Techno Economic Self Optimisation of Cards
Depositing polyvinyl alcohol nanofibers on the surface of the non woven aerosol filter media using needleless electrospinning technique. The diameter of the nanofibers were between 48 to 57 nm. The filtration efficiency was evaluated by measuring the filtration of sodium chloride nanoparticles (75+ 20 nm) through the filters. The filtration efficiency of the modified filter media for nanoparticles was increased along with the thickness of nanofibers mats which was controlled by the collection time during the electrospinning. The high filtration efficiency was achieved through the multi layer arrangement. This modified filter has higher quality factor and less mass in comparison to particulate air (HEPA) filters which has the same filtration efficiency. Introduction For the past decades, pollution has increased greatly all over the world [1] Air pollution occurs when harmful substances including particulates an biological molecules are introduced into Earth's atmosphere [2] It may cause diseases, allergies or death of humans. PM stands for particulate matter (also called particle pollution) the term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope. PM2.5 fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller [3] Filtration by fibrous filters is one of the most widely used techniques to capture fine particles rom a gas stream. The process takes place by passing the aerosol Through PM stands for particulate matter (also called particle pollution) the term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope. Particle pollution includes: the filter media, so that the particles will be deposited on the filter surface [4] Needle electrospinning has Low flow rate which has restricted the application of on an industrial scale. Multiple needles was proposed to solve this problem but there was a problem that the electric field distribution much more complex. Needless electrospinning was invented to overcome the low flow rate problem as It has higher fiber throughput also it has many two important advantages simpler structure, and more uniform electric field. PVA is an atactic material that exhibits crystallinity [5] Polyvinyl alcohol has excellent film forming, emulsifying and adhesive properties. It is also resistant to oil, grease and solvents [5] It has high tensile strength and flexibility, as well as high oxygen and aroma barrier properties. However these properties are dependent on humidity, in other words, with higher humidity more water is absorbed[5] In this study, PVA nanofibers was produced with diameters 48 to 57 nm on the surface of the non woven aerosol filter media by needleless electrospinning. The high filtration efficiency was achieved through the multi layer arrangement was up to (99.95% This modified filter has higher quality factor and less mass in comparison to particulate air (HEPA) filters which has the same filtration efficiency. Methods Materials Materials PVA, (Mw 85,000 124,000, 99+ hydrolyzed was bought from Sigma Aldrich Chemie Gmb. Taufkirchen, Germany. Needleless electrospinning began to attract attentions since Chaloupek etal.'s invention [9] on using a metal roller as spinneret. The setup in our laboratory is shown in Figure 2. A stainless steel roller was used as the generator of jets. The polymer solution was transferred into the upper surface when the rotated roller was partially touched the polymer solution. A large number of jets can be obtained from the roller surface after applying a high voltage. The produced nanofibers was collected on Another grounded roller. Figure 2 Lab Needless Electrospinning Deionized water is water that does not contain any impurity ions. In fact it is perfectly cleaned water. Deionized water is produced by the chemical purification of the artesian water from salts, metals, trace elements and micro particles using special ion exchange equipment[6].It was produced using Direct Q(r) systems from HACH co,USA. PVA solution was prepared by dissolving the PVA polymer in deionized water at 80degC and 1500 rpm, and completely dissolved by stirring. 50 KV (HPS 350W, iseg Spezialelektronik GmbH) was applied on the positive roller for electrospinning which was rotated by separated motor. The distance between the 2 collector was designed to be constant at 10 cm. The non woven filter was fixed on the collector and after switching on the High voltage the nanofibers were transferred into the surface of the filter to form a composite filter. It was dried under vacuum condition to remove the remaining solvent for the filtration test. PVA solutions can form physical gels [10] which have fine adhesive properties. There is any possibility for the slippage of PVA nanofibers after the solvent was evaporated. Characterization The penetration efficiencies of the filter was measured by using Automated Filter Tester Model 3140 The weight of the filter was measured before and after adding the nanofibers to determine the weight of the nanofibers using Sartorius precision balance from Mesdan SPA,Itly. The thickness of the Filter was measured before and after adding the nanofibers to determine the thickness of the by the thickness gauge Measuring depth 30 mm and accuracy 0,001 mm from Mesdan SPA,Itly. The viscosity of PVA solutions was tested by using Rotational viscometer Model 3220A, from Mesdan SPA. The structures and diameter distribution of the composite filter were examined SEN model Q250 from FEI USA. Results and discussion PVA nanofibers Different concentrations (from 3% to 12 were used inside the tank solution under the cylinder. Figure 3 shows that the lower solution concentration (3% as compared to 12 PVA) in this study yields smaller average fiber diameter as compared to higher concentration. Figure 3. Effect of Solution Concentration on Fiber Diameters. As it can be seen from the figure 4 that the concentration below the 6 caused beads. The uniform formation of PVA nanofibers was achieved with increasing the concentration to 6% ,9 and 12 .Also the diameter was increased with the concentration. Figure 4 The SEM images of PVA nanofibers which was produced using different concentrations on PP substrate: (a) 3 wt. (b) 6 wt. (c) 9 wt. (d) 12 wt. The nanofibers mat over the pp. filter had many thinness depending on the controlled working time and the relation between the thickness The penetration efficiencies was studied and can be seen in figure 4. Figure 4. The filtration efficiency and the thickness of nanofibers. Contact Information Mohamed Abd Elzaher Mohamed Elsharkawy Research Assistant. Textile Research Division. National Research Centre. P.O. Box 12622, Dokki, Giza, Egypt. Mob +2 01090669643 E Mail: M.Elsharkawy.tex@gmail.com Enhancing air filtration efficiency using needleless electro spun nanofibers Mohamed Abd Elzaher Mohamed Elsharkawy Textile Division, National Research Centre 10 20 30 40 50 60 70 80 90 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 D ia m e te r n m Concentration Diameters nm