以甲苯二异氰酸酯为单体,在水和丙酮混合溶剂中不用致孔剂且无需任何高分子改性一步法合成了聚脲多孔材料(PPU),通过扫描电镜和BET氮气吸附法对其表面形貌和孔参数进行了表征.以酸品红(AF)溶液模拟染料废水,对其在PPU上的吸附进行了研究,讨论了pH、吸附时间、AF初始浓度及吸附剂用量对吸附过程的影响,优化了吸附条件.结果表明,PPU对染料AF具有优异的吸附效果.PPU在30℃,pH=3时对AF的最大吸附量为44.60 mg/g.PPU对AF的吸附过程更接近于Langmuir等温吸附的单分子层吸附机理.PPU对水溶性染料刚果红(CR)也有很好的吸附能力.使用水、乙醇和水混合溶剂以及NaOH水溶液对染料吸附后的解吸附结果表明,乙醇和水混合溶剂对吸附染料的解吸效率最高,对2种染料的解吸附都达90%以上.解吸后PPU的再吸附能力略有下降,但第三次吸附量仍达到首次吸附的80%以上.
A novel one-step protocol for facile preparation of porous polyurea material(PPU) through precipi- tation step polymerization of toluene diisocynate (TDI) as the sole monomer with water in water-acetone mixed solvent was presented, in which neither any porogen during the polymerization, nor chemical modification on the outcome polymer was need. The surface morphology and pore parameters of PPU as prepared were charac- terized by scanning electron microscope (SEM) and Brunauer-Emmett-Teller(BET) nitrogen adsorption, re- spectively. Presence of abundant amine groups on PPU surface was confirmed by infrared measurement. Using acid fuchsine (AF) in aqueous solution as an example for dyes in wastewaters, the effects of AF adsorption pH, adsorption time, AF concentration and amount of PPU on the adsorption process were studied. AF ad- sorption was more effective with pH located between 2----4; adsorption equilibrium was usually reached with4 h. AF was nearly full adsorbed at low concentration or with high PPU loading. The maximum adsorption capacity of AF on PPU was 44. 60 mg/g under optimized conditions. Analysis of the adsorption results demon- strated that the adsorption was better fit by Langmuir adsorption equation compared to Freundlich adsorption. In addition, Congo red(CR) was also used and its adsorption on PPU also studied. The maximal adsorption of CR on PPU was of 90. 48 mg/g. Desorption test demonstrated that over 92% of the adsorbed dye molecules on PPU were desorbed when PPU with adsorbed dyes was immersed into NaOH solution( 1 mol/L) or H2O/etha- nol mixture( 1 : 1, volume ratio) for 2 h. The following reuse of PPU demonstrated that dye adsorption was higher than 90% of the initial adsorption in the re-adsorption, and it was higher than 80% of the initial adsorption in the third adsorption. The results indicate that PPU is an effective absorbent to remove AF and CR in aqueous medium, and an attractive candidate for removal of anionic dyes from the wastewaters.