(269c) Enhanced CO2 Adsorption through Triethylenetetramine Functionalized Cu-CNF Supported on Porous Carbon Matrix: Experimental Investigations, Isotherm, and RSM Modelling

Certain drastic changes in the climate and living ecosystems have caused serious threats to human health and living organisms on earth. To reduce the threats at its minimal level, carbon dioxide (CO₂) capture from various industries and even directly from the atmosphere has gained wide spread attentions. In past decades, CO₂ capture route was based on the scrubbing of CO₂ through various amine solutions. Herein, we demonstrate a new strategy to enhance CO₂ adsorption efficiency by using amine-treated carbon nanomatrices supported on porous activated carbon fibers (ACFs) at low pressure. First of all, we synthesized novel catalytic chemical vapour deposition grown carbon nanomatrices supported on ACF (Cu-CNF/ACF). The synthesized material was further impregnated with triethylenetetramine (TETA) at an optimized concentration of 30% with an aim to further improving its adsorption capacity. Studies were also performed with pure ACF for comparison. The parent ACF and amine treated Cu-CNF/ACF adsorbents were carefully characterized by various approaches, viz., HR-XRD, Micro Raman, FT-IR, FE-SEM, TEM, EDS, TGA, XPS, BET, and elemental C-H-N-S analysis. The CO₂ capture behaviour of materials at various stages was examined on iSorpHP2 adsorption equipment under pressure and temperature swing circumstances. The pressure and temperature ranges were varied from 0 to 30 bar and 25 to 80 ᵒC, respectively. Response surface methodology (RSM) based on the Box-Behnken design (BBD) was exploited to design experiments and also to investigate the optimum conditions for the desirable response i.e. CO₂ adsorption performance. Three distinct variables such as temperature, CO₂ partial pressure, and TETA loading were found to affect the CO₂ adsorption performances. Additionally, CO₂ adsorption was mathematically modelled using numerous isotherm models. Cu-CNF/ACF treated with 30%TETA exhibited the highest CO₂ adsorption capacity (4.876 mmol/g) as compared to pure ACF substrate (2.448 mmol/g) at 25 ᵒC and 1 bar partial pressure. Regeneration and reusability studies were further performed to explore the CO₂ adsorption capacity of the regenerated samples. Reusability study showed that a marginal loss of CO₂ adsorption capacity (4.876 mmol/g to 4.341 mmol/g) occurred post eight test runs when Cu-CNF/ACF treated with 30%TETA was used for CO₂ adsorption study. Thus, with further optimization of the experimental conditions, the current material may act as an excellent adsorbent for the adsorption of several other pollutants such as methane (CH₄), sulphur dioxide (SO₂), and many others.