Zhou Jian, Zhang Ni, Meng Tao, Guo Qiangsheng, Xue Zhaoteng, Mao Dongsen
School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, China.
Nanomaterials (Basel). 2024 Sep 26;14(19):1558. doi: 10.3390/nano14191558.
Fluoride treatment of ZSM-5 zeolite can effectively adjust surface acidity and generate a secondary pore structure. In this study, a series of modified nano-HZSM-5 zeolites were prepared by NHF-HF mixed solution treatment and applied to the selective conversion of bioethanol to propylene at 500 °C, atmospheric pressure, and a WHSV of 10 h. The results showed that NHF-HF modification weakened the surface acidity of nano-HZSM-5 zeolites, thus inhibiting coke formation. Additionally, the mesopores in the nano-HZSM-5 zeolites increased after NHF-HF treatment, thereby enhancing the mass transfer rate and improving the coke-resistance ability. The NHF-HF mixed solution modification significantly improved the stability of nano-HZSM-5 zeolites in catalyzing bioethanol to propylene and greatly extended the working life of nano-HZSM-5 zeolites. It can be seen from the characterization of the deactivated catalysts that coke deposition and weakening of acidity may be the key factors for catalyst deactivation.
对ZSM-5沸石进行氟化物处理可有效调节其表面酸性并生成二次孔结构。在本研究中，通过NHF-HF混合溶液处理制备了一系列改性纳米HZSM-5沸石，并将其应用于在500℃、常压和10 h的质量空速条件下将生物乙醇选择性转化为丙烯。结果表明，NHF-HF改性减弱了纳米HZSM-5沸石的表面酸性，从而抑制了焦炭的形成。此外，NHF-HF处理后纳米HZSM-5沸石中的介孔增加，从而提高了传质速率并增强了抗焦能力。NHF-HF混合溶液改性显著提高了纳米HZSM-5沸石催化生物乙醇制丙烯的稳定性，并大大延长了纳米HZSM-5沸石的使用寿命。从失活催化剂的表征可以看出，焦炭沉积和酸性减弱可能是催化剂失活的关键因素。
