Adsorption of SO₂, NO, and CO₂ on Activated Carbons: Equilibrium and Thermodynamics

Abstract

To investigate the coadsorption of SO 2 , NO, and CO 2 from the flue gas, adsorption equilibrium tests of SO 2 , NO, and CO 2 on coconut shell activated carbon (SAC) and coal-based activated carbon (CAC) were conducted at the temperatures (323, 343, and 363) K by the static volumetric method. The equilibrium data were well fitted by the Toth model. Henry's constant was calculated by the Virial model; the results showed that adsorption affinity followed the order SO 2 > CO 2 > NO > N 2 on SAC, and SO 2 > NO > CO 2 > N 2 on CAC. Then thermodynamics data, including Gibbs' free energy, entropy, and enthalpy, were also calculated to characterize adsorption behaviors. SO 2 had the highest degree of freedom, while CO 2 formed a most regular configuration. The efficiency of molecule packing in CAC was lower than that in SAC. Finally, competitive adsorption of different flue gas components was predicted by the extended Toth model. The adsorption amount followed the order CO 2 > N 2 > SO 2 > NO for both adsorbents. SAC had better adsorption property than CAC in the multicomponent adsorption.

Synthesis, Characterization, Adsorption and Thermodynamic Studies of Pure and Binary Co2-N2 Mixtures on Oxygen Enriched Nanostructured Carbon Adsorbents

“…The average value of isosteric heat of adsorption (Q st ) for CO 2 on EZ-700 was calculated to be ca. 34.82 kJ mol -1 which is in agreement with the available value in thre literature for carbon adsorbents (Caldwell et al, 2015;Shen et al, 2010;Yi et al, 2014). An almost constant Q st value was seen at different surface loadings.…”

“…This indicates a more effective molecular packing, and higher amount of release of heat. Similar observations were seen for activated carbons like Maxsorb III (-20.37 kJ mol -1 ) (Saha et al, 2011), coal based activated carbon (21.89 kJ mol -1 ) (Yi et al, 2014), and activated carbon beads (-23.17 kJ mol -1 ) (Shen et al, 2010).…”

Thermodynamics and regeneration studies of CO2 adsorption on activated carbon

“…Henry's constant ( K ), incorporating q m and b , is usually applied to evaluate adsorption affinity which is inextricably linked with the interaction between the molecules of adsorbate and the surface of adsorbent when the pressure was low . As expected, the decreasing of Langmuir equilibrium constant b and Henry's constant K with the increase of temperature demonstrates the exothermic nature of CO 2 adsorption process, presenting the weaker adsorption affinity as the temperature increases.…”

The Study of Adsorption Process of H2s, Co2 and No2 From Natural Gas by Zeolite

“…Этот способ позволяет упростить конструкцию системы очистки, так как для регенерации адсорбента, которую можно вести очищенным природным газом, подогретым в теплообменнике, не требуется специального оборудования. Недостаток этого способа состоит в дополнительном расходе природного газа на регенерацию адсорбентов [1][2][3].Подготовка газа, а также очистка газа адсорбционным способом на практике нашло широкое применение и имеет ряд преимуществ. Это высокие экологические показатели, большая глубина осушки, низкий удельный расход адсорбента, а также хорошие эксплуатационные характеристики установок.…”

“…Этот способ позволяет упростить конструкцию системы очистки, так как для регенерации адсорбента, которую можно вести очищенным природным газом, подогретым в теплообменнике, не требуется специального оборудования. Недостаток этого способа состоит в дополнительном расходе природного газа на регенерацию адсорбентов [1][2][3].…”