Activated carbon from agro-industrial waste, namely tea twigs derived from the processing of Camellia Sinensis branches, using a potassium hydroxide activator for CO2 adsorption has been conducted in this study. Various carbonization temperatures (4000C and 5000C) and heating times of 1 hour and 3 hours were used in this study. The concentration of potassium hydroxide (40% and 60%) and the ratios of activator solutions to carbon precursor made from pyrolysis of tea twigs (2:1 and 4:1) were varied for the chemical activation process. The effectiveness results of the obtained activated carbon were characterized through using Brunauer-Emmett-Teller analyzer and Temperature Programme Desorption-CO2 to determine the surface area and capacity maximum of CO2 adsorption. The optimum condition for the synthesis of activated carbon that produces high surface area was obtained at sample CCS 400/1 A2B1 where biochar carbonized at temperature of 400°C kept for 1 hour with a ratio of activator solution and precursor 4:1 using KOH concentration of 40%. The highest surface area was obtained 1,403 m2 g-1 with pore volume 0.9 m2 g-1 and pore size 1.11 nm and proved the presence of microporous areas in produced activated carbon. The maximum CO2 adsorption capacity obtained in this study was 5.1573 mmol g-1. This result could be related to the higher amount of microporous present in the activated carbon that facilitates the access of CO2 to the active sites at the pores of activated carbon.
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