Study On A Novel Hydrophilic Ceramic-supported Polymer Composite Membrane:Preparation And Pervaporation Properties In The Dehydration Of Organic Solvents

The dehydration of organic solvents by pervaporation through membrane is attracting increasing interest in industry. Most pervaporation studies have involved hydrophilic polymer membranes with high selectivities, but there are drawbacks which include lack of physical and chemical stability. Ceramic membranes are known to have high mechanical and thermal stabilities and a good stability towards organic solvents. However, the ceramic membranes have poor selectivity for its limited selection of pore size. In this paper, a novel hybrid membranes which blend ceramic and polymeric membrane properties have been synthesized.In this paper, the microporous amorphous SiO₂ membrane was prepared on cordierite support by low temperature chemical vapor deposition(LTCVD) and Sol-gel methods,respectively. Surface modification of the support SiO₂ membrane was performed in two steps: surface activation and graft polymerization. A novel hydrophilic ceramic-supported polymer composite membrane was prepared by graft-polymerization of acrylamide or acrylic acid on a microporous silica membrane, which was silylated by γ-(methyl acryloyl) propyl tri-methoxysilane. In order to establish the operating conditions for the considered grafting, Surrogate silica particles and silicon wafer was used as the substrate on which AA or AM was graft polymerized under the same conditions as the ceramic-supported polymer composite membrane. The silylation and graft yield were determined by TGA ,the morphology of the membrane have been analyzed by SEM, AFM , Film thickness of the polymer grafted silicon wafer was measured with ellipsometer, Contact angles for water and hexadecane on the composite membranes were studied. The element composition of the composite membrane was characterized by XPS. It proved that the polymer chains had been successfully grafted on silica membrane, The active ultrathin PAA or PAM separation layers consisted of terminally anchored polymer chains. The graft yield were proportional to the initial monomer concentration, we found that the higher monomer concentration,the higher membrane thickness, the higher selectivity and lower flux. This membrane type is particularly attractive because a wide variety of monomers can be used in the graft polymerization reaction, thereby we can design such membrane for different pervaporation applications. The ceramic-supported polymer composite membrane had been tested in a pervaporation device for dehydration of several other organic solvents. The results showed that the...