Research On PDMS Pervaporation Membrane Modification And Pervaporation Performance

Pervaporation is a new development on membrane separation technology. It has many advantages, such as high efficiency, good security, no introduction of other chemicals, compact system and equipments, cheaper maintenance, and easy system scale-up. Pervaporation has been thought as one of most promising membrane process technology.Firstly, different concentrations of hydrofluoric acid as a surface treatment agent or PDMS membrane surface modification, increase the membrane surface roughness and chemical change, characterization of surface modification effect of hydroxyl number and through infrared spectroscopy and transmission modifying its electron icroscopy evaluation of the effect of the modified silicone rubber composite membrane with DSC,FT-IR, SEM and surface morphology of the thermal stability and hydrophdic property of the modified membrane for analysis and characterization, and ethanol/water system for the study, the study focused on the feed concentration, feed temperature, osmotic pressure,silicone rubber composite membrane separation performance impact, and by measuring the contact angle analysis of membrane and membrane flux performance of the membrane.Then PDMS silicone rubber filled with nano PTFE teflon, elution was prepared via the surface of PTFE asymmetric n-PDMS composite membrane. Using DSC, FT-IR, SEM,XRD on membrane modified thermal stability, surface morphology and structure were analyzed and characterized. When the weight ratio of n-PTFE and PDMS is 1:10, the comprehensive separation performance is the best. With the feed concentration increasing,the flux increases and the separation factor decreases; as the temperature increases, the flux increases and the separation factor first decreased and then increased.Thirdly, we used hydroxyl silicone-modified hydrophobic nano-silica to prepare a silicone rubber composite membrane. Hydroxy silicone crosslinked with the surface of hydroxyl SiO₂ to get the modified hydrophobic nano-silica in an organic solvent, n-heptane,which was heated in an oil bath to control the temperature at 98 ℃, by reacting for 50 min,the silica can get a better effect. Subsequently, the modified hydrophobic nano-silica filled silicone rubber film composite membrane was prepared. The experiment focused on exploring the preparation of hydrophobic pervaporation nano-silica silicone rubber composite membrane by changing membrane content of silica, feeding temperature,ethanol concentration, solid-liquid flow rate of the Institute of the preparation of composite membrane performance.