Low-adsorbing track-etched membrane

Transcription

1 Low-adsorbing track-etched membrane Pulane Mokoena, Mantwa Lephoto and Hlamulo Makelane Supervisor: Prof. Alexander Nechaeff Flerov Laboratory, JINR, DUBNA, September 2014

2 Outline Introduction Methodology Results and Discussion Conclusion Acknowledgements 2

3 What is a track etched membrane? Introduction A membrane is a thin, porous film through which a fluid (liquid/gas) is filtered in order to carry out a separation Track-etching technology Irradiation using swift/heavy accelerated ions (Xe, Ar, Kr). During chemical etching, the damaged zone of heavy ion track is removed and transformed into a hollow-channel Figure1: Preparation of track-etched membranes It is a pore-sizedetermining and poreshape-determining stage of technology 3

4 Track-etch membrane technologies: Accelerators: Cyclotron or linear accelerator Nuclear reactor (not using nowadays for TM) Advantages no radioactive contamination of the material when the ion energy is below the Coulomb barrier identity of bombarding particles = all tracks show the same etching properties it is easier to control the impact angle and produce arrays of parallel tracks or create some particular angular distributions for getting rid of merging pores Disadvantages the stability of the particle flux from an accelerator is usually lower; a higher cost of irradiation. 4

5 Application of track-etched membranes Polishing and sterilization of filters for wide range of water treatment processes and food industry Gas separation and air filtration Medicine (artificial lungs, kidneys and plasmapheresis) Example: Figure 2: Example and explanation of water treatment track membrane 5

6 Aim of investigation To induce hydrophilicity properties on polymers, using for TM by Corona treatment for further surface modification To investigate the rate of Corona treatment i.e. percentage power used and speed of treatment To investigate the effect of contact angle on corona treated polymer surface Baseline study of the polymer material 6

7 Methodology A B C Figure 3: (A) Raw material of polymer (B) DSA 100 machine (C) Water syringe 7

8 A B C Figure 4: (A) Corona discharge machine,(b) Control panel of Corona discharge machine,(c) Group members controlling rate of Corona treatment 8

9 Corona treatment Corona treatment is a visible electrical discharge which occurs when a high voltage, frequency electrical potential is applied to a small diameter in relatively close proximity to an electrical ground. The discharge causes partially ionization of the surrounding atmosphere and used for surface modification. The higher energy discharged from this treatment attracts the molecular bonds of the polymer on the surface. The molecular bonds on the surface detach and are free to attach to the free radicals from the corona discharge environment. 9

10 Results and Discussion The kinetic relaxation of hydrophilic-hydrophobic properties of the film Figure 5a: Measurement of contact angle of polymer surface material 10

11 Conclusion The corona treatment was successful in treating the polypropylene surface of the films used for TM. P = 900W, v= 0.4cm/s Contact angle relaxation was changing exponentially, not linearly. 11

12 Future work Analogue study of polyethelene terephthalate (PET) / polyamide (PI). The study of the corona treatment of the polymer membranes. The adsorption study of dyes and proteins on polymer membrane after corona treatment. 12

13 Acknowledgements National Research Foundation South Africa Department of Science and Technology Joint Institute of Nuclear Research Professor Alexandra Nechaeff Co- supervisor: Dr Yriy Kochnev, Mr Olushola Rotimi Adeniyi and Miss Olga Artoshina Colleagues 13

14 Captured by Olu