仲辛醇与仲辛酮萃取苯酚稀溶液性能研究

摘要

为了给工业含酚废水处理提供萃取剂选择和过程设计的指导,以中性含氧类萃取剂仲辛醇、仲辛酮为溶剂进行了苯酚稀溶液萃取性能的实验研究,测定了不同水相pH值、苯酚初始质量浓度条件下2种溶剂的萃取平衡分配系数,并研究了混合溶剂的萃取性能以及盐效应对于萃取平衡的影响.结果表明:在酸性和中性条件下,仲辛醇和仲辛酮对苯酚均有良好的萃取能力,仲辛酮优于仲辛醇；在碱性条件下,由于苯酚分子的解离,萃取平衡分配系数迅速下降.混合溶剂对苯酚的萃取有一定协萃效应,其机理与混合溶剂改变了溶剂分子间以及溶剂与溶质分子间的作用力有关.盐析剂NaSO4,NaCl的存在能够增强中性萃取剂对苯酚的萃取效果,通过实验数据的回归获得了该体系中盐析效应的表达式.%Experiments were carried out to provide guidance for industrial phenolic wastewater treatment. Distribution coefficient data were presented for phenol in its dilute solution at ambient temperature with physical extraction solvents 2-octanol and 2-octanone. The effects of pH values and the initial phenol mass concentration on the extraction equilibrium were studied. The results show that both solvents perform well in the acid solution and neutral solution, while 2-octanone has better performance than 2-octanol; in the alkaline solution, the distribution coefficient declines sharply because of the dissociation of phenol molecule to ions. The extraction with mixed solvent of 2-octanol and 2-octanone shows the synergistic effect, of which the mechanism is related to the interaction between the molecules of solvents, molecules of solvents and solutes caused by the mixed solvent. Salting-out effect of Na2SO4 and NaCl can enhance the extraction of phenol with 2-octanol, 2-octanone and TBP/kerosene respectively. The results of salting-out effect were correlated empirically with a good deviation. The synergistic effect and the salting-out effect can be applied to intensify the extraction process.