Activated Carbon for CO 2 Adsorption from Avocado Seeds Activated with NaOH: The Significance of the Production Method.

The rise in atmospheric greenhouse gases like CO 2 is a primary driver of global warming. Human actions are the primary factor behind the surge in CO 2 levels, contributing to two-thirds of the greenhouse effect over the past decade. This study focuses on the chemical activation of avocado seeds with sodium hydroxide (NaOH). The influence of various preparation methods was studied under the same parameters: carbon precursor to NaOH mass ratio, carbonization temperature, and nitrogen flow. For two samples, preliminary thermal treatment was applied (500 °C). NaOH was used in the form of a saturated solution as well as dry NaOH. The same temperature of 850 °C of carbonization combined with chemical activation was applied for all samples. The applied modifications resulted in the following textural parameters: specific surface area from 696 to 1217 m 2 /g, total pore volume from 0.440 to 0.761 cm 3 /g, micropore volume from 0.159 to 0.418 cm 3 /g. The textural parameters were estimated based on nitrogen sorption at -196 °C. The XRD measurements and SEM pictures were also performed. CO 2 adsorption was performed at temperatures of 0, 10, 20, and 30 °C and pressure up to 1 bar. In order to calculate the CO 2 selectivity over N 2 nitrogen adsorption at 20 °C was investigated. The highest CO 2 adsorption (4.90 mmol/g) at 1 bar and 0 °C was achieved.