Experimental study of CO₂ adsorption using activated carbon

Abstract

The current study aimed to investigate the CO2 adsorption isotherms of activated carbon (AC), prepared from olive waste via chemical activation by H3PO4. The textural parameters, the microstructural and morphological characterization of the AC were characterized by N2 adsorption-desorption, SEM and XRD. The AC presented the best textural properties with a BET surface area of 1565 m2 g−1 and a micropore volume of 0.649 cm3 g−1. The CO2 adsorption was measured with a volumetric method at three various temperatures: 298 K, 308 K and 318 K. Different models, such as the Langmuir and Freundlich isotherms, were applied to model the CO2 adsorption. Based on the correlation coefficient (R2), the Langmuir model provided a the best fit with the experimental data. Different thermodynamic functions, such as Gibbs free energy and entropy, were calculated using Van Hoff’s formulation. These thermodynamic parameters indicated that the CO2 adsorption is an exothermic and spontaneous process. The results obtained in this study can serve as a benchmark while designing an adsorption-based gas storage system. the Freundlich

Experimental study of CO2 and N2 adsorption on activated carbon

“…Structural characterization of the AC Figure 1 gives the XRD diffraction of the AC which presents two peaks occurringat 2θ roughly 25°and 42°. These peaks are related to the (001) and (101) planes of the hexagonal structure of graphite [6].…”

“…The activated carbon which is utilized in this research is obtained from Tunisian olive waste. [6]. The olive waste has been treated with 85% of phosphoric acid (H 3 PO 4 ) in a weight ratio of 1:1, and the mixture was then heated in an electric oven for 24 h at 100 °C.…”

“…In this context different adsorbent are used such as clay, zeolite and activated carbon [5]. Activated carbon is a promising adsorbent since it has a high surface and a great adsorption capacity [6]. The adsorption technique using AC as a raw material is used extensively for the gas separation, purification and in the gas storage systems [7].…”

Optimization of CO2 Sorption onto Spent Shale with Diethylenetriamine (DETA) and Ethylenediamine (EDA)

“…From the values displayed in Table 6 , it is observed that the ΔH values were negative for non-modified samples, which confirms an exothermic (physisorption) reaction between the CO 2 and the sorbent [ 22 ], while positive values were obtained for the amine-modified samples, which indicates an endothermic reaction. An endothermic reaction occurs when a large amount of energy is required to desorb an adsorbate (CO 2 ) during a sorption process.…”

“…The N 2 gas was passed into the tube furnace for 30 min to replace the air and moisture, after which its temperature was increased to 800 °C at the rate of 2 mL min −1 for 4 h. The cooled char generated was designated as USQ 06_800C, USM 3_800C, USM 5_800C, and US 6_ 800C. Emulating the procedure employed by Almoneef et al [ 22 ], 20 g of each char was added to 60 mL of DETA and EDA separately in conical flasks and stirred continuously in a water shaking bath for 4 h at 70 °C then filtered and washed with 120 mL of methanol. The slurry was finally dried at 80 °C for complete impregnation of the amine functional group to the surface of the samples.…”