gases like CO , N , Cl , O and He, alumina and silica are employed. In the blast furnace silica gel is also used for drying air. . One of the highly important use of adsorption is the softening of hardwater.
Permutit is employed for this process which adsorbs Ca + and Mg + ions in its surface, there is an ion exchange as shown below it occurs on the surface. Na Al Si O +CaCl CaAl Si O 2NaCl Exhausted permutit is regenerated by adding a solution of common salt. CaAl Si O +2NaCl Na Al Si O +CaCl . Ion exchange resins Ion exchange resins are working only based on the process of adsorption.
Ion exchange resins are used to demineralise water. This process is carried out by passing water through two columns of cation and anion exchange resins. RSO H+Ca (Mg RSO ) Ca(Mg)+2H + + → ( resin minerals in water resin with mineral N + OH - +Cl - (SO - ) (SO - ) R R R R N + Cl - + OH - R R R R resin minerals in water resin with mineral . Petroleum refining and refining of vegetable oil Fuller’s earth and silica gel are used for refining process.
. Decolourisation of Sugar: Sugar prepared from molasses is decolourised to remove coloured impurities by adding animal charcoal which acts as decolourising material. . Chromatography The chromatographic technique is applied for separation of components in a mixture.
It is mainly based on adsorption of components on the surface of adsorbents. This method is very effective and used for identification, detection and estimation of many substances even if they are contained in micro quantities. XII U10-Surface XII U10-Surface - - - - . Catalysed reaction Catalysis is an important branch of surface chemistry which is based on the phenomenon of adsorption of materials on the catalyst surface.
Examples: In the Haber’s process, ammonia is manufactured