APPLICATION OF CLAYS TO REMOVAL OF RED TIDE ORGANISMS I. COAGULATION OF RED TIDE ORGANISMS WITH CLAYS

Coagulation of red tide organism cells with clays is discussed in theory and the effects of some factors on it are studied. A quantitative model is presented which describes how the coagulation varies with pH in solution. According to the model, within the pH-range between pHzpcb, and pHzpcb, VR is negative and the coagulation is strong and strongest at pH = (pHzpca + pHzpcb)/2. It is also demonstrated that when the diameter of clay particles is close to that of cells, the collision probability is low, resulting in weaker coagulation. The model results have been corroborated by experiments and so are scientific and theoretical bases for application.

粘土-MMH体系对赤潮生物的絮凝作用机制研究

根据粘土表面改性对其絮凝作用影响的理论模型，提出在粘土中引入 ＭＭＨ（混合 金属层状氢氧化物正电胶体）的改性方法；考察了ＭＭＨ浓度及ＰＨ值对絮凝作用的影响。 结果表明，粘土中引入ＭＭＨ后，显著提高了对赤潮异弯藻（Ｈｅｔｅｒｏｓｉｇｍａ ａｋａｓｈｉｗｏ）和新月菱形 藻（Ｎｉｔｚｃｈｉａ ｃｌｏｓｔｅｒｉｕｍ）的去除效率，二者的适宜配比为ＭＭＨ：粘土＝０．１ｇ：１ｇ。在此基础上， 进一步研究了ＭＭＨ促进粘土絮凝作用的机制，发现其去除赤潮生物的效率与改性后表面 电性呈正相关，相关系数Ｒ＝０．９３，与以前提出的理论模型一致。

粘土-MMH体系絮凝赤潮生物的动力学研究

根据分子碰撞理论和粘土表面改性对絮凝作用的影响 ,进行了粘土 -MMH体系絮凝沉降赤潮异弯藻 (Heterosigmaakashiwo针胞藻 )和新月菱形藻 (Nitzschiaclosterium硅藻 )的动力学研究。在粘土中加入第二组分MMH(混合金属层状氢氧化物正电溶胶 ) ,改变粘土表面电性 ,并对上述两种藻进行絮凝动力学实验。结果表明 ,一定颗粒度的粘土对赤潮异弯藻和新月菱形藻的絮凝速率随体系中MMH比例的增大而呈不同程度的提高 ;对于粘土 /MMH比一定的混合体系 ,絮凝速率随粘土浓度的增大而逐渐提高 ;另外还考察了pH对粘土 -MMH体系絮凝赤潮生物的影响。从理论上分析讨论了以上各种因素的影响原因 ,证明在粘土表面引入MMH组分是一种有效提高赤潮生物絮凝速率的途径。