“珊瑚”状PAD的合成及絮凝性研究

STUDY ON THE SYNTHESIS AND FLOCCULATION PERFORMANCE OF CORAL-SHAPED OF PAD

采用"先核后臂"法,以丙烯酰胺、丙烯酰氧乙基三甲基氯化铵、正硅酸乙酯为原料,季戊四醇为支化剂,硝酸铈铵作引发剂,通过自由基聚合反应和原位聚合反应合成了超支化阳离子聚丙烯酰(PAD)。通过FT-IR、~1H NMR对其结构进行了表征,扫描电镜对其表面微观形貌进行观察与分析。考察了投加量对硅藻土模拟废水上清液透过率和沉降时间的影响,并测定了颗粒平均粒径、Zeta电位、分形维数和絮体的微观形貌,对絮凝性能和絮凝机理进行了研究。结果表明:PAD的投加量为8mg时,透过率达98.49%,絮凝时间仅为10s,Zeta电位为0.273mV,颗粒平均粒径为572μm,絮凝后的絮体体积较大、分布密集,起到了良好的电性中和和吸附架桥效果,具有良好的絮凝性能。

Hyper-branched cationic polyacrylamide（PAD）was synthesized with free radical poly-merization and in-situ polymerization through core-first method using acrylamide,acryloxyethyl trimethyl ammonium chloride,tetraethoxysilane as the raw materials,pentaerythritol as branched agent,cerium ammonium nitrate as initiator.The structure was characterized by IR,^1H NMR,the surface morphology was observed and analyzed by scanning electron microscope.The effects of various factors on the transmittance and flocculation settling time of the supernatant of simulated diatomite waste-water were investigated Zeta potential,average particle size,fractal dimension and the surface micro-morphology of floc before and after flocculation were determined,and the flocculating performance and flocculation mechanism were also studied.The results showed that it has good electric neutralization and adsorption bridge effect,and has good flocculation performance when the dosage is 8 mg,the transmittance is up to 98.49% and the settling time is only 10 s,the Zeta potential is -0.273 mV,the average particle size of the particles is 572μm and the morphology and size of flocs are larger and densely distributed in the after flocculation.