Synthesis, characterization and evaluation of porous polybenzimidazole materials for CO2 adsorption at high pressures

Abstract

Porous polybenzimidazole polymers have been under investigation for high and low pressure CO 2 adsorption due to the well-built stability under high pressure and at various temperatures. Pressure swing and temperature swing processes like integrated gasification combined cycle require materials which can operate efficiently at high pressure and high temperature and can remove CO 2 . In this manuscript we report synthesis, characterization and evaluation of two polybenzimidazole materials (PBI-1 and PBI-2), which were prepared with two different solvents and different cross-linking agents by condensation techniques. Low and high pressure CO 2 sorption characteristic of both the materials were evaluated at 273 and 298 K. Thermal gravimetric analysis showed high temperature stability up to 500°C for the studied materials. PBI-1 has shown very good performance by adsorbing 3 times more (1.8025 mmolg -1 of CO 2 ) than PBI-2 at 0°C and at low pressures. Despite low surface area results obtained via BET techniques, at 50 bars PBI-1 adsorbed up to 6.08 mmolg -1 of CO 2 . Studied materials have shown flexible behavior under applied pressure that leads to so-called ''gate-opening'' adsorption behavior and it makes these materials promising adsorbents of CO 2 at high pressures and it is discussed in the manuscript in detail.

Molecular Insights into Benzimidazole‐Linked Polymer Interactions with Carbon Dioxide and Nitrogen

“…The experimental data were previously published by our group and the details of the experimental procedure, uncertainties and reproducibility can be found elsewhere . Experimental values are re‐plotted and given in Figure S3.…”

“…Structures . Two MBI structures, namely MBI1 and MBI2 were considered based on previous work (Figure ) and the details of the synthesis of the MBI structures are given in the ESI. Molecular clusters containing MBI1+CO 2 , MBI1+N 2 MBI1+2CO 2 , MBI2+CO 2 , MBI2+N 2 , MBI2+2CO 2 were studied by considering different CO 2 and N 2 spatial positions based on the to infer interaction properties at all logical active sites of the MBI molecules (e. g. p1, p2, p3 positions for CO 2 and N 2 ).…”

“…In this work, two benzimidazole‐linked polymer monomers (MBI) were studied in detail for their gas sorption performances at various sorption sites via density functional theory (DFT) approach. Obtained interaction energies and topology of the electron density obtained via atom in a molecule approach were compared to experimental findings that were recently published for the same materials in order to highlight the gas sorption stabilization by MBI structure through Lewis acid–base (N⋅⋅⋅CO2) and aryl C–H⋅⋅⋅O=C=O interactions . Details of the methods and the findings are given below.…”

Preparation and Characterization of Polyamides and Nitrogen‐doped Carbons for Enhanced CO2 Capture

“…For this purpose, certain materials with a high porosity have been deemed sorbents for CO 2 capture and storage (CCS) due to enhanced contact area between gas molecules and adsorbents. Various porous materials (exclusively solid adsorbents) including metal organic frameworks (MOFs), zeolites, activated carbon, mesoporous silica, and many organic polymers have been explored as adsorbents. Among these solid sorbents, organic polymers exhibit additional benefits including facile and economical preparation, abundant availability, biodegradability, non‐toxicity, and structural flexibility for capturing gases under variable environmental conditions .…”

Solid Sorbents as a Retrofit Technology for CO2 Removal from Natural Gas Under High Pressure and Temperature Conditions

“…The sudden increase in the NbOFFI-1-Ni adsorption between 5-7 bar pressures (Fig. 7a,c) may be explained, in part, by what is referred to as gate opening adsorption 38 . The phenomena is related to the expansion of the cage structure with the presence of enough adsorbed gas up to a certain pressure where the pressure does not allow any further expansion.…”