Filter paper can be divided into qualitative and quantitative. In the application of analytical chemistry, when the inorganic compounds are filtered to separate the precipitates, the residue collected on the filter paper can be used to calculate the loss rate in the experiment process. Qualitative filter paper can only be used for qualitative analysis because there are more cotton fibers generated after filtration; quantitative filter paper, especially ash free filter paper, can resist chemical reaction effectively after special treatment procedure, so the impurities generated are less, which can be used for quantitative analysis. In addition to the general laboratory application of filter paper, there are many applications of filter paper in life and engineering. Coffee filter paper is one of the widely used filter paper. The filter paper on the outer layer of tea bag provides high softness and wet strength. Other air filter paper used to test suspended particles in the air, and fiber filter paper used in different industrial applications, etc.
