Graphical Abstract: The adsorption process of ammonia ions and ammonium from aqueous solutions on the intact activated carbon obtained from nutshells through activation with phosphoric acid and oxidized with H2O2 and later impregnated with salt containing Co2+, Ag+, Ni2+, Cu2+, has been investigated. The efficiency of ammonia ions and ammonium elimination from various water categories, using both activated carbon (the intact CAN-7 and CAN-7 oxidized with H2O2 and impregnated with Co2+, Ag+, Ni2+, Cu2+ ions) has been demonstrated.