A composite, clay supported carbon membrane has been synthesized by carbonization of a blend of polyethylene glycol and phenol formaldehyde resin and the membrane thus obtained is characterized by separation of dyes. This membrane is subjected to permeability test using pure water which is found to be considerably higher than that reported in literature. It is subsequently shown to reject Acid Orange 7 dye from water with the rejection dependent on pressure and concentration of the dye which is typical phenomenon observed for a charged membrane. The separation data has been analyzed using the Space charge model and the membrane charge is estimated by minimizing the root mean square error between the experimental results and those calculated from the model. (C) 2009 American Institute of Chemical Engineers AIChE J, 55: 1712-1722, 2009