液膜法提取废水中的扑热息痛
Paracetamol Recovery from Wastewater Using Emulsion Liquid Membranes

利用搅拌-超声技术制备乳化液膜, 以提取制药废水中的扑热息痛．采用冷冻-解冻技术进行破乳．设计单因素实验方法来研究不同实验条件对扑热息痛提取率的影响, 并考察了破乳率与冷冻时间的关系．得到最佳实验条件为：膜溶剂煤油、三辛胺、Span-80质量分数分别为84% 、5% 、8% , 内相 NaOH 质量分数为0.4% , 油内比Roi为1(体积比), 乳水比Rew为1/4(体积比), 外相初始pH值为4～5, 搅拌转速250 r/min．在该条件下, 当扑热息痛初始质量浓度ρ0＝200 mg/L时, 传质50 min, 提取率为92.47% ．-20～-25 ℃冷冻24 h, 破乳率为69.42% ．油相经5次利用后, 提取率依然不低于82.34% ．此外, 总包传质系数D随ρ0的增大而线性增加．
An emulsion liquid membrane was prepared by stirring/ultrasound technology to recover paracetamol from pharmaceutical wastewater. A freeze-thaw method was applied to separate the oil and internal phases. The effect of operating conditions on the paracetamol extraction rate was investigated through a single-factor experiment and the relationship between the demulsification ratio and freezing time was discussed. The optimal experimental conditions are as follows: kerosene is selected as the membrane solvent，and the mass fractions of kerosene，trioctylamine and Span-80 are 84%，5% and 8%，respectively; the NaOH mass fraction is 0.4% ; the Roi(volume ratio of oil to internal phases)is 1 and Rew(volume ratio of emulsion to external phases)is 1/4; the initial pH value of the external phase fluctuates between 4 and 5; and the most suitable stirring speed is 250 r/min. Under these optimal conditions，when the initial paracetamol mass concentration ρ0 is 200 mg/L，the extraction efficiency reaches 92.47% after 50 min of operational time. The demulsification ratio can be up to 69.42% after the emulsion was frozen for 24 h at -20～-25 ℃. Meanwhile，the paracetamol extraction efficiency is not lower than 82.34% even after the oil phase was reused five times. In addition，the overall mass transfer coefficient D increases linearly with the increase of ρ0