Pervaporation Behavior Of Polyether Block Amide(PEBAX)Composite Membranes For The Removal Of Pyridine

The storage performance and usability of gasoline and the natural environment of the world have been greatly influenced by nitrogenous compounds contained in gasoline.Pervaporation has gained more and more attention as a new technology of membrane separation in the petroleum refining industry.In this study,polyacrylonitrile(PAN)ultrafiltration membrane has been chosen as supporting layer,and polyether block amide(PEBAX)as separation membrane material.CTAB-modified bentonite and hydrophobic Nano-fumed silica(n-SiO2)were used as filling agents.Composite membrane and two kinds of filled composite membrane were prepared respectively.The aim is separation of pyridine by pervaporation.In order to identify the filling situation of particle in polymer and observe the microstructure of membrane,FTIR,XRD and SEM characterizations were conducted.The FTIR and XRD results indicate that modified bentonite and n-SiO2 are both physically blended with the polymer.The SEM result shows that the membrane is dense and nonporous,combination of the separation layer and the support layer is well.Swelling property and pervaporation performance of membranes were explored in model gasoline composed of pyridine and n-heptane.The swelling adsorption experiment shows that the swelling degree of membrane increases with the increasing pyridine concentration and feed temperature,which indicates that the membrane have a preferential adsorption selectivity to pyridine.The pervaporation results show that both the separation factor and total flux increase,when the pyridine concentration in feed increase.The increase of feed temperature enhances the total permeation flux but weakens the separation factor.Compared to composite membrane,total permeation flux and separation factor of the two filled composite membrane have been improved.When the filling amount of CTAB modified bentonite and n-SiO2 were 15wt.%and 5wt.‰ respectively,their pervaporation performance were the best among all filling amount.When pyridine concentration was 5000 ?g·g-1 and feed temperature was 30?,separation factor and total flux of PEBAX/PAN composite membrane were 2.45 and 4.14 kg-m-2·h-1,the membrane filled with 15 wt.%modified bentonite were 2.62 and 5.15 kg-m-2-h-1 respectively,and the membrane filled with 5 wt.‰n-SiO2 were 3.39 and 5.05 kg·m-2-h-1 at the same condition.In summary,for the removal of pyridine via pervaporation,separation performance of the two filled composite membranes was better than composite membrane.The n-SiO2 filled composite membrane has better separation performance than modified bentonite-filled composite membrane.