A Study On The Filtration Properties Of Fiber Inorganic Ceramic Nanofiltration Membrane

The characteristics and filtration mechanism of fiber inorganic ceramic nanofiltration membrane (ICNM) were studied in this pager. The applying feasibility of nanofiltration technology in water treatment and refining extract of Chinese Traditional Medicine were also investigated. Thus they can provide some valuable experimental data for the industrial application.Pure water flux measurements showed that the permeability of membrane was 55.07L/m2·h·MPa and the membrane resistance was 6.505×1013m-1. For a certain 0.002mol/L MgCl2 solution the isoelectric point of membrane was 3.4, and the membrane charge was negative and positive with the solution pH>3.4 and pH<3.4 respectively.The retention effects of fiber ceramic membrane on the MgCl2 solution were studied to test its applying feasibility in water treatment. The separation performances were investigated with the working pressure, pH and concentration changed. The retention rate of the fiber ceramic membrane and the organic DK membrane (MWCO was 250) was 63% and 41% respectively, based on 0.7MPa of pressure, 0.002mol/L of concentration, 25℃of temperature and 6.8 of pH. The experiment results showed that the higher steady-state permeating flux and retention can be obtained at higher working pressure and lower concentration. The influence of pH on the separation performance mainly depends on its effect on the charge property of the ceramic membrane.Purification experiments of Flos Lonicera extract were carried out using fiber ICNM. The experiments results showed that the removal of protein & amylase by ICNM was superior to those removed by ethanol precipitation, and use much less processing time and organic solvent. So it can be used in the refining process of Flos Lonicera extract. The Higher steady-state permeate flux was obtained at higher temperature, higher feed flow rate and lower concentration. The steady-state permeate flux did not increase proportionally with the applied working pressure.The Flos Lonicera extract was selected as experiment material to investigate the mechanism of membrane fouling and cleaning method. The fouling grain ceramic membrane was cleaned with de-ionized water, 0.2%NaOH solution and 1%NaClO solution in turn. After that the pure water flux recovery of the membrane was 71%. The fouling fiber ceramic membrane was cleaned with de-ionized water and 0.2%NaOH solution ordinally, and the pure water flux recovery could attain 86%. The regenerating ability of fiber ceramic membrane is better than grain ceramic membrane.