Treatment Of High Acetic Acid Containing Wastewater With Microemulsion Liquid Membrane

With the increasing improvement of environment consciousness, environment protection has already been concerned to be a great problem by the whole society. The treatment of the high acetic acid containing wastewater is a difficult problem in environmental protection for the chemical and pharmaceutical industry. In this paper, the processing technology of the high acetic acid containing wastewater generated in the production process of pharmacy has been studied. By analyzing the relevant literatures and comparing the various processing methods, microemulsion liquid membrane technology was explored to treat this wastewater.Micoremulsion liquid membrane system which is applied to treat the acetic acid containing wastewater has been prepared. Suitable components of micoremulsion liquid membrane system were selected by experiments, the results are as follows: the surfactant is AEO-5 and AEO-7 remixed by the mass ratio 1:1, the cosurfactant is isopentanol and the membrane solvent is aviation kerosene. Then the formula of microemulsion liquid membrane which is used to treat the acetic acid containing wastewater was obained as follows: the membrane solvent: surfactant: cosurfactant: inner water phase is 38.9:23.3:15.6: 22.2(w/w).The reasonability of the microemulsion liquid membrane formula was verified by the study of thermodynamic behavior. The interfacial tension of each microemulsion liquid membrane was investigated to compare the effect of different surfactant, cosurfactant, membrane solvent and inner water phase on the interfacial property of microemulsion liquid membrane. The results farther verified the rationality of the microemulsion formula. The–△Gθo→i, -△Hθo→i and△Sθo→i were also obtained by experiment and calculation, and the stability of the microemulsion liquid membrane prepared in this study was further analyzed by these results.The mass transfer mechanism and the optimum technological conditions were obtained by doing experiments which is to treat acetic acid containing wastewater by microemulsion liquid membrane gotten above. The affecting factors which affect the removal of CODcr have been studied and the optimum technological conditions were obtained as follows: the Rew is 1:6, the concentration of NaOH in inter water phase is 3mol/L, the contact time is lOmin, the stirring speed is 200r/min. Under certain experiment condition, the removal rate of CODcr is more than 99.5%.The mass transfer dynamics of extracting acetic acid from acetic acid containing wastewater was studied. The transfer rate equation was obtained and verified in this research, and also the speed control type of treating the acetic acid containing wastewater was determined. The constants were gotten by doing experiments and the transfer rate equation was then obtained as follows: J=0.5158×Cw1.034.CNaOH0.472×10-5 .Compared with the results gotten from experiment and calculation, they were approximately accordant. The reaction activation energy was also abained as Eo—6.176KJ/mol by doing experiments, and the speed control type of treating the acetic acid containing wastewater was determined as diffusion-controlled by this result.