Innovative porous sulfonated poly(2,6-dimethyl-1,4-phenylene)oxide nanoporous crystalline films: A novel adsorbent to remove cationic dyes from wastewater

Sulfonated Poly(phenylene oxide) (sPPO) films with both macroporous hydrophilic sulfonated amorphous phase and hydrophobic nanoporous crystalline (NC) α phase were prepared by solid-state sulfonation and widely characterized. These semicrystalline porous sPPO films exhibiting both macro and microporosity were tested as a novel adsorbent for the adsorption of one of the most common cationic dye, the crystal violet (CV), from wastewater. Nanoporous crystalline sulfonated PPO (NC-sPPO) films evidenced a removal of CV definitively higher, close to 99 %, than the amorphous sulfonated film (R=25 %) and the NC un-sulfonated film (R=10 %). The adsorption kinetic was well explained through a second order model and, according to Langmuir model, a qm = 141 mg/g was obtained. The selective removal of NC sPPO films toward a cationic dyes mixture, made of CV, methylene blue (MB) and rhodamine B (RhB) molecules was also performed, showing an almost complete removal of all components of the mixture in a few hours. Reusability of NC sPPO films was also studied, obtaining a removal efficiency of 97 % after four cycles of film regeneration.