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Soto C, Torres-Cuevas ES, González-Ortega A, Palacio L, Prádanos P, Freeman BD, Lozano ÁE, Hernandez A. Hydrogen Recovery by Mixed Matrix Membranes Made from 6FCl-APAF HPA with Different Contents of a Porous Polymer Network and Their Thermal Rearrangement. Polymers (Basel) 2021; 13:4343. [PMID: 34960894 PMCID: PMC8703379 DOI: 10.3390/polym13244343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 01/16/2023] Open
Abstract
Mixed matrix membranes (MMMs) consisting of a blend of a hydroxypolyamide (HPA) matrix and variable loads of a porous polymer network (PPN) were thermally treated to induce the transformation of HPA to polybenzoxazole (β-TR-PBO). Here, the HPA matrix was a hydroxypolyamide having two hexafluoropropyilidene moieties, 6FCl-APAF, while the PPN was prepared by reacting triptycene (TRP) and trifluoroacetophenone (TFAP) in a superacid solution. The most probable size of the PPN particles was 75 nm with quite large distributions. The resulting membranes were analyzed by SEM and AFM. Up to 30% PPN loads, both SEM and AFM images confirmed quite planar surfaces, at low scale, with limited roughness. Membranes with high hydrogen permeability and good selectivity for the gas pairs H2/CH4 and H2/N2 were obtained. For H2/CO2, selectivity almost vanished after thermal rearrangement. In all cases, their hydrogen permeability increased with increasing loads of PPN until around 30% PPN with ulterior fairly abrupt decreasing of permeability for all gases studied. Thermal rearrangement of the MMMs resulted in higher permeabilities but lower selectivities. For all the membranes and gas pairs studied, the balance of permeability vs. selectivity surpassed the 1991 Robeson's upper bound, and approached or even exceeded the 2008 line, for MMMs having 30% PPN loads. In all cases, the HPA-MMMs before thermal rearrangement provided good selectivity versus permeability compromise, similar to their thermally rearranged counterparts but in the zone of high selectivity. For H2/CH4, H2/N2, these nonthermally rearranged MMMs approach the 2008 Robeson's upper bound while H2/CO2 gives selective transport favoring H2 on the 1991 Robeson's bound. Thus, attending to the energy cost of thermal rearrangement, it could be avoided in some cases especially when high selectivity is the target rather than high permeability.
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Affiliation(s)
- Cenit Soto
- Surfaces and Porous Materials (SMAP), Associated Research Unit to CSIC, Facultad de Ciencias, University of Valladolid, Paseo Belén 7, E-47011 Valladolid, Spain; (C.S.); (L.P.); (P.P.)
- Institute of Sustainable Processes (ISP), Dr. Mergelina s/n, E-47011 Valladolid, Spain
| | - Edwin S. Torres-Cuevas
- McKetta Department of Chemical Engineering, Texas Materials Institute, The University of Texas at Austin, 200 E Dean Keeton St., Austin, TX 78712, USA; (E.S.T.-C.); (B.D.F.)
| | - Alfonso González-Ortega
- Department of Organic Chemistry, School of Sciences, Facultad de Ciencias, University of Valladolid, Paseo Belén 7, E-47011 Valladolid, Spain;
| | - Laura Palacio
- Surfaces and Porous Materials (SMAP), Associated Research Unit to CSIC, Facultad de Ciencias, University of Valladolid, Paseo Belén 7, E-47011 Valladolid, Spain; (C.S.); (L.P.); (P.P.)
- Institute of Sustainable Processes (ISP), Dr. Mergelina s/n, E-47011 Valladolid, Spain
| | - Pedro Prádanos
- Surfaces and Porous Materials (SMAP), Associated Research Unit to CSIC, Facultad de Ciencias, University of Valladolid, Paseo Belén 7, E-47011 Valladolid, Spain; (C.S.); (L.P.); (P.P.)
- Institute of Sustainable Processes (ISP), Dr. Mergelina s/n, E-47011 Valladolid, Spain
| | - Benny D. Freeman
- McKetta Department of Chemical Engineering, Texas Materials Institute, The University of Texas at Austin, 200 E Dean Keeton St., Austin, TX 78712, USA; (E.S.T.-C.); (B.D.F.)
| | - Ángel E. Lozano
- Surfaces and Porous Materials (SMAP), Associated Research Unit to CSIC, Facultad de Ciencias, University of Valladolid, Paseo Belén 7, E-47011 Valladolid, Spain; (C.S.); (L.P.); (P.P.)
- Departament of Macromolecular Chemistry, Institute for Polymer Science and Technology (ICTP-CSIC), Juan de la Cierva 3, E-28006 Madrid, Spain
- IU CINQUIMA, University of Valladolid, Paseo Belén 5, E-47011 Valladolid, Spain
| | - Antonio Hernandez
- Surfaces and Porous Materials (SMAP), Associated Research Unit to CSIC, Facultad de Ciencias, University of Valladolid, Paseo Belén 7, E-47011 Valladolid, Spain; (C.S.); (L.P.); (P.P.)
- Institute of Sustainable Processes (ISP), Dr. Mergelina s/n, E-47011 Valladolid, Spain
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