Study On Preparation And Application Of Carbon/Ceramic Support Composite Membrane

As a new type of inorganic membrane material,carbon membrane has many excellent properties and it has good separation and stable chemical properties compared with organic membrane.While pure carbon membrane has relatively poor mechanical properties which would be necessary to select a suitable support to improve its mechanical strength and to develop a new composite carbon membrane based on maintaining its excellent separation performance.The commercial porous inorganic ceramic tube was used as a support.The composite carbon membrane was prepared by spray coating with different high molecular organic in this parper.Thermogravimetric?TG?,infrared spectroscopy?FT-IR?and SEM were used to characterize the composite carbon membrane.There were investigated the effects of different precursor materials and analyzed the mechanism of the composite interface on the composite carbon membrane.The optimization of process parameters were optimized for the preparation of composite carbon membrane and those composite carbon membranes were applied to the separation of coking wastewater.The results showed that:?1?Those precursor materials?cellulose acetate?CA?,coal tar?CT?,polyacrylonitrile?PAN?and thermoplastic phenolic resin?PFNR?+5wt.%hexamethylenetetramine?HMTA??were used to prepare the support carbon membrane through spraying the pretreated ceramic tubes.The carbon membrane still retained the original skeleton structure of the precursor material comparing FT-IR of the four coating materials before and after pyrolysis.There could be seen that the CA residual carbon rate after pyrolysis was only 3.46%,while CT,PAN,PFNR+5wt.%HMTA had higher residual carbon rate after pyrolysis at 900°C through TG curve.There were many defects of the support carbon membrane prepared by CA and PAN according to the SEM image.The more coating solution was infiltrated into the dense layer of the ceramic tube when the CT was used the precursor material to prepared support carbon membrane which resulted in serious change of the ceramic tube structure and unfavorable the preparation of support carbon membrane.However the surface of the composite carbon membrane prepared by PFNR+5 wt.%HMTA was smooth and flat which had a good structure and the average pore diameter about0.16?m.?2?The mechanism of interface bonding between the ceramic tube and the carbon membrane were mainly mechanical interlocking through inlaid and firmly combined with each other according to the SEM image analysis.Therefore the PFNR+5 wt.%HMTA was selected as the coating material for preparing the support carbon membrane.?3?Through the influence analysis of coating solution concentration,carbonization final temperature,carbonization time and the number of coating times on the composite carbon membrane,the optimization of the prepare parameters were coating solution with 30 wt.%PFNR+5 wt.%HMTA,carbonization final temperature at 850°C,time being 60 min,and two coatings,the thickness of composite carbon membrane was about 13?m and the average diameter was 0.09?m,which would be excellent structure performance.?4?Coking wastewater was treated by the composite carbon membrane,the wastewater flux under conditions around 1.52 L·m^-2·h^-1 and the COD removal rate of the wastewater could reach 52.96%when the static pressure was 0.5 MPa.The composite carbon membrane has good treatment capacity for coking wastewater.