Recently, Egypt has suffered a sharp shortage of water for different uses. This fact could be aggravated in the very near future. Therefore, the need to valorize the non-conventional water resources is of vital importance. The current study aims to prepare a floating membrane using polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC) polymer, and copper oxide (CuO) for water desalination. The possibility of using the resulting membrane for distillation of the water with brine made using sodium chloride salt was tested. The prepared floating membrane was found to be effective in desalinating water. In addition, CMC/PVA- based composites have been electrically investigated to determine the low delay characteristics of high-frequency signal transmission. The permittivity and loss tangent of these composites were examined over a wide frequency range (10-1-106 Hz) at room temperature, using a broadband dielectric spectrometer (BDS). Experimental results reported low permittivity (~4 to 5) and loss tangent (~1×10-3 to 1.5×10-3) values. These features would make the composites promising in the high-frequency applications and desalination of saline water.