Inhibition of membrane fouling by frequency agility electric field in desalination

Abstract

In order to address the issue of RO membrane fouling in desalination, this research provides a technique for reducing RO membrane fouling by employing a frequency agility electric field. In this paper, a frequency agility electric field device is applied. The delta type underdamped damping oscillating signal with high speed random variation in frequency range of 80–300 kHz is developed. The signals were applied to a circulation experimental system which simulated seawater solution as working medium. The quality parameters and separation properties of RO membrane permeant and the morphology of scale on the membrane surface were analyzed experimentally. In this process, the energy consumption of the device is 3 W, and no wear will be caused to the permeable membrane during this process. The results show that under the condition of using electric field device, the salt rejection and flux of the membrane are increased by 15% and 35% respectively, the conductivity values and total dissolved solids(TDS) values of the permeate are decreased by 25% and 20% respectively, and the membrane pressure is reduced by 25%. In addition, the thickness of the crystals attached to the surface of the membrane is reduced, and the crystal clusters become smaller and sparser. The frequency agility electric field can effectively inhibit membrane fouling in desalination.