In this work, poly(styrenesulfonate) membranes were produced through the sulfonation of wasted polystyrene plastic cups. The produced membranes presented good workability and ion exchange capacity of 1.3 +/- 0.1 meq/g. The sulfonated membranes showed significantly increase in the water sorption, what is relevant in industry since most of the processes of separation deal with the presence of ions which means of transport is the water. The membrane of sulfonated polystyrene plastic cups (PSSwastecups) was compared with the sulfonated membrane of virgin resin (PSSstandard). The viscosimetric molar weight of PSSstandard was higher than PSSwastecups how indicated by difference between intrinsic viscosity. This fact influences the production of the membrane and consequently the transport property. The PSSwastecups absorbs a higher amount of water than the PSSstandard, what is due to the presence of less macromolecule chain coils, producing low-density regions where clusters may be formed. This diminishes the diffusion coefficient and increases the water sorption in the PSSwastecups membrane.