Knowledge of Filter Papers

Filter paper has excellent filtration property and strong absorption performance on liquid. Scientific workers use filter paper as a kind of media in analytical laboratories to separate solution from solid. Currently, there are mainly three kinds of filter papers which can be purchased in domestic market: quantitative filter papers, qualitative filter papers, and chromatography qualitative filter paper.

During the manufacturing processes of quantitative filter paper, the pulp is processed by hydrochloric acid and hydrofluoric acid. After washed by distilled water, most of the impurities inside the paper fiber can be filtered so that the filter paper is fit for precise quantitative analysis.

Types of Filter Paper

Domestic produced quantitative analysis filter paper falls into three types: fast speed, medium speed, and low speed. They are marked with a blue belt (fast speed), white belt (medium speed) and red belt (low speed) respectively. Commonly, there are two shapes of filter papers you find in the market: round and square. The former one is always with the diameter of 9 cm to 18 cm, while the latter one is with the dimension of 60 cm x 60cm and 30 cm x 30 cm.

General Notes of Using Filter Paper

1. Make use of natural filtration to separate the liquid from solid.
2. Considering of low mechanical strength and tenacity of filter paper, make sure of using less suction filtration.
3. It is better not to filter hot concentrated sulfuric acid or hot concentrated nitric acid through filter paper.