A strategy of KIT-6-carrier modification towards enhancement of desulfurization properties of mesoporous Zn-based sorbents for H2S removal from hot coal gas

Modification of KIT-6 by Ti/W doping (with one-pot synthesis method) was proposed for improving desulfur-ization performance of ZnO-KIT-6 sorbent. The characterization results indicate that the dopant atoms are present in the form of Ti4+ and W6+, the ordered mesoporous structure of KIT-6 can be retained at Me/Si doping ratios of 1/50-1/20. The presence of [TiO4]4- units in Ti-doped carriers demonstrates that a part of Ti atoms incorporates into the silica framework. Furthermore, moderate Ti doping causes more porous KIT-6 but W doping results in the decline in the specific surface area. Metal doping of Ti/W both show the effects of pore expansion as well as improvement of ZnO-dispersion, favorable for the sulfidation reaction. Generally, the desulfurization properties of sorbents are greatly enhanced by carrier modification. The highest breakthrough sulfur capacity of sorbents containing Ti or W doped KIT-6 are approximate (7.07 and 7.14 g S/100 g sorbent for Ti and W doping, respectively). However, W modification results in greater decrease in orderness of carriers. Additionally, sorbent with Ti-doped carriers has more stable H2S-uptake capacity during five successive sulfidation/regeneration cy-cles, showing great potential for industrial applications.