Eco friendly in textile processing


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Eco friendly in textile processing

  1. 1. Eco Friendly In Textile Wet Processing By Aravin Prince Periyasamy 1
  2. 2. SupercriticalCarbon Dioxide 2
  3. 3. What is supercritical carbon dioxide? A supercritical fluid is a substance above its critical temperature and critical pressure. Under these conditions the distinction between gases and liquids does not apply and the substance can only be described as a fluid. 3
  4. 4. Supercritical Fluid of CO2 4
  5. 5. Above 31.10C and 73 atm carbondioxide behaves as a supercritical fluidand shows properties of both a liquidand a gasIt fills the container, like a gas, anddissolves substances like a liquid. 5
  6. 6. Supercritical fluid of CO2  With an increase in temperature the meniscus begins to diminish.  The liquid density falls due to expansion and the gas density rises as more of the substance evaporates. 6
  7. 7. Supercritical fluid of CO2  Once the critical temperature and pressure have been reached the two distinct phases of liquid and gas are no longer visible. The meniscus can no longer be seen. One homogenous phase called the "supercritical fluid" phase occurs. 7
  8. 8. Industrial extraction with supercritical CO2 Decaffeinating coffee and tea Extracting bitterness to make beer Defatting cocoa powder Extracting spices and aromatic plants 8
  9. 9. Significant properties of supercritical fluidsDiffusivity gas > supercritical fluid > liquidViscosity gas < supercritical fluid < liquidSurface tension gas = supercritical fluid < liquidDensity gas < supercritical fluid < or = liquid 9
  10. 10. Benefits of using supercritical CO2 for extraction It is having the penetration power of a gas and the extraction power of a liquid. It acts as a solvent to extract organic compounds with a low molecular weight. It leaves no residual trace on treated material It respects the environment. 10
  11. 11. Supercritical CO2 as solvent Purification of specialty chemicals and useful natural products An alternative solvent in coatings industry (replacing 40 - 90% of volatile solvents) Degreasing and dry cleaning applications Increasingly applied as a solvents in synthetic industrial processes 11
  12. 12. Use of supercritical CO2 in dyeing processes 12
  13. 13. Use of supercritical CO2 in dyeing processes 13
  14. 14. Enzymes 14
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  16. 16. Electron-ray treatment 16
  17. 17. MicrowavesMicrowaves are electromagnetic waves whosefrequency ranges from 1000MHz to10,00,000MHz.Microwave dyeing takes into account only thedielectric and the thermal properties.The dielectric property refers to the intrinsicelectrical properties that affect the dyeing bydipolar rotation of the dye and influences themicrowave field upon the dipoles. 17
  18. 18.  The aqueous solution of dye has two components which are polar, in the high frequency microwave field oscillating at 2450MHz. It influences the vibrational energy in the water molecules and the dye molecules. The heating mechanism is through ionic conduction, which is a type of resistance heating. Depending on the acceleration of the ions through the dye solution, it results in collision of dye molecules with the molecules of the fiber. This helps and affects the penetration of the dye and also the depth to which the penetration takes place in the fabric. This makes microwave superior to conventional dyeing techniques 18
  19. 19. Ultrasonic Treatments 19
  20. 20. Electrochemical dyeing Vat and sulphur dyeing involves both a reducing and an oxidising step, which are carried out with chemical oxidants and reducing agents. The environmental concerns associated with the use of these chemicals are many. An attractive alternative technique is to reduce and oxidise the dye by means of electrochemical methods.With direct electrolysis the dye itself is reduced at the surfaceof the cathode. In indirect electrolysis the reducing power ofthe cathode is transferred to the solution by a solublereversible redox system (e.g. based on antraquinone chemistryor iron complexes). With this reversible redox system thereducing agent is continuously regenerated at the cathode,which thus allows full recycling of the dye bath and thereducing agent. Direct cathodic reduction in an electrochemical cell is applicable to sulphur dyes. Vat dyes are reduced by indirect 20 electrolysis.
  21. 21. Plasma Treatment 21
  22. 22. 4th State of Matter Plasma Electrically neutral +ve, -ve Charges, Radicals, Electrons, Excited molecules, atoms. Highly Reactive & Energetic 22
  23. 23. Sun Lightening boltHydrogen Bomb Fire 23
  24. 24. Thermal Plasma Cold Plasma Hybrid PlasmaRT to Over 50,000°C 24
  25. 25. Thermal Plasma Thermal Equilibrium Between Neutral Particles and the Charged Particles > 50,000°c 25
  26. 26. Principle Potential Difference > Dielectric Strength 13.56MHz RF Power 26
  27. 27. Gases UsedNon-polymerizing Gases He, Ar, Air, Oxygen, Nitrogen, And Mixture Of GasesPolymerizing Gases Cf4, C3f6 27
  28. 28. Major ApplicationsSynthetic Fibres/films Wettability Water Repellency Dyeability 28
  29. 29. …..Major Applications….Synthetic Fibres/filmsDeep Shades •Soil Release Properties •Composite Applications 29
  30. 30. …..Major Applications….Natural Fibres •Shrinkage resistance •Dyeability •Fastness properties 30
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