Thiol–Amino Bifunctional Metal–Organic-Framework-Based Membrane Regulating Hydrophobic Sites for Selective Separation of Artesunate

• Published in: Inorganic chemistry 2024-08, Vol.63 (31), p.14699-14711
• Main Authors: Zhang, Chuanxun, Hu, Bo, Ren, Jiajia, Du, Wanqi, Meng, Minjia
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X; 1520-510X
• DOI: 10.1021/acs.inorgchem.4c02295

The selective separation and purification of artesunate (ARU) and artemisinin (ART) using zirconium-based metal–organic frameworks (MOF), especially UiO-66 MOF, are receiving increasing attention. In this study, tunable “hydrophobic” sites of thiol (–SH) were introduced to amino-functionalized MOFs (UiO-66-NH2) to fabricate a thiol-amino bifunctional UiO-66/polyvinylidene fluoride (PVDF)-blended membrane (S1-UiO/PVDF-DPIM) via the delayed-phase-inversion method for selective separation of ARU/ART. The adsorption results indicated that the modification of UiO-66-NH2 with thiol can indeed increase the ARU adsorption. The thiol-functional MOF (S1-UiO-66-NH2) was chosen as the optimal thiol-amino bifunctional MOF, as it possessed the maximum ARU adsorption capacity (111.14 mg g–1) and the highest selective-separation factor (α = 51.84). The ATR FT-IR dynamic spectrum disclosed the recognition mechanism, indicating that incorporating thiol groups into a hydrophilic MOF as hydrophobic sites can boost adsorption efficiency. Moreover, the static-selective permeation results showed that the S1-UiO/PVDF-DPIM preferentially transfers ARU when mixed with ART, even achieving complete ARU/ART separation. The most crucial aspect was the introduction of a hydrophobic core of –SH and new spontaneously formed disulfide bonds to S1-UiO/PVDF-DPIM, creating alternated hydrogen bonds and hydrophobic interactions. This work provides an alternative strategy to prepare hydrophobic–hydrophilic MOF-based membranes for the highly efficient and selective separation of complex analogue systems.