Pervaporation Separation Of Ethanol / Water And Mass Transfer Mechanism

In this paper, the Chitosan was used as the raw material. To prepare the CS homogeneous membrane, CSA/PAN composite membrane and CS-PVA/PAN blending composite membrane. The experiments of swelling and pervaporation (PV) were carried out with ethanol and water being experimental system. The effects of deacetytation , condition of membrane preparation, feed temperature and composition, membrane thickness , blending ratio on pervaporation were discussed . The results showed that the pervaporation properties of three kinds of membranes were good. The production ability of CSA/PAN composite membrane was much higher when ethanol in feed was 50%,temperature was 333.15K. Productivity of CSA/PAN composite membrane was 83.01 kg/m2h. The separation factor of CS-PVA/PAN composite membrane was much higher, even reaching the crest 8 and the ethanol can be condensed to 99.7%.The separation performance of CS homogeneous membrane mainly depends on solution and sorption equilibrium at the membrane interface . The transporting mechanism of CS homogeneous membrane was studied. According to solution-diffusion theory, Fick law and Flory-Huggins theory ,the mathematical model considering "coupling effect" of CS homogeneous membrane was established . The calculating results of mathematical model were in agreement with the experimental results .The experimental data was correlated and the correlation formulas of transporting water and ethanol in CSA/PAN composite membrane were established respectively, that is, Jw=111.983-6.2334Ce; Je=2.3998-0.133107Ce. Theoretical predictions agreed well with the experimental results .