Study And Application Of Electrochemical Modified PVDF Ultrafiltration Membrane

Membrane separation technology is widely used in water pollutant treatment techniques due to its low energy consumption,easy replacement of equipment,convenient operation and low secondary pollution.However,owing to unique hydrophobicity of most organic molecule and the characteristics of low surface energy,Improving the Hydrophilicity and high throughput of organic polymer membrane is an urgent need to resolve,and also a barrier to be broken in the long-term development of future membrane technology applications.This paper takes hydrophilic modification of Polyvinylidene fluoride(PVDF)ultrafiltration membranes as the research content,By Alkali before acid,pretreats with lye,and modifies by electrochemistry,the C-F groups on the surface of PVDF hollow fiber membrane is eliminated to form a carbon-carbon double bond,and improves the hydrophilicity of the membrane surface and increases the membrane flux through acid oxidation formed by electrochemical effect.In study,the performance changes of membrane filaments prior and post to modification were compared by characterization of membrane filaments such as scanning electron microscope,infrared spectrum and other performance parameters,membrane flux,molecular weight cutting and application of grease wastewater.we investigate the effects of technological parameters such as lye concentration,alkali leaching time,reaction voltage,electrode flow rate ratio,modification time on the performance changes of membrane filaments.The results show that: Soak PVDF material in 0.5% Na OH alkali solution for5 min,Under the condition of 10 V voltage and 1:1 effluent ratio of anode and cathode,The pure water flux increased from 550L/(m2×H)to 825L/(m2×H)of untreated membrane wire at 2 hour after electrochemical modification.and the increase ratio was 50%.Through the retention test of bovine serum protein with molecular weight of 67 KDa,110KDa and 200 KDa dextran,it was found that while the oxidation time increases,the retention efficiency is gradually decreasing,Combining the relationship between oxidation time and flux,the most suitable experimental group for the retention efficiency and flux growth is the oxidation time of 1 hour.It can be found that the peak value of-OH has a significant increase at 3400～3200 cm-1 by FTIR characterization of the membrane filament,and the peak value of the modified membrane filament at 1540～1850 cm-1 for C=O and C=C is significantly higher than that before modification.