dispersion method (simple dissolving): In these methods, larger particles of a substance are broken into smaller particles which then mixed with the dispersion medium to get a suspension. The suspension is then grinded in colloidal mill. Hydrophilic colloids are mostly prepared by this method Colloidal solutions of black ink, paints, varnishes, dyes etc. are obtained by this method. B.Condensation method : In this method smaller particles are condensed in into colloids particles .Hydrophobic colloids are mostly prepared by condensation method.
The different components of the ink mixtures travel accordingly to different rates. The mixtures are then separated into different coloured spots depending on the compound's preference. The mobile phase is solvent in thin and paper chromatography.. Acetone is generally used as dipping reagent in chromatographic process because it shows the characteristics of a good solvent since it is important to choose a solvent for the color reagent in which the substances to be detected are insoluble (Joseph Sherma, 2013). Capillary action causes the solvent to flow up the paper at a uniform rate. A line called as solvent front is created across the paper .As the solvent level increased; the solvent dissolved the ink into its components.
It is also used as a plasticizer and in film coatings Glycerin is used as a plasticizer of gelatin in the production of soft-gelatin capsules. Stability and Storage Conditions Glycerin is hygroscopic. Pure glycerin is not prone to oxidation by the atmosphere under ordinary storage conditions but it decomposes on heating with the evolution of toxic acrolein. Mixtures of glycerin with water, ethanol (95%), and propylene glycol are chemically
Irradiation of a liquid by ultrasound causes cavitation threshold when the pressure amplitude of the applied sound source reaches a certain minimum. In an oil and water system, the process of emulsification occurs when the cavitation threshold is attained. Ultrasound provides an excess energy for new interface formation; hence it is possible to produce emulsions even in the absence of surfactants (emulsifiers) (Ref- M2, N4,) Ultrasonication has been used extensively for producing nanoemulsions of drugs and food ingredients. (Ref- 33, U1, U2) QSONICA-Q125 Sonicator (Ref- 6) Low energy methods:- As the name suggests, low-energy emulsification methods require low energy for
1.4 Breath figure method Breath figure method consists of the following steps: a) A polymer solution is made using a volatile solvent in which the polymer easily dissolves. b) This is immediately cast onto a casting surface in a sufficiently humid environment. The technique used is the drop-casting method6. c) The solvent is allowed to evaporate till the polymer is left behind as a solid film. d) The film is then characterized to note the kind of pores formed.
2AuCl3 + 3SnCl2 → 3SnCl4 + 2Au c) Hydrolysis: It is the break down of water. Sols of ferric hydroxide and aluminium hydroxide can be prepared by boiling the aqueous solution of the corresponding chlorides. for example. FeCl3 + 3H2S → Fe(OH)3 + 3HCl In milk, the colloidal suspension of the fats prevents the milk from being thick, and allows for easy absorption of the nutrients. Sewage water contains particles of dirt, mud etc.
Typical precursors are metal alkoxides and metal chlorides, which undergo hydrolysis and polycondensation reactions to form a colloid. The sol then evolves towards the formation of an inorganic network containing a liquid phase called gel. In this method, the substrate is dipped into the solution, taken out and dried by allowing the solvent to evaporate, leaving behind a solid film on the
HPLC is an improved form of column chromatography. It uses high pressures to force the solvent through the column instead of just using gravity. By using much higher pressure than normal, the process becomes much faster and it allows the use of smaller particle size for the column packing material. Having smaller particles gives a larger surface area for interactions between the stationary phase and the molecules flowing through it which means better separation. Absorbance There are two main ways HPLC are used, normal phase and reverse phase.
Freeze crystallization can be applied in separation processes to either purify or concentrate a material, depending on the desired end product. As the solvent crystallizes, the solute is concentrated in the remaining liquid solvent. The purified crystals are removed from the impurity laden liquid (for example by gravity, filtration or centrifuging) and may be used in the solid phase or melted for use as a refined liquid. In some applications, the concentrated liquid may be the desired end product like Phenol and Acrylic
Alkaline oxygen delignification (O) is ideal for kraft operation as it takes oxidized white liquor as an alkali source and it spent liquor is reused in the kraft digester counter wash. Oxygen is poorly soluble in alkali so needs a stable gas/liquid/solid dispersion, all reactions occur at the solid-liquid interface preferably in a high consistency pulp. Oxygen delignification is complex and involves free radical mechanisms. The treatment will remove half the residual lignin without serious cellulose