated sites in nano-CuS was active for Hg0 capture.These induced the superior Hg0 removal performance of the as-synthesized nano-CuS.This study not only gives a new mindset for simplyfing the design of polysulfide contained sorbents,but also provides a potential noncarbonaceous materials for Hg0 decomtamination.