State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology
College of Environmental Science and Engineering, Taiyuan University of Technology

煤炭清洁转化与高效利用是国家的战略需求，而煤气精脱硫净化是煤炭高效清洁利用中的关键环节。氧化锌是工业上普遍使用的中温脱硫剂，常用于精脱硫的最后一道工序，其在常低温条件下更有热力学优势，可实现超精脱硫，但受动力学制约，活性很低。同时，无论中温还是常低温氧化锌脱硫剂的再生性能均很不理想。目前工业上鲜有可再生循环使用的氧化锌脱硫剂，因此产生的固废使其面临巨大的环境压力。采用溶胶凝胶法制备了Co掺杂ZnO/SiO2复合脱硫剂，探究了Co掺杂量对ZnO/SiO2复合脱硫剂脱硫以及再生性能的影响。研究结果表明，Co物种是以Co2+的形式掺杂进入ZnO，适量掺杂Co可增大脱硫剂的比表面积，使ZnO表面晶格缺陷增加，进而提高脱硫剂表面碱性，促进H2S的解离，从而促进脱硫性能的提高；当掺杂量为3%时，穿透硫容为143 mg/g，是未掺杂ZnO脱硫剂的1.6倍。从程序升温氧化结果看，Co掺杂可以降低ZnO脱硫剂的再生温度，同时还可降低再生过程金属硫酸盐的生成量。尽管Co掺杂可在一定程度上降低ZnO脱硫剂的再生温度和抑制高温再生过程中生成硫酸盐，但并不能避免硫酸盐的生成。再生形成的硫酸盐会降低脱硫剂表面碱性，也会使脱硫剂的比表面积急剧下降，使得再生后脱硫剂的工作硫容明显降低。获得可循环利用的常温氧化锌脱硫剂仍存在较大的挑战。

Coal is the main source of energy, but it is also the main source of pollution. The clean transformation and efficient utilization of coal is a national strategic demand, and the desulfurization and purification of coal gas essence is the key link in the efficient and clean utilization of coal. ZnO is widely used in industry as a medium temperature desulfurizer, which is often used for fine desulfurization. It has more thermodynamic advantages at low temperature and can achieve superfine desulfurization, but its activity is very low due to the restriction of kinetics. At the same time, the regeneration performance of zinc oxide desulfurizer is not ideal either for medium temperature or normal low temperature. So far, there is no renewable and recycled desulfurizer of zinc oxide in industry, so the solid waste generated makes it face great environmental pressure. Based on this background, the influence of metal Co doping on the desulfurization and regeneration performance of zinc oxide at room temperature was investigated. Series of Co doped ZnO/SiO2 composites with different doping contents were prepared by a sol-gel method, and the effect of Co doping on the desulfurization and regeneration performance of ZnO/SiO2 adsorbents was studied in detail. The results indicated that Co is doped into ZnO in the form of Co2+, Co doping not only results in an increase of the specific surface area of adsorbents, but also increases the concentrations of lattice defects on the ZnO surface. The latter promotes the dissociation of H2S owing to its improvement on surface basicity. Both of the mentioned above are responsible for the enhanced performance. And the breakthrough sulfur capacity reaches the highest of 143 mg/g when the doping amount is 3%, 1.6 times than that of ZnO/SiO2 adsorbent. It is also found that although Co doping, to some extent, inhibits the formation of sulfate during the regeneration of ZnO adsorbents, their generation cannot be fully avoided. The sulfate will reduce the surface alkalinity of desulfurizer, and lead to a sharp decrease in the specific surface area of desulfurizer, so that the working sulfur capacity of desulfurizer after regeneration decreases significantly. It is still a great challenge to obtain a recyclable desulfurizer of zinc oxide at room temperature.

国家自然科学基金资助项目(22078223)；山西省青年基金资助项目(20210302123065)

苏哲林，李敏麒，杨超，等. Co掺杂ZnO/SiO2复合脱硫剂常温脱硫性能及再生性能[J]. 煤炭学报，2023，48(10)：3928−3936.

SU Zhelin，LI Minqi，YANG Chao，et al. Desulfurization and regeneration performance of Co doped ZnO/SiO2 composite desulfurizer at room temperature[J]. Journal of China Coal Society，2023，48(10)：3928−3936.