In this work, water diffused through Nylon 6,6 porous membranes to dissolve solid NaBH4 tablets. The dissolved NaBH4 solution with a saturated concentration back-diffused through the porous membrane by concentration difference. In order to control the NaBH4 diffusion flux, mathematical models were built to describe the solid NaBH4 tablet controlled release systems. From the time frame view-point of NaBH4 dissolution, there are two steps: (1) NaBH4 dissolution back-diffuses through the porous membrane to the bulk solution. (2) The internal NaBH4 concentration continuously diffuses through the porous membrane until NaBH4 concentration difference between internal and external approaches zero. From sensitivity analysis, design and operating variables of NaBH4 controlled release system are: The membrane thickness, porosity, membrane area, and operating temperature and external solution volume. The simulation result shows the membrane thickness and operating temperature dominate the NaBH4 flux. Finally, the experiment was set-up. The Nylon 6,6 porous membrane with a 137m thickness and 1.8cm diameter was placed between solid NaBH4 tablets and water, the values of which were 1.66g and 30g respectively. The water penetration and solid NaBH4 dissolution times are 1 sec and 2 hrs. The external NaBH4 concentration was measured by iodine titration method once every 30 mins. The experiment result fit with the simulation result.
The 2nd International Conference on Engineering and Applied Science