Asymmetric Electrostatic Field Coupled With Pervaporation Process

Pervaporation is a new energy-saving and environmental-friendly membrane separation technology developed in recent decades.It has the characteristics of large separation factor,low energy consumption and simple operation.It has wide application prospect in the fields of organic dewatering,recovery of precious organic matter in water,separation of organic compounds and so on.In addition,its separation is not limited by the vapor-liquid equilibrium,especially for rectifying method difficult to separate near boiling and azeotrope.Pervaporation has the disadvantage of low permeation flux,so it has become an important problem in the field of pervaporation separation.In this paper,asymmetric electrostatic field coupled with pervaporation was established by the asymmetric electrostatic field formed by the use of a commercially available membrane material by placing needle and plate electrodes on the permeate side and the feed side of the membrane cell,respectively.Polar molecules due to the role of electric field,the dipole moment produced a change in order to obtain an additional electric field gradient force to accelerate the migration of the electric field toward the penetration side.The effect of electric field strength on the permeation flux was studied during the process of pervaporation separation of ethanol.The effect of single needle electrode under the same operating conditions was investigated by designing several membrane cells of different size.The effect of electric field on the structure of the membrane was investigated by SEM,AFM,XPS,ATR-FTIR and contact angle test.The membrane materials were characterized by SEM,AFM,XPS,ATR-FTIR and contact angle test.The experimental results show that,under the same experimental conditions,the existence of the asymmetric electrostatic field makes the permeation flux of the traditional pervaporation increase significantly,and the increasing rate increases linearly with the electric field intensity;single-needle electrode range is certain,beyond this range,the electric field is almost no effect;The effect of the multi-needle electrode on the permeation flux is stronger than that of the single needle electrode,but the increase rate is not proportional to the number of needle electrodes;The structure of the membrane material did not change obviously after treated by high-voltage electrostatic field.