Preparation of nano particles

PREPARATION OF NANO PARTICLES

1. DEPARTMENT OF CHEMISTRY TKMM COLLEGE NANGIARKULANGARA

2. PREPARATION OF NANOPARTICLES SOL-GEL SYNTHESIS COLLOIDAL PRECIPITATION CO-PRECIPITATION COMBUSTION TECHNIQUE HYDROTHERMAL TECHNIQUE HIGH ENERGY BALL MILLING SONOCHEMISTRY

3. SOL - GEL SYNTHESIS Wet chemical technique Chemical solution deposition For gel like properties particle density shoud be increased by removing significant amount of solvent SOL GEL

4. Increase in particle density/decrease in solvent can be done by Sedimentation Centrifugation Drying process ( shrinkage and densification) Thermal treatment/firing process ( favour polycondensation , enhance mechanical properties and structural stability via final sintering,densification and grain growth )

5. Densification can be achieved at a much lower temperature Sol-gel approach is a cheap and low temperature technique that allows for the fine control of products’ chemical composition

6. SOL - GEL SYNTHESIS

7. COLLOIDAL PRECIPITATION Synthesis of nano particles of gold,silver Tetrachloroauric acid trisodium citrate( reductant ) Gold particles (purple colour ) H Au +3 Cl 4 Au Frens-Turkevich method

8. COLLOIDAL PRECIPITATION

9. CO-PRECIPITATION Simple and low cost process Applicable to preparation of magnetic nano particles Iron oxide nano particles are synthesised by co-precipitation reaction of FeCl 3 and 1,2,4,5-benzene tetracarboxylic acid

10. Experimental procedure FeCl 3 , NaOH and 1,2,4,5-benzene tetracarboxylic acid are dissolved in water and shaked for 10 minutes Filtered and dried in air Obtained powder is calcined at 450 C for 2 hours Iron oxide nanoparticles are obtained

11. Morphology of Fe 3 O 4 powder consists of cubic phase with size of 24 nm FT-IR , XRD and SEM are used to characterise the product

12. COMBUSTION TECHNIQUE Used for the preparation of nano particle sized LiBiO 2 Requirements Lithium Nitrate bismuth Nitrate Urea (igniter-fuel ) Glycerol (binding material)

13. Experimental procedure Lithium Nitrate and Bismuth Nitrate are mixed together to form a uniform mixture Required quantities of urea and glycero l are added to form a homogeneous paste Pre-heated at 150-200 c to form a dried mass Calcined at 460 c for 5 hours Nanoparticles of LiBiO 2 are obtained

14. HYDROTHERMAL TECHNIQUE Conducted in steel pressure vessels called autoclaves with or without teflon liners Under controlled temperature and/or pressure with the reaction in aqueous solution Widely used for the production of small particles in ceramics industry Used to prepare nanoparticles of TiO 2

15. HYDROTHERMAL TECHNIQUE AUTOCLAVE

16. Synthesis of nanoparticles of TiO 2 Hydrothermal treatment of peptized precipitate of a titanium precursor with water Precipitates are prepared by adding 0.5M isopropanol solution of titanium butoxide into deionisde water They are peptized at 70 C for 1 hour in the presence of tetra alkyl ammonium hydroxide ( peptizer ) Filtration and treatment at 240 C for 2 hours Obtained powder are washed with deionised water and absolute alcohol Dried at 60 C

17. Under the same concentrations of the peptizer ,the particle size decreased with increasing alkyl chain length The peptizers and their concentrations influenced the morphology of the particle

18. HIGH ENERGY BALL MILLING

19. HIGH ENERGY BALL MILLING Utilized in industries to perform size reduction Induce structural changes and chemical reactions by mechanical energy rather than thermal energy ,reaction are possible at room temperature and so non-equilibrium in nature The milling process embraces a complex mixture of fracturing, grinding , high speed plastic deformation , cold welding , thermalshock , intimate mixing etc . Produced a large range of nanoscaled materials – nanocrystalline materials , nanoparticles , nanocomposites , nanotubes , nanowire s and nanorods

20. Terms used to distinguish powder particle behaviour in milling Mechanical Alloying (MA) Mechanical Milling (MM) Mechanochemical Synthesis (MS)

21. Mechanical Alloying (MA) Mixtures of powders are milled together Material transfer is involved A homogeneous alloy is obtained

22. Mechanical Milling (MM) Only powder with uniform composition is milled No material transfer is involved

23. Mechanochemical Synthesis (MS) A special MA process Chemical reaction between the powders take place during milling Grain refinement and chemical reactions take place at low temperature under far from equilibrium conditions Cold welding and Agglomeration during milling opposes MA and MM

24. Nanocomposite mixtures formed during mechanochemical reaction can be further processed into nanoscale particles Nano composite of Fe and NaCl was obtained by milling FeCl 3 and sodium metal FeCl 3 + 3 Na → Fe + 3 NaCl Simple washing after milling dissolves NaCl and nanoparticles of Fe can be obtained

25. Inherent advantages in processing nanomaterials via high energy ball milling technique Excellent versatility Scalability Cost effectiveness

26. DEPARTMENT OF CHEMISTRY TKMM COLLEGE NANGIARKULANGARA