how can u get rid of light insoluble impurities from water?
Answers
Answer:
The solvent can be separated from insoluble impurities by using filtration. The solution thus obtained will contain solvent along with soluble impurities. This mixture can be separated by using evaporation
Process # 1. Removal of Suspended & Dissolved Impurities:
Removal of coarse, dispersed and colloidal impurities from water is known as clarification. These impurities may be removed either by filtration or by sedimentation.
(a) Sedimentation:
The simplest way to clarify muddy water is to allow the suspended material in it to settle, the process is known as sedimentation. In filtration the water is clarified by passing it through a porous material, which retains coarse impurities on its surface and in its pores.
(b) Filtration:
The apparatus used for filtration is called filter and the porous material that fills the filter is known as filtering material or medium.
The process of sedimentation allows solid particles to settle down on the bottom of the settling tank in which water undergoing clarification is at rest or in slow horizontal or upward notion.
(c) Coagulation:
Silt particles are small enough to remain in colloidal suspension that cannot removed by sedimentation. The process of coagulation is used to remove colloidal particles from water.
The process of consolidation of colloidal particles, terminating in precipitation of the substances removed from the treated water by settling or filtration is called coagulation.
The reverse process of coagulation i.e. conversion of a solid into a colloidal state, is called peptization. Reagents that are able to provoke coagulation of natural colloids in water are coagulants. Few examples of coagulants are ferrous sulphate (FeSO
4.7H2O), aluminium sulphate [Al2(SO
4)3.18H2O] and ferric chloride (FeCl3).
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(d) Flocculation:
The process of coagulation could be improved by adding special reagents known as flocculants. Flocculants are the particles absorbed on the dispersed particles and on coagulants flakes to convert them into particles of reasonable large size and high stability. Starch, sodium polyalginate, polyacrylamine etc. are examples of flocculants.