NOVELTY - Method of making treated carbon, comprises: providing a carbon sample; flowing a reactant gas over the carbon sample; heating the carbon sample to at least 300 degrees C; and targeting the carbon sample with microwave energy at or ambient pressure or greater.    USE - The method is useful in ultracapacitor or fuel cell electrodes, water purification (desalinization), recovery of precious metals (e.g. treat carbon for affinity to a particular ion, such as gold), and indication for adsorption properties.    ADVANTAGE - The functional group is reduced by more than 50% or 80%. The method can be performed at lower temperature and ambient pressure. The method: reduces initial rate of capacity loss; increases number of C=C bond formation; maintaining particle size, pore size, and pore volume for maintaining the available surface area for capacitance; and reduces oxygen containing functional groups. The method is: carried out quickly in a reaction chamber that does not require a vacuum making the reaction chamber; and cost effective, time saving, easy to perform and scaleable for production volumes.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a system for modifying carbon material at or ambient pressure or greater, comprising: a reaction chamber; a heating element configured to heat the chamber to more than 300 degrees C; a gas inlet configured to receive a gas flow and direct the gas flow to the chamber; and a microwave source;    (2) an electrochemical double layer capacitor comprising: a first electrode; a second electrode; a porous separator (16) disposed between the first and second electrode; a container; and an electrolyte, where the first and second electrode comprises treated carbon formed by the method; and    (3) a treated carbon with reduced oxygen-containing functional groups formed by the method.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-section of electrode assemblies.    Current collector (12, 20)    Active electrode film (14, 18)    Porous separator. (16)