The effect of chemical treatment on the capacitance of carbon electrodes prepared from waste coffee grounds was investigated. Coffee grounds were impregnated with FeCl3 and MgCl2 and then treated at 900 degrees C. The resultant carbons were compared with activated coffee ground carbons prepared by ZnCl2 treatment. The carbon treatment processes of FeCl3 and MgCl2 were studied using thermal gravimetric analysis. Raman spectroscopy, x-ray photoelectron spectroscopy, and N-2 and CO2 adsorption were used to characterize the activated carbons. Activation with ZnCl2 and FeCl3 produced carbons with higher surface areas (977 and 846 m(2)/g, respectively) than treatment with MgCl2 (123 m(2)/g). Electrochemical double-layer capacitances of the carbons were evaluated in 1 M H2SO4 using two-electrode cells. The system with FeCl3-treated carbon electrodes provided a specific cell capacitance of 57 F/g.