This paper describes the preparation of O-enriched porous carbonaceous adsorbents derived from low cost, abundantly available polyethylene terephthalate (PET) waste with high carbon content by directly carbonising at different temperatures (500–800 °C) and then chemically activating using variable impregnation ratios of KOH to carbon. The prepared carbon adsorbents were characterized for their textural and surface chemical properties using nitrogen sorption, CHN, FTIR, XRD, SEM, HRTEM, and XPS techniques. Further, to assess their CO₂ adsorption-desorption performance under dynamic conditions, breakthrough experiments were conducted in a fixed-bed adsorption set up. Porous carbon obtained at 700 °C with KOH to carbon mass ratio of 3 (Act-3-700) exhibited best textural properties with BET surface area of 1690 m²g^-1 and micropore volume of 0.78 cm³ g⁻¹ and showed highest CO₂ uptake of 1.31 mmol g⁻¹ at 30 °C and 12.5% CO₂ concentration. Four adsorption–desorption cycles establish the adsorbent's remarkable stability and regeneration. Furthermore, fractional order kinetic model explained the CO₂ adsorption kinetics and Freundlich isotherm showed superior fit with the adsorption equilibrium data suggesting heterogeneous nature of the adsorbent surface. Negative values of Gibbs free energy ΔG° and adsorption enthalpy ΔH° indicate the spontaneous and exothermic nature of adsorption process.

本文介绍了如何通过在不同温度（500-800°C）下直接碳化，然后使用可变的浸渍率进行化学活化，来制备由低成本，可大量利用的，具有高碳含量的聚对苯二甲酸乙二醇酯（PET）废料制成的富含O的多孔碳质吸附剂。 KOH转化为碳。使用氮气吸附，CHN，FTIR，XRD，SEM，HRTEM和XPS技术对制得的碳吸附剂的结构和表面化学性质进行表征。此外，为了评估它们在动态条件下的CO ₂吸附-脱附性能，在固定床吸附装置中进行了突破性的实验。在700°C下以KOH与碳质量比为3（Act-3-700）获得的多孔碳表现出最佳的织构性质，BET表面积为1690 m² g ^-1和0.78 cm ³  g ^-1的微孔体积， 在30°C和12.5％CO ₂浓度下显示最高的CO ₂吸收1.31 mmol g ^-1。四个吸附-解吸循环确定了吸附剂的出色稳定性和再生能力。此外，分数阶动力学模型解释了CO ₂吸附动力学，Freundlich等温线显示出与吸附平衡数据的高度吻合，表明吸附剂表面具有非均质性质。吉布斯自由能ΔG°和吸附焓ΔH°的负值表示吸附过程的自发性和放热性。