Layered Double Hydroxides-Based Mixed Metal Oxides: Development of Novel Structured Sorbents for CO₂Capture Applications

Abstract

Layered double hydroxide (LDHs)-based mixed metal oxides (MMOs) are widely studied as the medium to high temperature (200–400 °C) CO2 capture sorbents. However, most of the studies are carried out using the powdered samples. To upgrade these sorbents for industrial-scale CO2 capture, it is important to move away from the powdered form and develop structured sorbents. Moreover, the CO2 capture properties of these sorbents need to be improved in terms of capture capacity and cycling stability. Here we are utilizing a modified amide hydrolysis method to improve the CO2 capture capacities of LDHs-based MMOs. Subsequently, aqueous exfoliation coupled with the freeze-drying technique was utilized to develop LDHs-based novel MMOs. Exfoliated LDH nano sheets were pelletized (2 mm) to circumvent the challenges associated with powder samples when used in industrial-scale applications. The obtained pellets have an average crushing load of 11.1 N and 4.3 MPa of compressive strength, which indicate their good mechanical stability. The MMOs pellets showed a narrow distribution of pores (8–10 nm) with very good surface area (264 m2/g) and pore volume (1.27 cm3/g). They also had much improved CO2 capture capacities at ambient pressure and both low (2.17 mmol/g, 30 °C) and medium temperature (1.43 mmol/g, 200 °C), as compared to previously reported pristine MMOs powder samples. The pelletized structured sorbents also outperformed commercial LDH-based pellets by several fold.

A Review on SAPO‐34 Zeolite Materials for CO2 Capture and Conversion

“…Finally, the materials of the adsorbents must be economically viable and readily available. [103] Numerous adsorbents have been reported for CO 2 capture, including zeolites, [93,95,104] ceramics, [105,106] carbonates, [107,108] metal and metal oxides, [24,25] carbonaceous materials, [100,109,110] amines, hydroxides, [111,112] polymers, [113,114] ionic liquids, [115] covalent organic frameworks, [116] and metal-organic frameworks (MOFs). [117][118][119][120][121][122][123][124][125][126][127] Acid-base neutralization reactions also play a key role in capturing CO 2 .…”

Perspective on Sorption Enhanced Bifunctional Catalysts to Produce Hydrocarbons

“…LDH-based mixed metal oxides (MMOs) have been widely investigated because of their physicochemical properties. − LDHs are represented by the general formula [M 2+1– x M 3+ x (OH) 2 ] x +(A– x / n ) y H 2 O, where M 2+ = Mg, CO, Ni, Ca, or Zn, M 3+ Al, Fe, or Ga, A = anion (organic or inorganic ions), 0.15 ≥ x ≤ 0.33 and 0.5 ≥ y ≤ 1.0. ,, LDH-derived MMOs have been considered as ideal candidate materials for intermediate temperature CO 2 sorbents because of their fast sorption/desorption kinetics, high theoretical CO 2 capture capacity, ease of preparation, and low cost . Manohara et al synthesized LDHs with a mixed morphology using a modified amide hydrolysis method .…”

A Role for Newly Developed Sorbents in Remediating Large‐Scale Oil Spills: Reviewing Recent Advances and Beyond

“…Specifically, the hierarchically porous structure of sorbent can hold some these viscous oils which results in a high oil sorption capacity. [124][125][126][127][128][129][130][131][132][133] On the other hand, the absorption mechanism happens not only on the surfaces but mostly inside the polymer matrix with an extensive polymer matrix swelling (Figure 4B). The Flory−Rehner theory (Equation ( 1)) can be used to determine the network structure (i.e., crosslinking density and molecular weight between cross-links) and provide the structure−property relationships.…”