Adsorption Equilibrium, Thermodynamic, and Kinetic Study of O₂/N₂/CO₂ on Functionalized Granular Activated Carbon

Abstract

A volumetric system was used to assess carbon-based adsorbents for evaluation of the gas separation, equilibrium, and kinetics of oxygen (O 2 ), nitrogen (N 2 ), and carbon dioxide (CO 2 ) adsorption on granular activated carbon (GAC) and functionalized GAC at 298, 308, and 318 K under pressures up to 10 bar. The effects of ZnCl 2 , pH, arrangement of the pores, and heat-treatment temperature on the adsorptive capabilities of O 2 , N 2 , and CO 2 were evaluated. High-performance O 2 adsorption resulted with a fine sample (GAC-10-500) generated with a 0.1 wt % loading of ZnCl 2 . The optimal sample structure and morphology were characterized by field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, and powder X-ray diffraction. On the basis of the adsorption–desorption results, the fine GAC provides a surface area of 719 m 2 /g. Moreover, it possessed an average pore diameter of 1.69 nm and a micropore volume of 0.27 m 3 /g. At 298 K, the adsorption capacity of the GAC-10-500 adsorbent improved by 19.75% for O 2 but was not significantly increased for N 2 and CO 2 . Isotherm and kinetic adsorption models were applied to select the model best matching the studied O 2 , N 2 , and CO 2 gas uptake on GAC-10-500 adsorbent. At 298 K and 10 bar, the sip isotherm model with the highest potential adsorption difference sequence and gas adsorption difference compared with pure GAC adsorbent as O 2 > N 2 > CO 2 follows well for GAC-10-500. Eventually, the optimal sample is more effective for O 2 adsorption than other gases.

Synthesis and characterization of waste Styrofoam hypercrosslinked polymer as an adsorbent for CO2 capture

“…Where q e represents the capacity of CO 2 adsorption (mmol/g), q m is the greatest amount of CO 2 that can be adsorbed (mmol/g), P is the pressure at equilibrium (bar), and K T A B L E 4 Parameters of kinetic models determined for CO 2 uptake by WEPS 92 The magnitude of ΔH 0 has been reported to be 20 (kJ/mol) for physisorption and between 80 and 200 (kJ/mol) for chemical adsorption. 93,94 As a consequence, the calculated ΔH 0 (in Table 5) suggests that CO 2 adsorption occurs through physisorption, which is consistent with lowering the amount of CO 2 adsorbed at increased temperatures (as shown in Figure 8). Additionally, when the temperature rises, ΔG 0 (negative value) decreases (Table 5).…”

“…Negative values indicate that the CO 2 adsorption process is exothermic, but negative values indicate that the adsorbate molecules are highly organized during adsorption 92 . The magnitude of has been reported to be 20 (kJ/mol) for physisorption and between 80 and 200 (kJ/mol) for chemical adsorption 93,94 . As a consequence, the calculated (in Table 5) suggests that CO 2 adsorption occurs through physisorption, which is consistent with lowering the amount of CO 2 adsorbed at increased temperatures (as shown in Figure 8).…”

“…Moreover, the reduction in the value confirms the presence of physical adsorption (given in Table 3). 93,94 According to the findings, the adsorption process is multilayer, with CO 2 adsorbed and permeating the surface and interior layers of the adsorbent 92 . The Sips model prioritizes more effective contact sites, implying that the adsorbent's surface is heterogeneous and that the inhomogeneous distribution of energy inactive sites results in multilayer CO 2 adsorption.…”

Comprehensive analysis of cationic dye removal from synthetic and industrial wastewater using a semi-natural curcumin grafted biochar/poly acrylic acid composite hydrogel

“…- Internal diffusion: the propagation of adsorbate species from the liquid film to the solid adsorbent's surface. 75…”

Modeling and Optimizing N/O-Enriched Bio-Derived Adsorbents for CO2 Capture: Machine Learning and DFT Calculation Approaches

“…Biomass carbon precursors (BCPs) have favorable advantages as being well known, highly accessible, inexpensive, and sustainable in preparing tailored porous CO 2 solid adsorbents. − Biomass-derived activated carbon (BAC) is mostly accomplished by thermochemical conversion and synergistic chemical/physical activating processes (carbonization, hydrothermal treatment, oxidization, etc.) that are applied to different BCPs. , The advanced physicochemical features of BACs mostly rely on the type and mass ratio of activation agents (e.g., KOH, ZnCl 2 , H 2 O 2 , NaNH 2 , K 2 CO 3 ) and tuning parameters of thermochemical conversion (such as activation temperature, heating rate, gas flow rate, etc.…”