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This study investigates enhancing CO 2 capture through high polyethylene glycol (PEG) loading on alumina aerogel (Al 2 O 3 -A), comparing it with alumina cryogel (Al 2 O 3 -C) and xerogel (Al 2 O 3 -X). Focusing on sustainable carbon capture and storage (CCS), the research optimizes PEG's CO 2 adsorption by adjusting the porosity of these alumina supports. Key characterization techniques, including XRD, FESEM, FTIR, and N 2 adsorption-desorption analysis, were utilized. The study evaluated the effects of pressure, temperature, and PEG loading on CO 2 capture capacity using response surface methodology (RSM). Optimal conditions (25 °C, 9.0 bar, 61.0 % PEG) achieved a CO 2 adsorption capacity of 443 mg/g. The Hill model was most effective in describing the CO 2 adsorption, while the fractional order model accurately depicted the kinetics. Thermodynamic analysis confirmed that the adsorption process is spontaneous, exothermic, and physical. The results underscore the potential of PEG/Al 2 O 3 -A for effective CO 2 capture, highlighting its high stability, capacity, and reusability, and advancing sustainable carbon capture technologies. [Display omitted] • PEG loaded on Al 2 O 3 aerogel, xerogel, and cryogel were prepared as CO 2 adsorbents. • Effects of Al 2 O 3 texture on CO 2 adsorption performance was investigated. • 61 %PEG/Al 2 O 3 -A yielded the highest CO 2 adsorption capacity of 443 mg/g. • RSM model yielded the optimum operating conditions of P=9 bar and T=25 ℃. • The Hill and Fractional order models best fitted thermodynamic and kinetic data. [ABSTRACT FROM AUTHOR]

In this study, we successfully utilized a green chemistry approach to prepare an adsorbent by functionalizing Montmorillonite with Choline Chlroride: Urea (a Deep Eutectic Solvent) to compare CO 2 , O 2 , and N 2 adsorption. We conducted studies on the adsorption mechanism using a volumetric system at temperatures ranging from 25 to 55 °C under pressures of up to 9 bar. We assessed the effects of acid activation concentration, solvent concentration, and adsorbent mass on the CO 2 /O 2 and CO 2 /N 2 adsorption ratios (mg/mg). Characterization analyses confirmed that modification of interlayer spaces, ion exchange content, and Al/Si occurred through acid treatment and solvent impregnation. The CO 2 adsorption mechanism demonstrated a heterogeneous multilayer and chemophysical sorption nature, which was in agreement with the Hill isotherm and Ellovich kinetic model. In contrast, the O 2 and N 2 mechanisms were in agreement with a monolayer nature, which matched the Langmuir isotherm and first-order kinetic model. We achieved the optimum adsorption ratio of CO 2 /O 2 and CO 2 /N 2 at 35 °C, while the highest individual adsorption for all three gases was obtained at 25 °C. At 35 °C, 5 bar, and 0.5 g, the highest uptake adsorption was 208.6 mg/g for CO 2 , 72.6 mg/g for O 2 , and 39.3 mg/g for N 2. Thermodynamic parameters showed that the adsorption nature of CO 2 , O 2 , and N 2 was exothermic (ΔH < 0) with values of −14.49 Kj/mol, −7.74 Kj/mol, and −4.09Kj/mol, respectively. The study's experimental and modeling results showed a corresponding interpretation, which was remarkable. The adsorbent exhibited desirable renewability at adsorption/desorption cycles with remarkable uptake capacity, making it a highly potential adsorbent for CO 2 capture from flue gases. The selectivity of CO 2 towards O 2 and N 2 was almost 2.1 and 3.9, respectively. [ABSTRACT FROM AUTHOR]

In this study, Ti 3 C 2 T x was synthesized from Ti 3 AlC 2 by HF 40% and 12 M LiF + 9 M HCL in 24 hr at temperatures of 313.15 and 333.15 K. Morphology, structure, and functional groups were investigated by the XRD, SEM, EDS, and BET analyses. Under the conditions of thorium (IV) concentration of 150 mg.l−1, pH ∼ 3, temperature of 298.15 K, and contact time of 540 min, the adsorption uptake of thorium (IV) with Ti 3 C 2 T x -HF and Ti 3 C 2 T x -HF in situ was 148 and 346 mg.g−1, respectively. The 3-fold adsorption of Ti 3 C 2 T x -HF in situ was because of the larger interlayer spacing, the larger number of hydroxyl functional groups, and the larger surface area due to the synthesis with 12 M LiF + 9 M HCL. Modification of Ti 3 C 2 T x with phosphate groups was done to increase the adsorption capacity of thorium (IV). The results showed that the adsorption process of thorium (IV) with pristine and modified Ti 3 C 2 T x followed pseudo-second-order kinetics and Freundlich model heterogeneous isotherm. Thermodynamic data revealed that the adsorption process was endothermic. Examining the adsorption mechanism indicated that electrostatic reactions and inner-sphere complexation were the dominant mechanisms of the process. [Display omitted] • Synthesis strategies of Ti 3 C 2 T x MXene are introduced. • The mechanism leading to the excellent adsorption performance of Ti 3 C 2 (OH) x and Ti 3 C 2 (OH) x -KH 2 PO 4 MXene is presented. • The effect of pH, temperature, background ions, dose and contact time on the adsorption of thorium was investigated. • The behaviour of Ti 3 C 2 (OH) x and Ti 3 C 2 (OH) x -KH 2 PO 4 MXene for adsorption and desorption of thorium is discussed. • The selectivity of Ti 3 C 2 (OH) x -KH 2 PO 4 was investigated in the presence of Ce3+, Gd3+, Dy(III) and Sr cations. [ABSTRACT FROM AUTHOR]

The porous carbon adsorbent walnut-shell precursors-based biomass using the Hummer synthesis method was developed for oxidized porous carbon adsorbent. Adsorption-desorption of N 2 , high-resolution transmission electron microscopy (HRTEM), FESEM, FTIR spectra, and X-ray powder diffraction analyses were used to evaluate the morphology and structure of the specimens. The oxidized porous carbon adsorbent possessed a specific surface area (217.34 m2/g) and pore volume (0.1524 cm3/g). The oxidization process reduced the average volume of mesopores and micropores. Although the specific surface area of the oxidized sample was reduced, the oxygen adsorption capacity was improved by more than 1.4 times. Under 298 K and 9.55 bar pressure, the greatest adsorption capacities for oxygen and nitrogen were specified to be 4.11 (mmol/g) and 3.03 (mmol/g), respectively. The oxygen and nitrogen adsorption on the porous carbon closely was matched by the Fractional-order kinetic and Sips isotherm models, and thermodynamic analysis demonstrated that the physisorption process was confirmed. The improved adsorbent's oxygen adsorption selectivity was remarkable. Oxygen and nitrogen adsorption were increased by oxidized adsorbent by 40% and 14%, respectively. Ultimately, oxygen can be adsorbed by the oxidized sample with more efficiency than nitrogen gas. [Display omitted] • Oxidation process reduces the average pore size of porous carbon from 2.68 nm, which was the prototype, to 0.1524 nm. • The O 2 /N 2 adsorption capacities were determined to be 4.11/3.03 (mmol/g) at 298 K and 9.55 bar, respectively. • The presence of O-H surface functional groups on adsorbent has a positive influence oxygen gas adsorption. • Oxygen and nitrogen adsorption were increased by oxidized adsorbent by 40% and 14%, respectively. [ABSTRACT FROM AUTHOR]

Various investigations have been conducted in order to decrease worldwide carbon dioxide in recent decades. Presently, CO 2 capture applying solid sorbent has attracted attentions as a manner in which the energy consumption is relatively low. In this study, a feed forward multi-layer perceptron neural network has been developed to predict the ratio of output to input of carbon dioxide concentration ( C out /C in ) in a fluidized bed reactor applied for CO 2 capture using sodium hydroxide solid sorbent over operational conditions: temperature (25–40 °C), CO 2 volume percentage (1–2%), air flow rate (14–16 m 3 /hr) and time (0–420 s). The ANN was trained by the Levenberge-Marquardt algorithm, enhanced through the combination with Bayesian regularization technique. Regression analysis results (R 2 = 0.9838) and comparison of the ANN predicted C out /C in values with corresponding experimental data (%AARD = 1.9217) have shown high prediction ability and robustness of the developed neural network. [ABSTRACT FROM AUTHOR]

In this work, operational conditions and adsorbent properties of modified montmorillonite nanoclay (MMT) with NaOH were investigated to improve CO 2 adsorption capacity. To optimization the adsorption operational conditions, process factors e.g. reactor temperature and pressure, acid concentration for activating the surface and wt% NaOH for surface modification were evaluated through five level four factor central composite design (CCD) using RSM. According to the analysis of variance (ANOVA), wt% NaOH, pressure and temperature, respectively, were selected as the most important parameters affecting CO 2 adsorption capacity in the outlet model. The optimum values are 65 °C, 1.00 bar, 5.99 M and 39.76 % for the input variables and the value of 105.55 mg/g for the response, respectively. The study of isotherm models shows the Toth isotherm model is well suited to experimental isotherm data and shows multi-layer adsorption on heterogeneous surfaces with Gaussian energy distribution. Also, the kinetic models showed that Elovich model provides the best fit to CO 2 adsorption data. This suggests that the connection of CO 2 in the modified montmorillonite appears to be due to the formation of chemical bonds. [ABSTRACT FROM AUTHOR]