The Main Function, Classifications, and Properties of Filter Paper

The main component of filter paper is cotton fiber. There are many small holes on the surface of the filter paper that allow liquid particles to pass freely, while those larger solid particles, will be blocked outside and cannot pass through the filter paper. It is precise because of this property of filter paper that it can separate liquid and solid substances very well. In addition to the experimental analysis, filter paper is also widely used in our daily life. Today, HAWACH will discuss the function of filter paper, classifications, and some basic properties.

Filter paper function

The main function of the filter paper – chromatography: because the cotton fibers in the filter paper have a good affinity with water, it can absorb about 22% of the water, of which the water combined with cellulose in the form of hydrogen bonds has 6% to 7%.


Compared with the affinity with water, the affinity of cotton fibers in filter paper with organic solvents is weaker, so in most cases, paper chromatography is to remove the filter paper fibers. The combined water is used as the stationary phase, and the mobile phase is mainly the organic solvent. When the mobile phase of the organic solvent passes through the sample, the water, and the organic phase are continuously distributed, and then with the continuous movement of the mobile phase, the substances of various components are continuously redistributed, which further enables the substances to be separated. and purification. Filter paper is frequently used in chemical laboratories.

Filter paper classification

The main classification of filter paper: In general, filter paper can be divided into two types, one is qualitative filter paper and the other is quantitative filter paper. Qualitative filter paper generally refers to the formation of cotton fibers on its surface after filtration, which is generally only suitable for qualitative analysis. Quantitative filter paper is generally aimed at ashless filter paper. It must undergo special treatment procedures during use. To a certain extent, it can effectively resist certain chemical reactions, so impurities generated on its surface are generated. will be much less, usually, it is generally used in quantitative analysis. In addition to the application of filter paper in chemical experiments, we also have the application of filter paper in our lives. For example, coffee filter paper is one of the widely used ones. Generally, this filter paper has a high degree of softness, while in industry filter paper It is generally used to adsorb suspended particles in the air.

Filter paper properties

The basic properties of the filter paper: the selection of the appropriate filter paper must be determined by the following four factors. The first is hardness. The filter paper will be wet during filtration, so in the long-term filtration process, you should Choose a tougher filter paper. The second is its filtration efficiency. The filtration efficiency is mainly determined by the tightness of the water seepage pores on the filter paper and the size of the pores. Then there is the capacity. The capacity is mainly determined by the density of the water seepage pores. The denser the pores, the higher the capacity. The last is applicability. The production steps of some filter papers are very special, so we must pay attention to them when applying them. It should be noted that the filter paper cannot filter zinc chloride, because it will corrode and damage the filter paper.

The above is a brief introduction to the function of filter paper, classifications, and some basic properties. If you would like to learn more about the filter paper, contact HAWACH directly.