What are colloids?

Colloids are mixtures in which very small solid particles remain dispersed throughout a liquid without settling out. These particles are typically too small to be seen individually, yet they are large enough to affect the properties of the liquid, such as its viscosity or its ability to scatter light (this is known as the Tyndall effect). Because of their fine size, colloids do not settle out under the influence of gravity, which distinguishes them from larger solid particles that may dissolve or precipitate out of a solution.

Understanding colloids is important in water treatment processes, as they can significantly influence the effectiveness of various treatment techniques. For instance, certain filtration methods may not effectively remove colloidal matter, which can carry contaminants and other impurities in the water system. This makes it necessary to employ additional processes, such as coagulation or sedimentation, to handle colloids appropriately.