Optimal Preparation Of PDMS Pervaporation Membranes For Butanol Separation

Biobutanol,as a representative of biofuels,is an ideal renewable green energy source and can be used as a substitute for fossil fuels.However,the product inhibition problem in the fermentation broth seriously reduces the efficiency of bio-butanol production.Pervaporation technology can directly separate butanol from fermentation broth by in-situ separation,reducing product inhibition and separation energy consumption.It is an efficient,green,and biocompatible separation process.Polydimethylsiloxane（PDMS）membranes are considered the‘benchmark for alcohol-selective membranes’due to their excellent hydrophobicity,stability,and pervaporation performance.Mixing inorganic particles as fillers with PDMS matrix to prepare Mixed Matrix Membranes can yield better performance butanol separation pervaporation membranes.On the other hand,PDMS membrane has some problems in the process of industrial preparation,such as slow curing,unstable performance and low separation factor.Therefore,in this paper,MAF-9/PDMS hybrid matrix membrane was prepared to obtain better butanol separation effect,and V-PDMS membrane that can be cured quickly was developed to realize the industrial preparation of PDMS membrane.The research in this paper includes the following contents:Firstly,an ultra-hydrophobic metal organic framework MAF-9was synthesized and mixed with the PDMS matrix to prepare MAF-9/PDMS mixed matrix membranes.The results shown that the synthesized MAF-9 has extremely high hydrophobicity due to the presence of the-CF₃group in the ligand,with a water contact angle of 146.5°.Membranes filled with 6 wt%MAF-9 have the best performance,with a total flux of 848 g m^-2h^-1and separation factor of 53,which are 24%and 16%higher than pure PDMS membrane,respectively.In addition,the separation effect of 6%-MAF-9/PDMS mixed matrix membrane on fermentation broth was tested,demonstrating its potential for in situ butanol separation.Secondly,in order to solve the problems encountered in the industrial preparation of PDMS membranes,V-PDMS membranes were prepared using the method of hydrosilylation and thermal solidification.The casting solution of this membrane can be stored for more than 4 hours at room temperature,while it only takes 5minutes to quickly solidify at 80℃.Therefore,large-scale continuous membrane preparation equipment can be used for continuous production of this membrane,greatly improving the production efficiency of PDMS pervaporation membrane.At the same time,the membrane also has excellent butanol separation performance.The V-PDMS membrane prepared in the laboratory has a total flux of 1384 g m^-2h^-1and a separation factor of 42,which is superior to other PDMS membranes and commercial membranes reported in the literatures,and therefore has high economic value.