Water Purification from Organic Pollutants by Water-Filled Nanoporous-Crystalline Polymer Films

Water-filled films of a hydrophobic thermoplastic commercial polymer are obtained, without recourse to hydrophilic chemical functionalization of the polymer. The proposed procedure is effective for high surface area (HSA) polymer films, which can be obtained by fast cocrystallization of amorphous films, as induced by high uptakes of nonvolatile low molecular mass guest molecules. This study refers to HSA nanoporous crystalline (NC) polyphenyleneoxide (PPO) films with a water-filling procedure including two consecutive steps: sorption of ethanol and ethanol exchange with water. The reported sorption data clearly indicate that the uptake of the organic pollutant is mainly by the intrahelical crystalline channels of the NC phase, while the sorption kinetics mainly depend on the film surface area and are particularly fast after water filling of the polymer film. Water-filled HSA NC PPO films are much more effective than any other polymer film for the sorption of organic pollutants from dilute aqueous solutions, as also shown by comparison with a commercial benchmark adsorbent polymer. These adsorbent polymers could be relevant for purification processes of drinking water (from traces of disinfection byproducts or of persistent chemicals) and as concentrators of organic pollutants from aqueous solutions, for analytical purposes.