A metal-OH group modification strategy to prepare highly-hydrophobic MIL-53-Al for efficient acetone capture under humid conditions

• 作者: Jiaqi Shi Rui Han Shuangchun Lu Qingling Liu
• 来源期刊: 环境科学学报（英文版）
• 年，卷（期）: 2021,（9）
• 所属期刊栏目: Regular articles
• 页码范围: 111-123
• 页数: 13页
• 语种: 英文

摘要

A series of highly-hydrophobic MIL-53-Al (MIL= Materials of Institut Lavoisier) frameworks synthesized via decoration of the Al-OH groups by alkyl phosphonic acid were developed as adsorbents for removing acetone from humid gas streams. The newly prepared materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), N2 adsorption-desorption and thermogravimetric analysis (TGA). Their adsorption behaviors toward acetone vapor under dry and wet condi-tions were studied subsequently. Results showed that alkyl phosphonic acid was success-fully grafted into MIL-53-Al skeleton through coordinating interaction with Al3+ generating MIL-53-Al@Cx (x= 12, 14, 18). The MIL-53-Al@Cx exhibited similar crystal structure and ther-mal stability to parent MIL-53-Al. Furthermore, the modified materials showed significantly enhanced hydrophobicity. The water vapor uptake of MIL-53-Al@C14 decreased by 72.55％ at 75％ relative humidity (RH). Dynamic adsorption experiments demonstrated that wa-ter vapor had almost no effect on the acetone adsorption performance of MIL-53-Al@C14. Under the condition of 90％ RH, the acetone adsorption capacity of MIL-53-Al@C14 was 102.98％ higher than that of MIL-53-Al. Notably, MIL-53-Al@C14 presented excellent adsorp-tion reversibility and regeneration performance in 10 adsorption-desorption cycles. Taken together, the strategy of metal-OH group modification is an attractive way to improve the acetone adsorption performance over metal-organic frameworks (MOFs) under humid con-ditions. Besides, MIL-53-Al@C14 would be deemed as a promising candidate for capturing acetone in high moisture environment.