【摘要】 <正> 聚丙烯酰胺是最常用的水溶性高分子絮凝剂之一.广泛用于污水处理、选矿、钻井泥浆等方面,因此对它的絮凝机理的研究,有比较重要的价值.关于高分子絮凝机理比较成熟的有二:(1)高聚物的桥联作用.(2)高聚物的电荷中和作用.前者研究得比较透彻,特别是絮凝剂的分子量对絮凝影响的研究是比较成功的;而第二种说法在实际使用中常常有矛盾.在自然界,大部分胶体分散体系是带负电的,而合成高分子絮凝剂也大多是阴离子型的,可是后者对于前者却有很好的絮凝作用.所以有人认为凡是能克服库伦斥力的力都可以产生絮凝作用,因此阴离子型的絮凝剂能絮凝带负电荷颗粒是个普遍现象。更多还原

【Abstract】 Polyacrylamide possesses good flocculating action on the suspension of ontmorillonite. While the anionio type hydrolyzed polyacrylamides obtained from the partial ydrolysis of polyacrylamide show no flocculating action towards sodium-type montmorillonite, evertheless they have good flocculating action upon the calciumtype montmorillonite. It is ound in our experiments that the stronger flocculating action, generally the greater dsorption apacity, hence the principal condition to achieve flocculation must be that the polymer is ble o be adsorbed on the clay surface. However both hydrolyzed polyacrylamide and clay particles re negatively charged, thus it is impossible for them to approach each other, so that the locculating condition is absent. If there are Ca^II ions present in the solution, according o Sommerauer’s viewpoint, the sodium carboxylate groups of the hydrolyzed polyaorylamide shall orm —COOCa⁺ groups screening the negative charges of hydrolyzed polyacrylamide to allow the locculating agent to approach the clay particles. The adsorption capaoity is also somewhat ncreased, leading to flocculating action. The amount of Ca^II required depends on the degree f hydrolysis——i. e. the ratio of sodium carboxylate groups. By addition of appropriate uantities of sodium and calcium salts, the flocculating aotion of polyacrylamide to the uspension of montmorillonite can be controlled.更多还原