into it the particles are in physical and electrical contact with an electrically conductive hydraulically permeable matrix 130 which is also embedded into the membrane sheet 120 the membrane sheet divides the anode compartment from the cathode compartment and limits the type and amount of fluids and or ions that pass between the anode compartment and the cathode compartments the membrane may be a single layer membrane or a composite layer membrane the membrane may be constructed of a fluorocarbon type material or of a hydrocarbon type material such membrane materials are well known in the art preferably however fluorocarbon materials are generally preferred because of their chemical stability non ionic thermoplastic forms of perfluorinated polymers described in the following patents are suitable for use in the present invention u s pat nos 3 282 875 3 909 378 4 025 405 4 065 366 4 116 888 4 123 336 4 126 588 4 151 052 4 176 215 4 178 218 4 192 725 4 209 635 4 212 713 4 251 333 4 270 996 4 329 435 4 330 654 4 337 137 4 337 211 4 340 680 4 357 218 4 358 412 4 358 545 4.