Settling down of heavier insoluble particles/ solids from a mixture is called sedimentation. Like mud settles from muddy water.
Decantation is pouring out of upper clear layer of liquid into another container to separate two immiscible liquids. Like draining oil from a mixture of oil and water after allowing the two to separate and form distinct layers
Filtration is the process of separating insoluble impurities from a solution. When a solution is passed through a filter, particles with pore size bigger than that of the filter are retained while others pass through. Like filtering mud from muddy water
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