Performance of activated carbon derived from tea twigs for carbon dioxide adsorption

Abstract

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 h and 3 h 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 h with a ratio of activator solution and precursor 4:1 using KOH concentration of 40 %. The highest surface area was obtained 1403 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.