| Acetaminophen?APAP?is a common analgesic and anti-inflammatory which has the exact effect,few side effects and a huge demand in market.At present,the methods of dealing with APAP wastewater are mainly thermal concentrated,macroporous resin adsorption and photochemical catalysis which also have corresponding deficiencies.The APAP in aqueous solution was extracted by two methods:emulsion liquid membrane?ELM?and supported liquid membrane?SLM?.The good stability of the emulsion is a prerequisite for the effective extraction of APAP.The emulsion was prepared by the combination of low speed stirring and ultrasonic.The composition of emulsion and the emulsifying conditions were optimized.The effects of various factors on the stability of the emulsion were studied.The concentration of Span-80,TBP,liquid paraffin and NaOH was separately 6wt%,3wt%,2wt%and 0.1mol/L,the ratio of membrane to internal phase was 1:1 and the stability of the emulsion was good.The type of emulsion was W/O and the average diameter of emulsion droplet was 187.9nm.The APAP in aqueous solution was extracted by ELM system,under the conditions of Span-80 6wt%,liquid paraffin 3wt%,TBP 4wt%,NaOH 0.1mol/L,the ratio of membrane to internal phase was 1:1,the ratio of membrane to external phase was 1:4 and the stirring speed was 180rpm,the extraction ratio of APAP was 84.75%.Heating method,centrifugation and freezing thawing method were used to demulsification,the corresponding demulsification ratio in turn increased.After demulsification,the oil phase was reused 5 times and the extraction ratio was more than 75%.TBP was used as complexing agent to study the effect of different factors on complexation equilibrium.It was deduced that TBP and APAP formed a?2:1?complex by intermolecular hydrogen bonding and the reaction was exothermic.Based on the complexation extraction experiment,PVDF as support material,under the optimized extraction conditions,the permeation coefficient of APAP was 3.03×10-6m/s and diffusion coefficient in membrane phase of the TBP and APAP complexes was 1.041×10-10m2/s.Both the two liquid membrane methods can effectively extract APAP from aqueous solution.In the process of ELM,extraction time was much shorter and extraction ratio was much lager.In the process of SLM,the consumption of organic solution was much less.The mass transfer model was constructed in the process of SLM which can provide the theoretical guidance for industrial application. |
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