The research adsorption of Zn2+ ion with using activated carbon from gelam wood has been done. Optimum condition of adsorption was determined by variating is particle size (60, 80, 100 and 140 mesh), contact time (15, 30, 60, 90, and 120 minutes) , concentration (50, 60, 70, 80, and 90 ppm), pH (4, 7, 9). Optimum condition of adsorption was tested on liquid waste of PT. Pertamina. The measureme…