This research aims to produce activated carbon from molasses via a chemical activation process with potassium hydroxide (KOH) and a microwave heating process which consumes less energy and provides more rapid and uniform heat distribution than a conventional heating. The obtained activated carbon was then characterized with BET SEM and FTIR. It exhibited a large specific surface area of 1631 m2/g and a total pore volume of 1.124 cm3/g consisting of mesopore and micropore. In addition the active functional groups were also found on the surface of the activated carbon. Thus it was brought for the adsorption test with methylene blue. It was found that the adsorption capacity of the activated carbon increased with time and reached the equilibrium within 8 hours. The adsorption data of the activated carbon were corresponded to Langmuir isotherm with the highest adsorption capacity of 370.37 mg/g. The adsorption kinetic of the activated carbon exhibited pseudo-second order reaction suggesting to the chemisorption phenomenon. From the thermodynamic study it revealed that the adsorption process were endothermic and spontaneous reactions.

The pomelo peels charcoal was successfully prepared by traditional charcoal burning and its adsorption of methylene blue was investigated. The influences of methylene blue adsorption including contact time and methylene blue initial concentration were studied at room temperature. The adsorption rate initially increased rapidly until 24 h and 600 mg/L of methylene blue initial concentration. The further increase in contact time and methylene blue initial concentration did not significantly increase the adsorption due to it reached equilibrium. Kinetic of adsorption were investigated that the pseudo-second order model best described adsorption kinetic data. The adsorption isotherms were evaluated and the data correlated with Langmuir adsorption model with the maximum adsorption capacity was found to be 166.67 mg/g. The adsorption of pomelo peel charcoal was studied comparing to other adsorbents at the same experimental conditions. The results showed higher adsorption of pomelo peel charcoal than dried pomelo peel longan wood charcoal coconut shell charcoal litchi wood charcoal and tamarind wood charcoal respectively.