High performance novel nanoadsorbents derived - natural cellulose fibers for superior CO2 adsorption and CO2 / CH4 separation

Abstract

ABSTRACT Currently dioxide carbon and methane as the most important greenhouse gases are constantly being emitted to the atmosphere. Thus, to reduce the detrimental effects resulting from these gases, they must be captured and separated. In this regard, novel and low- cost nanoadsorbents based on cotton pulp, jute, and kenaf as carbon fibers were successfully synthesized and fabricated. In order to provide a micro-mesoporous structure, cotton pulp, jute, and kenaf as carbon fibers were carbonized at 600°C and then activated with KOH/C (named CP-AC, J-AC, and K-AC samples). The physicochemical properties of the fabricated nanoadsorbents were characterized by BET, FTIR, XRD, and ESEM analyses. Compared to the other nanoadsorbents used, J-AC nanoadsorbent displayed an enhanced CO2 adsorption capacity at the pressure of 1 bar (5.7 mmol/g) and 35 bar (18.4 mmol/g). The fabricated nanoadsorbents created a high surface area (up to 1978 m2/g) with a pore volume of up to 0.95 cm 3/g. Several isotherm models were utilized to investigate the adsorption behavior of gases. It was found that Dual site Langmuir-Freundlich model better fitted the experimental data. The ideal adsorbed solution theory (IAST) was employed to calculate the adsorption selectivity and with the results revealing a considerable CO2/CH4 selectivity. The results also indicated that the fabricated nanoadsorbents at low pressures compared to the nanoadsorbent used in the literature have higher adsorption capacity for CO2. To summarize, the synthesized nanoadsorbents provided an excellent adsorption capacity. Thus, they could be considered for CO2 and CH4 adsorption.