Preparation of Chemically Activated Porous Carbon Derived from Rubber-Seed Shell for CO2 Adsorption

The utilization of agricultural biomass for the synthesis of carbonaceous adsorbents is an active research topic because of a wide range of precursors and good adsorption properties of the resulting adsorbent materials. Rubber-seed shell (RSS) is a suitable precursor for the synthesis of activated carbon (AC) due to its naturally high carbon content. In addition, it is available in large quantities due to the growing rubber plantations in Malaysia. In this work, activated carbon is produced via chemical activation of RSS for CO2 adsorption. A two-step and a modified three-step activation method using K2CO3 as an activating agent are used for the preparation of RSS-derived AC. AC samples prepared by both techniques are compared based on structural properties and CO2 adsorption capacity to identify the more effective synthesis method. Carbon content increased from 48.40 wt.% in the untreated RSS to >77 wt.% in prepared AC samples, indicating successful activation. BET surface area for AC2 and AC3 was 474.7 m2/g and 683.4 m2/g, respectively. The highest CO2 adsorption capacity of 60.06 mg/g at 25 °C was obtained for AC3. Overall, AC produced by the three-step activation has superior structural properties and CO2 adsorption performance.