磷酸三丁酯络合萃取邻氨基苯酚及工业废水预处理研究

Reactive extraction of o-aminophenol with TBP-solvent mixtures

根据络合萃取的原理，考虑了萃取剂与稀释剂之间的作用，选择磷酸三丁酯（TBP）为萃取剂．以正辛醇和氯仿为极性稀释剂、四氯化碳和煤油为非极性稀释剂，对邻氨基苯酚（OAP）稀溶液进行了探讨，讨论了体系的pH、TBP的浓度、稀释剂种类对萃取分配比（D）的影响。结果表明，TBP主要通过与OAP的中性分子键合作用实现萃取；D值的变化与中性分子的摩尔分数有关，pH是影响D的主要因素；稀释剂的极性对OAP的萃取影响较大，在萃取剂体积分数为10％～30％时，其萃取能力为TBP-正辛醇〉TBP-煤油〉TBP-四氯化碳〉TBP-氯仿；在萃取剂体积分数为30％～50％时，萃取能力为TBP-煤油＞TBP正辛醇〉TBP-四氯化碳〉TBP-氯仿。进而以30％TBP-煤油为萃取剂，对工业含OAP废水进行了错流萃取实验。实验表明，该方法可以对工业OAP废水进行有效的（94．7％）预处理；工业废水中的甲醇、乙醇，对萃取有较大影响。

Experimental runs of reactive extraction, with TBP-solvent mixtures employed as the extraction agent, were performed to remove o-aminophenol （OAP） from solutions and an industrial wastewater. Neutral OAP molecules were hydrogen bonded to TBP of the TBP-solvent extraction agent and removed with the organic phase. The extraction was most effective at a pH of 6-8, in the middle of pKα1 （4.74） and pKα2 （9.96）, where neutral OAP was predominant. The extraction effectiveness was also dependent on the solvent type and TBP concentration. When TBP accounted for 1%-30% by volume of the extraction agent, the order of declining extraction effectiveness was TBP-l-oetanol, TBP-kerosene, TBP-CCl4, and TBP-CHCl3, however, at a higher TBP concentration （30 % -50 % ）, the order was TBP-kerosene, TBP-l-oetanol, TBP-CCL, and TBP-CHCla. Therefore, TBP （30%）-kerosene was employed for removing OAP from a wastewater （OAP=13 245 mg/L） by cross flow extraction. Although the wastewater sample also contained high concentrations of methanol and ethanol, which were found to reduce the ex- traction effectiveness of TBP-kerosene, a very high OAP removal rate of 94.70% was achieved. The excellent result has demonstrated that the reactive extraction with TBP-kerosene is a viable pretreatment step for an industrial wastewater containing a high concentration of OAP.