Adsorption Mechanism Analysis and Performance Study of Cork‐Based Activated Carbon on Methylene Blue

Abstract The preparation of cork‐based activated carbon was carried out using a one‐step chemical activation method to determine the optimal conditions for its preparation. The performance of the cork‐based activated carbon was characterized to investigate the effects of different conditions on its adsorption performance and adsorption mechanism. The results showed that as the carbonization temperature and impregnation ratio increased, the number of high chemical reactivity oxygen‐containing functional groups on the surface of the cork‐based activated carbon significantly decreased, thus affecting the pore size of the activated carbon; the specific surface area gradually increased, primarily showing a mesoporous distribution, which is beneficial for enhancing adsorption capacity. The optimal preparation temperature was ultimately determined to be 600 °C, with an impregnation ratio of 1:3; the optimal adsorption conditions were established at an addition of 6 g/L and an adsorption time of 5 min, during which the removal rate of methylene blue was found to be 100%. The adsorption process of cork‐based activated carbon for methylene blue followed the pseudo‐second‐order kinetic model, with the rate‐limiting step being chemical adsorption, while both intra‐particle diffusion and film diffusion jointly controlled the adsorption rate of methylene blue. The adsorption process mainly involved monolayer adsorption, along with electrostatic attraction.