Higher Institution of Centre of Excellence (HICoE) Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Department of Chemical Engineering, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak, Malaysia.
Chemical Engineering Department, COMSATS University Islamabad (CUI), Lahore Campus, Defence Road, Off Rawind Road, Lahore, Pakistan.
Environ Sci Pollut Res Int. 2021 Jul;28(26):33967-33979. doi: 10.1007/s11356-020-08823-z. Epub 2020 Apr 25.
The volumetric adsorption kinetics of carbon dioxide (CO) onto the synthesized palm kernel shell activated carbon via single-stage CO activation and commercial Norit® activated carbon were carried out at an initial pressure of approximately 1 bar at three different temperatures of 25, 50, and 100 °C. The experimental kinetics data were modelled by using the Lagergren's pseudo-first-order model and pseudo-second-order model. Comparing these two, the non-linear pseudo-second-order kinetics model presented a better fit towards CO adsorption for both adsorbents, owing to its closer coefficient of determination (R) to unity, irrespective of the adsorption temperature. In addition, kinetics analysis showed that the corresponding kinetics coefficient (rate of adsorption) of both activated carbons increased with respect to adsorption temperature, and thereby, it indicated higher mobility of CO adsorbates at an elevated temperature. Nevertheless, CO adsorption capacity of both activated carbons reduced at elevated temperatures, which signified exothermic and physical adsorption (physisorption) behaviour. Besides, process exothermicity of both carbonaceous adsorbents can be corroborated through activation energy (E) value, which was deduced from the Arrhenius plot. E values that were in range of 32-38 kJ/mol validated exothermic adsorption at low pressure and temperature range of 25-100 °C. To gain an insight into the CO adsorption process, experimental data were fitted to intra-particle diffusion model and Boyd's diffusion model, and findings revealed an involvement of both film diffusion and intra-particle diffusion during CO adsorption process onto the synthesized activated carbon and commercial activated carbon.
二氧化碳（CO）在单级 CO 活化和商业 Norit®活性炭上的合成棕榈仁壳活性炭的体积吸附动力学在约 1 巴的初始压力下，在 25、50 和 100°C 的三个不同温度下进行。实验动力学数据通过 Lagergren 拟一级模型和拟二级模型进行建模。比较这两种模型，非线性拟二级动力学模型对两种吸附剂的 CO 吸附具有更好的拟合度，因为其决定系数（R）更接近 1，而与吸附温度无关。此外，动力学分析表明，两种活性炭的相应动力学系数（吸附速率）均随吸附温度的升高而增加，这表明在较高温度下 CO 吸附质的迁移率更高。然而，两种活性炭的 CO 吸附容量在升高的温度下降低，这表明是放热和物理吸附（物理吸附）行为。此外，通过从 Arrhenius 图推断出的活化能（E）值，可以证实两种碳质吸附剂的过程放热。E 值在 32-38 kJ/mol 的范围内验证了在 25-100°C 的低压和温度范围内的放热吸附。为了深入了解 CO 吸附过程，将实验数据拟合到内扩散模型和 Boyd 扩散模型中，结果表明在 CO 吸附到合成活性炭和商业活性炭的过程中，涉及到了膜扩散和内扩散。
