Ikhsan, Aiinsiin Azhima2021-09-232021-09-232021-01wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/10201This study aims to treat and utilize bottom ash by making it an adsorbent. Adsorbent was prepared by using microwave activation method at 100 watts with variation of activation times (1;2;3;4 and 5 minutes). The efficiency of adsorption and the determination of the optimum activation time were tested by adsorbing 50 ppm methylene blue. Bottom ash non-activated and activated by microwave compared and analyzed using SEM. The results showed that the adsorption efficiency increased with the activation process and the optimum activation time was 3 minutes, with a percentage of adsorption is 97.75%. The activation process with microwave also causes additional pores. It can be concluded that boiler bottom ash has a high adsorption efficiency against methylene blue and the activation process with microwave increases the adsorption efficiency.enadsorpsiashmicrowaveArticle