Monolith-Supported Amine-Functionalized Mg₂(dobpdc) Adsorbents for CO₂ Capture

Abstract

The potential of using an amine-functionalized metal organic framework (MOF), mmen-M(dobpdc) (M = Mg and Mn), supported on a structured monolith contactor for CO capture from simulated flue gas is explored. The stability of the unsupported MOF powders under humid conditions is explored using nitrogen physisorption and X-ray diffraction analysis before and after exposure to humidity. Based on its superior stability to humidity, mmen-Mg(dobpdc) is selected for further growth on a honeycomb cordierite monolith that is wash-coated with α-alumina. A simple approach for the synthesis of an Mg(dobpdc) MOF film using MgO nanoparticles as the metal precursor is used. Rapid drying of MgO on the monolith surface followed by a hydrothermal treatment is demonstrated to allow for the synthesis of a MOF film with good crystallite density and favorable orientation of the MOF crystals. The CO adsorption behavior of the monolith-supported mmen-Mg(dobpdc) material is assessed using 10% CO in helium and 100% CO, demonstrating a CO uptake of 2.37 and 2.88 mmol/g, respectively. Excellent cyclic adsorption/desorption performance over multiple cycles is also observed. This is one of the first examples of the deployment of an advanced MOF adsorbent in a scalable, low-pressure drop gas-solid contactor. Such demonstrations are critical to the practical application of MOF materials in adsorptive gas separations, as structured contactors have many practical advantages over packed or fluidized beds.

Negative Thermal Expansion Design Strategies in a Diverse Series of Metal–Organic Frameworks

“…A further design strategy that merits exploration is the controlled incorporation of defects in MOFs, such as what has been reported in the UiO-66(Hf) structure. [49] More generally, a fundamental understanding of MOF thermal expansion is crucial to advancing their utility in a wide range of potential applications that include coated monoliths, [50] microcantilever sensors, and electronic devices. [51] In each of these scenarios, changes in temperature will arise, and a mismatch in the CTE of the MOF and its substrate material will produce residual stresses that can lead to cracking and peeling behavior or compromise the adhesion between the MOF and its interfaced layer.…”

Mechanical Properties in Metal–Organic Frameworks: Emerging Opportunities and Challenges for Device Functionality and Technological Applications

“…While fixed beds are often utilized to evaluate MOF separation performance in laboratory environments, monoliths are more practical solutions due to their improved mass and heat transfer characteristics and lower pressure drops at high flow rates . Amine‐functionalized MOF films of mmen‐M 2 (dobpdc) (M = Mg and Mn) supported on monolith contactor substrates have been investigated for CO 2 capture from simulated flue gas, and producing MOF coatings with suitable mechanical adhesion properties to withstand the activation heating treatment was found to be a challenge . In this regard, the low coefficient of thermal expansion of cordierite makes it an attractive material for monoliths to help avoid film delamination issues similar to those shown in Figure b.…”

Carbon Hollow Fiber‐Supported Metal–Organic Framework Composites for Gas Adsorption

“…[18,19] On the basis of the obtained results,i tw as concluded that al ayer-by-layer (LBL) methodf ollowed by as econdary growth step is as uitable coating method for MOF-74 film, whereas for UTSA-16 in situ dip-coating was found to be ab etter coating procedure that yields higher MOF loading. Theg rowth of amine-functionalized Mg 2 (dobpdc)o na-alumina wash-coated cordierite monolith was attempted by Darunte et al [20] through seedingo ft he monolith surfacew ithM gO first, then con-vertingittoM g 2 (dobpdc) in as ubsequent step.…”