Development and study of activated carbon prepared from papaya seeds

Activated carbons were prepared using papaya seeds as raw materials. The present study aims to demonstrate and illustrate the following aspects: first the development of activated carbon; second the impact of different thermal treatment condition on the physical and chemical characteristic of the activated carbon; third the corresponding liquid phase adsorption test as evaluated by iodine and methylene blue as adsorbates. Increasing burn-off of the samples raised the BET surface area, iodine uptake and methylene blue removal efficiency of the activated carbons. These were clearly illustrated by SEM micrographs that porous structures were progressively developed. However, the surface chemistry of the activated carbon under different thermal treatment had neglected variance due to the pH controlled during the preparation process. Activated carbon prepared at 600°C and 45 minutes had the highest BET surface area, iodine number and methylene blue removal efficiency. The BET surface area was 219.056 m²/g and the iodine number was 81.600 mg/g. The methylene blue adsorption results were well fitted in the Langmuir isotherm, with the highest removal efficiency recorded at 62 %. Higher activation temperature tends to produce optimum result than longer activation time, suggested that papaya seeds derived activated carbon with higher surface area and better adsorption capacity can be developed by considering higher activation temperature.