Preparation and Formation Mechanism of Porous Polyurea by Reaction of Toluene Diisocyanate with Water and Its Application as Adsorbent for Anionic Dye Removal

A novel and easy one-step protocol for preparation of a new porous material, polyurea （PPU）, is reported, which is accomplished through a precipitation polymerization of toluene diisocyanate （TDI） in mixed solvent of H20-acetone without need for surfactant and porogen. Effects of TDI concentration, mechanical stirring, solvent composition and TDI addition rate on PPU structure are studied. Surface morphology and pore structure of PPU are characterized by scanning electron microscopy and Hg intrusion. Chemical structure of the PPU polymer is investigated using NMR, XRD and FTIR. Mechanism of pore formation is discussed. The obtained PPU is used as adsorbent for anionic dyes adsorption investigation. Two anionic dyes, remazol brilliant blue R and acid fuchsine, are tested. The results indicate that the as-prepared PPU is of high performance in dye adsorption and recycled use. This study provided therefore a facile route to the preparation of a novel and attractive adsorbent candidate for removal of anionic dyes from wastewaters.