Jabon (Anthocephalus cadamba) is the a one of native tree species of Indonesia. The utilization of Jabon was focused on wood production that makes other part such as Jabon seed was underutilized. This study was focused on Jabon seed as biomass for adsorbent of mercury(ii) ion. Jabon seed was used as a source of activated carbon by chemical activator method using NaOH as an activator. Jabon seed…