Molecular nanocapsule-decorated porous monolith: preparation and elimination of cationic dyes from water

Abstract

To deal with cationic organic micropollutants in water, a macroscopic and porous adsorbent with the surface decorated with negatively charged molecular nanocapsules is described. The molecular nanocapsule is obtained by transforming hydroxyls of hyperbranched polyglycerol (PG) into carboxyls, and some of the carboxyls are capped by polystyrene–NH₂ (PS–NH₂) to form a hydrophobic shell. The successful synthesis of PS–NH₂ is supported by matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) spectra. The dendritic amphiphile of PG–COOH@PS can self-assemble along a water/oil interface to form a high internal phase emulsion (HIPE), where the continuous oil phase is styrene/divinyl benzene (St/DVB) and the dispersed phase is small water droplets, with oil/water = 20/80 (weight ratio). Polymerization of the oil phase and removal of the water droplets leads to an open-cellular material termed polyHIPE. The polyHIPE is characterized by an open-cellular porous structure and the surface-attached dendritic amphiphiles, and can eliminate cationic organic dyes from water.