Synthesis of nanoengineered microporous activated carbon from Nerium Oleander fruit seeds for the adsorptive removal of carbon dioxide (CO2)

Anthropogenic activities like fertilization, land use changes, urbanization, and so on development had resultant in emission of uncontrollable amounts of CO2 into the atmosphere. Since the industrialization era, CO2 has increased by 40% (280 ppm in 1750–421 ppm in 2022). Therefore, the present study deals with the application of engineered low-cost activated carbon nanoporous material from Nerium Oleander fruit seeds for the adsorption of CO2 gas. These seeds are abundant in nature, easy to handle, and do not require much processing for making starting material for adsorbent. The surface area and micropore volume of the starting material and prepared materials were studied with the help of a surface area analyser, the presence of various functional groups was observed with FTIR, and its crystalline structure was assessed using XRD pattern, which suggest successful synthesis of the activated carbon material. The study demonstrates the adsorption efficiency of the adsorbents decreases with increase in temperature and flow rate, whereas the height of the adsorbent column enhances the removal of CO2. The activated carbon claims its promising adsorption capacity of 48.6 mg CO2/g at (25 °C) packed into 5 cm column height with a flow rate of 25 mL/min, which is higher than the starting material (14.1 mg CO2/g). The reusability of the activated carbon was studied for up to 4 cycles, which suggests the material was exhausted more than 50% after cycle 2 and can be reused up to cycle 2. Hence, the study suggests that the activated carbon materials prepared using Nerium Oleander seeds can be effectively used for the removal of CO2 gas for making a sustainable future. Graphical abstract