An activated carbon material for removing a contaminant from a liquid. The activated carbon material can be a plurality carbon grains that have a pore volume of approximately 0.1 milliliters per gram (mL/g) in the range of less than about 15 angstroms in width. The carbon grains can also have or contain a nitrogen-containing species having a concentration of more than 2 atomic percent nitrogen. A plurality of the carbon grains can be used to make a contactor that is operable to remove or reduce perchlorate having a concentration of 20 parts per billion (ppb) to less than 4 ppb from 4,500 bed volumes of water with the nitrogen-containing species leaching off of the carbon grains less than 0.1 mg/L. The activated carbon material can also be electrochemically regenerated.