Mixed-matrix membranes containing zero-dimension porphyrin-based complex for propylene/propane separation

• Published in: Separation and purification technology 2023-06, Vol.314, p.123656, Article 123656
• Main Authors: Peng, Donglai, Duan, Shaofan, Feng, Xiaoquan, Liu, Zongkai, Wang, Jing, Li, Dongyang, Zhang, Yatao
• Format: Article
• Language: English
• Subjects: Mixed-matrix membrane; Non-porous fillers; Porphyrin-based complex; Propylene/propane separation
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2023.123656

[Display omitted] •It is the first time to use zero-dimension porphyrin-based complex as filler in membrane for C3H6/C3H8 separation.•The porphyrin-based complex possesses abundant metal sites that can facilitated C3H6 transport through membrane.•The porphyrin-based complex possesses can be dissolved in organic solvent under low concentration that can conduce to uniform dispersion in MMMs.•The resultant MMMs based on zero-dimension porphyrin-based complex exhibit excellent C3H6/C3H8 separation performance. The membrane-based technology for propylene/propane (C3H6/C3H8) separation is very promising due to its low-energy separation process with high effectiveness. Herein, we propose a new type of mixed-matrix membranes (MMMs) containing zero-dimension non-porous porphyrin-based complex (M-TMCPP, M = Zn2+, Cd2+, Ni2+) with coordinatively unsaturated metal sites. Density functional theory calculation results show that M-TMCPP can form π complexation with C3H6 and facilitate C3H6 molecule through membranes. Different from porous nanofillers, M-TMCPP exhibits zero-dimension non-porous molecular structure and can be dissolved in solvent at molecular lever under low concentration. Benefiting from the favorable interaction between C3H6 with metal sites and the uniform distribution of M-TMCPP particles and/or even independent M-TMCPP molecules in polymer, the porphyrin-based complexes are used as nanofillers in fluorinated polyimide (6FDA-DAM). The prepared MMMs exhibit an extraordinary C3H6/C3H8 ideal selectivity of up to 45.6 with a high C3H6 permeability of 70.3 Barrer, far surpassing the previously reported 6FDA-based polyimide MMMs and polymeric membranes. Membrane performances of three different M-TMCPP MMM were studied and the gas transportation mechanism was evaluated. This work provides a new conceptual approach of using non-porous zero-dimensional complexes with coordinatively unsaturated sites as fillers in mixed matrix membranes, which not only can accomplish olefin/alkane separation with ultrahigh performance, but also indicates its high potential for feasible usage.