Study On High Frequency Vibration Membrane Reusing Coastal Oil Depot Wastewater

This paper mainly studied a high frequency vibrating membrane separation device. With the key technologies of the high strength membrane material preparation and vibration generator coupled mode breakthrough, the membrane fouling in process of oily sewage was solved, and achieved cleaner and more efficient to reuse the coastal oil depot wastewater.The main research contents include: ①Carbon nanotube enhanced membrane material was prepared, and carbon nanotubes additive concentration, casting solution temperature in the membrane formation process, optimization of casting solution composition and preparing condition; ②Influence of coupling mode, component generator and membrane vibration were researched, the effects of high frequency vibration frequency, amplitude,direction, power on the membrane filtration performance of oil depot sewage,optimization design of high frequency vibration membrane device; ③The basic characteristics of coastal oil wastewater from the comparative study of dynamic membrane and static membrane, to explore the influence of vibration on the concentration polarization lighten membrane fouling and, revealing the action mechanism of vibratory shear enhanced membrane filtration. Through the above study, the following conclusions are obtained.(1) Carbon nanotube modified PVDF ultrafiltration membrane, to obtain surface uniform membrane, the hydrophilicity of membrane surface increased significantly. With the increase of the amount of carbon nanotubes, ultrafiltration membranestrength was first decreased and then increased and then decreased, when the concentration of CNTs is 0.3%, the maximum intensity of ultrafiltration membrane.(2) 0.3% the content of carbon nanotubes PVDF ultrafiltration membrane made of hollow fiber membrane modules, based on the dynamic shear enhanced membrane filtration principle, the electromagnetic suction type vibration and internal pressure type hollow fiber column membrane are coupled, high frequency vibration shear design and manufacture of enhanced membrane filtration system has better performance.(3) Vibration shear is feasible in reasonable operating conditions, horizontal vibration than the vertical vibration of membrane flux can get bigger, can generally be 3.5%~10.5% more than the vertical vibration,. Vibration shear filtering than static cross flow filtration membrane permeation flux is higher than 45%~75%.(4) Vibration frequency of size effect on the membrane permeation flux is nonlinear, can obtain the maximum permeate flux in the frequency range of suitable, this study found that the vibration frequency is 80~110Hz, the membrane system to obtain the best filtering ability, and in the 60-70 Hz range will cause equipment resonance phenomenon, is not conducive to themembrane normal operation(5) The permeate flux increased gradually as the transmembrane pressureincreases, pressure difference effect size liquid flux across the membrane, the permeate flux of membrane system increases with the increase of liquid flow. Liquid concentration on membrane flux, concentration of feed solution morewill make the permeate flux decline more.(6)Compared with conventional crossflow filtration system, the high frequency vibration shear ultrafiltration membrane system can reduce more effective concentration polarization and membrane fouling, Vibration membrane for oil retention rate of 99.49%. The oil content of oily wastewater treatment leachate obtained for 0.436mg/L, to achieve wastewater reuse industrial(less than 1mg/L) requirements.