Valuing Metal–Organic Frameworks for Postcombustion Carbon Capture: A Benchmark Study for Evaluating Physical Adsorbents

Abstract

The development of practical solutions for the energy-efficient capture of carbon dioxide is of prime importance and continues to attract intensive research interest. Conceivably, the implementation of adsorption-based processes using different cycling modes, e.g., pressure-swing adsorption or temperature-swing adsorption, offers great prospects to address this challenge. Practically, the successful deployment of practical adsorption-based technologies depends on the development of made-to-order adsorbents expressing mutually two compulsory requisites: i) high selectivity/affinity for CO and ii) excellent chemical stability in the presence of impurities. This study presents a new comprehensive experimental protocol apposite for assessing the prospects of a given physical adsorbent for carbon capture under flue gas stream conditions. The protocol permits: i) the baseline performance of commercial adsorbents such as zeolite 13X, activated carbon versus liquid amine scrubbing to be ascertained, and ii) a standardized evaluation of the best reported metal-organic framework (MOF) materials for carbon dioxide capture from flue gas to be undertaken. This extensive study corroborates the exceptional CO capture performance of the recently isolated second-generation fluorinated MOF material, NbOFFIVE-1-Ni, concomitant with an impressive chemical stability and a low energy for regeneration. Essentially, the NbOFFIVE-1-Ni adsorbent presents the best compromise by satisfying all the required metrics for efficient CO scrubbing.

An Ultrastable Metal Azolate Framework with Binding Pockets for Optimal Carbon Dioxide Capture

“…Second, later on, af amily of pillared-square-grid metal-organic materials, namely SIFSIX-n and analogues,w ere developed by taking advantage of pore size selectivity in gas separation. [12][13][14][15] In the cases of SIFSIX-3-Cu [13] and Qc-5-Cu-sql-b, [15] the pore sizes were judiciously engineered to achieve ultrahigh selectivity and also lower the energy costs for regeneration, but ac ompromise in uptake capacity is inevitable.F urthermore, the related NbOFFIVE-1-Ni was demonstrated to be stable toward moisture and highly efficient for CO 2 capture under fuel gas stream [7] and direct air capture conditions. [14] At hird, sporadic type of MOF adsorbents also exhibited excellent ability for carbon dioxide capture,which was mainly attributed to their collective binding sites,a sexemplified by Zn 2 (Atz) 2 (ox), [16] NOTT-300, [17] UTSA-16, [18] and MAF-23.…”

“…[1,2] Essentially,i ti st he ease of design down to their molecular building blocks and underlying topologies for this new class of crystalline porous materials that guarantees ab road spectrum of applications, [3][4][5] especially for addressing utilitarian concerns such as storage for alternative fuels and separation for clean air (for example carbon dioxide capture). [6,7] To satisfy the urge of achieving both high uptake capacity/selectivity and low energy penalty,significant advances are made concerning the development of two important types of MOF adsorbents in the recent decade. [8][9][10][11][12][13][14][15] First, the success of MOF-74 (CPO-27) and related materials brought forward the role of open metal sites in efficient carbon capture.…”

“…[43] Themaintained crystallinity,indicated by unaltered PXRD patterns (Figure 2b), after immersing the bulk samples in boiling water (9 days), acidic/basic solutions or various organic solvents also suggested Zn(imPim) might be suitable for capturing CO 2 from flue gas,a ni ndustrial environment typically under high temperature and containing moisture and acid gases. [6,7] In the adsorption experiments (Supporting Information, Figure S9), Zn(imPim) showed at ypical type-I isotherm for CO 2 at room temperature,exhibiting asteep uptake increase below 150 mbar.T his is similar to the situation for afew MOFs with collective binding sites,for example,Z n 2 (Atz) 2 (ox), [16] NOTT-300 [17] and UTSA-16, [18] which prompted us to study the direct observation of CO 2 loaded in Zn-(imPim). As imple apparatus was set up to demonstrate the carbon dioxide capture can be achieved at ambient environment (Figure 3a).…”

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

“…CO 2 capture from post combustion can be used in both new and existing CO 2 emitting industries and power plants and hence has been the focus of many research and technological advancements. Such technologies can be categorized as chemical or physical in nature and are based on adsorption, cryogenic processes and membrane separations 6,7 . Amine scrubbing is one of the most advanced benchmark CO 2 adsorption process that employs different types of amines 8 .…”

“…In addition, controlling the pore sizing and the functionalization of the adsorbent have been reported as two of the most prominent factors affecting gas separation and uptake 16 . Since post combustion requires the separation to occur at higher pressures and elevated temperature, it is essential to find solid adsorbents that can capture the CO 2 under such extreme circumstances under many cycles of operation 7,17 .…”