Wastwater Treatment by Using Thermo-responsive Polymer

一种水溶性聚合物，聚(N-异丙基丙烯酰胺)，PNIPAAm，在较低的临界溶液温度(约32ﾟC)以上变得不溶于水，并形成具有非常小体积分数的胶状聚集体(聚合物相)。聚合物沉淀的特征取决于聚合物的摩尔质量和/或盐或缓冲成分的浓度。随着聚合物相的形成，水中的多环芳烃、烷基酚、氯苯、氯酚、邻苯二甲酸酯、农药和甾体激素等疏水有机化合物被有效地结合到聚合物相中。另一方面，亲水组分，如无机离子或多糖仍留在主体水溶液中。化合物的萃取率随疏水性能的增加而增加。基于其水相和聚合物相的体积分数的分配系数与水-辛醇分配系数和水-聚合物分配常数相关联。两个平衡系数之间的线性关系表明，疏水相互作用是溶质结合的主要作用力。聚合物介体萃取在废水处理中的应用将极大地拓展该方法在氯酚、农药等痕量环境污染物的预浓缩中的潜力。

A water-soluble polymer, poly(N-isopropylacrylamide), PNIPAAm, become waterinsoluble above a lower critical solution temperature(ca.32ﾟC) and forms gum-like aggregates (polymer phase) having very small volume fraction. The features in the polymer precipitation were dependent on the molec ular weight of the polymer and/or the concentration of salts or buffer components. Accompanying with the formation of the polymer phase, hydrophobic organic compounds including poly cyclic aromatic hydrocarbons, alkylphenols, chlorobenzens, chlorophenols, phthalic esters, pesticides and steroid hormones in water were efficiently incorporated into the polymer phase. On the other hand, hydrophilic components such as inorganic ions or polysaccharides remained in the bulk aqueous solution. The extractabilities of compounds increased with increasing the hydrophobic properties. The distribution coefficients, based on the volume fractions of their aqueous and polymer phases, were correlated with the aqueous-octanol distribution coefficients and aqueous-polymer distribution constants. Linear relationship between two equilibrium coefficients indicated that the hydrophobic interaction is predominating force for incorporating solutes. The application of the polymer-mediated extraction to wastwater treatment will greatly extend the potential of this method in the pre-concentration of traces of environmental pollutants such as chlorophenols, pesticides.