A novel and simple pathway to synthesis of porous polyurea absorbent and its tests on dye adsorption and desorption

A novel one-step protocol for the preparation of porous polyurea material （PPU） through precipitation polymerization of toluene diisocynate （TDI） is presented. The process is based on step polymerization of one single monomer, TDI, with water in water-acetone mixed solvent. PPU is obtained without need for any porogen or additives, and no any chemical modification on the outcome polymer is necessary. The morphology, pore size and size distribution of PPU are characterized by scanning electron microscope and BET nitrogen adsorption. Taking acid fuchsine （AF） and Congo Red as dye examples in wastewaters, their adsorption on, desorption from PPU and the reusability of PPU were tested. Experimental conditions for AF adsorption were optimized with regard to pH, adsorption time, AF concentration and amount of PPU. Results demonstrate that the as-prepared PPU is of high performance in dyes adsorption and recycled use. This work presents therefore a novel and attractive candidate for removal of anionic dyes from wastewaters.