Roles of London Dispersive and Polar Components of Nano-Metal-Coated Activated Carbons for Improving Carbon Dioxide Uptake

Seul-Yi Lee,Soo-Jin Park,Jong-Hoon Lee,Yeong-Hun Kim,Kyong-Yop Rhee

doi:10.3390/coatings11060691

Seul-Yi Lee, Soo-Jin Park + Show 3 more

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https://doi.org/10.3390/coatings11060691

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Journal: Coatings	Publication Date: Jun 9, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: Inha University, Kyung Hee University

Abstract

Adsorption using carbonaceous materials has been considered as the prevailing technology for CO2 capture because it offers advantages such as high adsorption capacity, durability, and economic benefits. Activated carbon (AC) has been widely used as an adsorbent for CO2 capture. We investigated CO2 adsorption behaviors of magnesium oxide-coated AC (MgO-AC) as a function of MgO content. The microstructure and textural properties of MgO-AC were characterized by X-ray diffraction and nitrogen adsorption–desorption isotherms at 77 K, respectively. The CO2 adsorption behaviors of MgO-AC were evaluated at 298 K and 1 atm. Our experimental results revealed that the presence of MgO plays a key role in increasing the CO2 uptake through the interaction between an acidic adsorbate (e+) and an efficient basic adsorbent (e−).

Highlights

Surface-free energy, which describes the physical phenomenon caused by intermolecular interaction at an interface, may be considered as the sum of two components: a dispersive component corresponding to London attraction and a nondispersive component that includes all other types of interactions, such as Debye inductive force, Keesom orientational forces, hydrogen bonding, and Lewis acid–base interaction
Before loading magnesium oxide (MgO) onto the surfaces of the Activated carbon (AC), the ACs were purified by acid treatment using 5 M nitric acid solution to enhance the interfacial adhesion between magnesium and the AC surfaces
We found that MgO is predominantly formed during post-oxidation at 300 ◦ C due to the reaction with air

Summary

Introduction

Surface-free energy, which describes the physical phenomenon caused by intermolecular interaction at an interface, may be considered as the sum of two components: a dispersive component corresponding to London attraction and a nondispersive (or polar) component that includes all other types of interactions, such as Debye inductive force, Keesom orientational forces, hydrogen bonding, and Lewis acid–base interaction. In the early 1960s, adsorption studies reported by Fowkes [4] and Graham [5] defined equilibrium spreading pressure (πe ) and surface-free energy of solids (γS ) using simple adsorbates such as nitrogen, argon, and hydrocarbon. Park and Brendle [3] reported that an increase in the London dispersive component of surface-free energy (γSL ) is one of the main factors in the adsorption capacity, along with the specific surface area of the adsorbent including practically nonpolar adsorbents (for example, carbon materials). The specific (or polar) component of the surface-free energy (γSSP ) on the adsorbent is another important factor in increasing the strength of adsorption through acid–base interaction [6]. The CO2 molecule may interact with the electric fields of carbonaceous materials, leading to increased acid–base interaction [10]

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