Development of Material for Chemical Separation using Hydrophobic Surface of Recycled Polyvinylchloride

(1)研究了含苯酚及其衍生物的芳香族化合物与农用回收聚氯乙烯（RPVC）混合后在水中的分布行为。发现分布以苯酚<对甲酚<对乙基苯酚<对丙基苯酚<对丁基苯酚的顺序增加。为了了解增塑剂在RPVC中的作用，测定了这些芳香族化合物在邻苯二甲酸二（2-乙基己基）酯和水之间的分配系数，发现溶质的疏水性对分配起重要作用。与增塑剂相比，PVC树脂对这些化合物的吸附相对较小。因此，水中的疏水性物质被萃取到RPVC中的增塑剂中。(2)用三辛基甲基氯化铵（TOMAC）的50% THF-H_2 O溶液与硬质聚氯乙烯（RPVC）混合，对RPVC进行表面包覆。采用苦味酸离子对萃取法测定水溶液中的TOMAC。这些结果表明，相当数量的TOMAC可溶于水。但加入NaCl、KNO_3、HCl等电解质后，溶解度降低。(3)研究了金（III）、铂（IV）和钯（II）在1 M-HCl介质中在RPVC负载TOMAC上的分配行为。发现分布速率如下降低：Au（III）>Pt（IV）>Pd（II）。与贵金属离子相比，金属离子如Zn（II）、Cu（II）和Fe（III）的分配比小。研究了用0.1M硫脲溶液洗脱RPVC中吸附的贵金属离子。Au（III）的回收率在80%左右。在相同条件下，Pd（II）和Pt（IV）的回收率分别约为40%和10%。

(1) Distribution behaviors of aromatic compounds containing phenol and its derivatives in water were investigated by mixing recycled polyvinylchloride (RPVC) from agricultural use. The distribution was found to increase in the order phenol<p-cresol<p-ethylphenol<p-propylphenol<p-buthylphenol. To find out the role of the plasticizer in the RPVC, the distribution coefficients of these aromatic compounds between di-2-ethylhexyl phthalate and water were determined to reveal that the hydorophobicity of the solute played important role for the distribution. The adsorption of PVC resin of these compounds was relatively small compared to the plasticizer. In conclusion, the hydrophobic substances in water were extracted to the plasticizer in the RPVC.(2) The surface of the RPVC was coated with trioctylmethylammonium chloride (TOMAC) by mixing its 50% THF-H_2O solution with RPVC. The TOMAC in water solution was estimated by ion-pair extraction method with picric acid. These results show that a considerable amount of TOMAC is soluble in water. But the solubility was depressed by the addition of such an electrolyte substance as NaCl, KNO_3 and HCl.(3) The distribution behaviors of gold (III), platinum (IV) and palladium (II) in 1M-HCl to RPVC loaded TOMAC were investigated. The rate of distribution was found to decrease as follows ; Au (III)>Pt(IV) >Pd(II). The distribution ratio of the metal ions such as Zn(II), Cu (II) and Fe (III) was small compared to that of precious metal ions. Elution of the adsorbed precious metal ions from RPVC was investigated using 0.1M thiourea solution. The recovery of Au ((III) was about 80%. On the other hand, the recoveries of Pd (II) and Pt (IV) were about 40% and 10% respectively under the same condition.