低温选择性催化还原(SCR)脱硝是工业烟气末端治理的重要技术, 强化催化剂硫抗性是低温SCR领域内亟待解决的问题。本研究以羟基磷灰石(HAP)为载体、Mn为活性组分通过共沉淀法成功合成了Mn-HAP低温(100~200℃)脱硝催化剂, 探究了其脱硝性能及金属硫酸盐和硫酸铵的中毒特性。结果表明: 以HAP作为活性组分Mn的载体能一定程度上提高催化剂的抗硫性。当反应温度为140 ℃时, SCR催化剂脱硝效率达到100%, 金属硫酸盐相较硫酸铵对催化剂低温脱硝活性的影响更显著, 120 ℃时脱硝效率分别降低37.40%和8.83%。不同手段分析表明, 不同表面硫物种均会不同程度地降低催化剂比表面积并改变活性Mn氧化态。金属硫酸盐显著降低Mn⁴⁺/Mn比例是造成催化剂失活的主要原因。

Low-temperature selective catalytic reduction (SCR) denitrification is an important technology for the end treatment of flue gas and enhancing sulfur resistance of catalysts is a challenge demanding prompt solution in the field of low-temperature SCR. Here, a Mn-HAP catalyst for nitrogen removal at low temperature (100-200 ℃) was successfully synthesized by co-precipitation method using hydroxyapatite (HAP) as carrier and Mn as an active component, and then its denitrification performance and resistance to fight against metal sulfate and ammonium sulfate poisoning were studied. The results showed that the sulfur resistance of the catalyst could be improved to a certain extent by using HAP as Mn active substance carrier. When the reaction temperature was 140 ℃, the denitrification efficiency of the SCR catalyst reached 100%. Meanwhile, the effect of metal sulfate on the denitrification activity at low temperature was more significant than that of ammonium sulfate, and the denitrification efficiency under the two sulfate species at 120 ℃ was reduced by 37.40% and 8.83%, respectively, as compared with that of fresh catalyst. Different characterization analysis indicated that different surface sulfur species could reduce the specific surface area and change the oxidation state of active Mn to various degrees. The main reason for catalysts deactivation is that the metal sulfate can significantly decrease the proportion and oxidation-reduction performance of Mn⁴⁺. Therefore, this study provides an important direction for improving the sulfur resistance of SCR catalysts.