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Piperazine‐modified activated alumina as a novel promising candidate for CO 2 capture: experimental and modeling
Author(s) -
Fashi Fatemeh,
Ghaemi Ahad,
Moradi Peyman
Publication year - 2019
Publication title -
greenhouse gases: science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.45
H-Index - 32
ISSN - 2152-3878
DOI - 10.1002/ghg.1829
Subject(s) - adsorption , piperazine , enthalpy , gibbs free energy , freundlich equation , sorbent , chemistry , exothermic reaction , thermodynamics , atmospheric temperature range , activation energy , exothermic process , activated carbon , kinetic energy , materials science , organic chemistry , physics , quantum mechanics
Abstract In this research, the CO 2 adsorption process was studied using modified activated alumina with a piperazine solution as a novel sorbent. Activated alumina was modified with a piperazine solution concentration in the range of 1–4 wt%. Adsorption experiments were performed to evaluate the operating parameters, including CO 2 pressure in the range of 2–8 bar, adsorbent dosage in the range of 0.5–2 g, temperature in the range of 25–85°C and adsorbent mesh in the range of 200–800 micron. Maximum adsorption capacity (222.01 mg CO 2 /g modified activated alumina) was determined at a temperature of 25°C, pressure of 8 bar, and adsorbent dosage of 0.5 g, with a piperazine solution of 2 wt%. The results of the experiments showed that the rate of CO 2 adsorption increases with increasing pressure and decreasing temperature. The Freundlich isotherm model with correlation coefficient of 0.999 was found to be the best for fitting the CO 2 adsorption isotherm data. The kinetic study also indicated that the Elovich model fits the experimental kinetic data well. The negative values of Gibbs free energy change ( Δ G°) and enthalpy change ( Δ H°) show that the reaction is spontaneous in nature and exothermic. The negative value of entropy change ( Δ S°) shows a reduction in the irregularity of the adsorption process. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.