Phenolic Resin-based Membranes Preparation And Separation Performance

As a renewable resource, ethanol gasoline has been attracted much attention to the world. Ethanol gasoline, which is produced by biological ferment-distillation condensation, is still cost-effective due to much energy consumption of traditional distillation condensation. Pervaporation is considered as a prosperous separation process because of its simple operation, low energy consumption and environmentally low-emission.In this study, a thermosetting phenolic resin was synthesized by copolymerization of Resol-type phenolic prepolymer(PF) with sulfonated Novalak-type phenolic prepolymer(SPF), which is called sulfonated Resol-Novalak phenolic resin(PF/SPF). PF/SPF composite membranes were prepared by coating a thin film of PF/SPF on a porous alumina tubular support. The swelling degree of PF/SPF has been investigated in 50wt% ethanol solution. The results showed that the hydrophilicity of PF/SPF increased as the amount of PF increased. PF/SPF composite membranes with different ratio of PF and SPF have been studied in the pervaporation separation of ethanol/water mixtures. PF/SPF (7/3, by wt.) composite membrane has a total permeability of 180g·m^-2·h^-1 and a separation factorα_H20/E(?)0H of 65 at a composition of 90wt% ethanol and a feed temperature of 75°C.The effect of test conditions on separation performance and stability of PF/SPF composite membrane has been researched primarily.Carbon black, which was grafted by p-phenol sulfonic acid (p-PS), was used in the modification of PF/SPF composite membrane. After the oxidation of carbon black with hydrogen peroxide, hydrophilic group was introduced onto carbon black surface by the grafting reaction of carbon black with the active hydrogen of p-PS. The effect of the reaction time and the solvent on the grafting yield was investigated. The grafted carbon black was characterized by TEM and dispersing stability test. Hydrophilicity of carbon black was well improved by the modification of p-PS. The separation performance of PF/SPF composite membrane was enhanced by coating a thin film of PF/SPF on the surface of the pretreated tubular support, which was prepared by coating hydrophilic modified carbon black on the surface of a porous alumina tubular support. The modified PF/SPF composite membrane has a total permeability of 96g·m^-2·h^-1 and a separation factor α_H20/Es0H of 204 at a composition of 90wt% ethanol and a feed temperature of 75°C.In addition, PF/SPF-based carbon membranes were prepared. Gas separation equipment was assembled and adjusted. Gas separation performance of carbon membranes was measured. PF/SPF-based carbon membranes displayed CO₂/N₂,He/N₂ separation factors of 1.08 and 3.17 at 25°C and 0.1 MPa, which is barely more than those of correspondent Knudsen diffusion separation factors, 0.80 and 2.65 respectively, indicating that it's necessary to make a deeply study of polymeric precursor and carbon membrane preparation processes.