Classification and Application of Filter Paper for Chemical Experiments

According to the different cellulose of filter paper, the filtration functions and applications are all different. We have the most commonly used standard filter paper, and also we have high-temperature GF filter paper, it depends on your own choice of application.

Hawach filter papers standard type, in general speaking, we have Qualitative filter paper and Quantitative filter paper. For qualitative filter paper, we have the standard type and wet strengthened filter paper, normally wet strengthened filter paper is widely used in the cement and mineral industry. Right now we also have some special filter papers, that are widely used in the Sugar industry, cement, mineral, electronic, oil industry, lab analysis, industry filtration, and so on.

Filter papers are often used in qualitative, quantitative, and chromatographic separation experiments. The filter paper has specifications of 70, 90, 110, 125, 150, and 180 cm and different apertures. The filter paper for general qualitative folding is generally 3.5~l0u, and the diameter of the filter paper for quantitative analysis is 1~2.5u. If you want to know more about our filter paper, please do not hesitate to contact us, we would be very glad to discuss filter paper technical details with you.

1. Qualitative filter paper

The fiber of the qualitative filter paper has a high silicon content, and the ash weight after burning is large, and it is not suitable for weight analysis, and can be used for filtration, separation of inorganic precipitates, and filtration of organic recrystallization.

2. Quantitative filter paper

The pulp of the filter paper is made by digesting it with hydrochloric acid and hydrofluoric acid. The content of iron, aluminum, and silicon in the paper is very low. The weight of ash after burning domestic filter paper is less than or equal to 0.01 grams per sheet. In quantitative analysis, this weight is negligible, so it is often called “ashless filter paper”. The filtration speed of the quantitative filter paper is divided into three types: fast, medium, and slow. The different colored paper strips are marked on the filter paper tray.

The quality inspection method for quantitative ashless filter paper is as follows:

The ash test accurately weighed 10 pieces of ashless filter paper, took two of them into pieces, and placed them in two accurately weighed platinum crucibles. In a high-temperature furnace, it began to heat with a warm fire and then added high temperature. After cooling, the crucible is weighed in a desiccator to room temperature, and the average weight of each filter paper ash can be obtained by subtraction.

The test for retaining sulphuric acid sputum heats 20 ml of sulfuric acid to boiling and drops 20 liters of a solution of cesium chloride at a concentration of 1 ml/second, and continues to heat after the dropwise addition. After 30 seconds, the mixture was filtered through a filter paper to observe whether or not the filtrate had a white precipitate, indicating whether the filter paper could retain the acid sputum.

If starch is present in the starch test filter paper, it cannot be used as an analysis of carbohydrates. The method for the presence or absence of starch in the test paper is to shred the filter paper, azeotrope with distilled water, and drip a 0.01N diluted iodine solution. If blue appears, it is confirmed that starch is present.

In the test of iron in filter paper, add a drop of paper ammonium solution to the filter paper, and add a drop of hydrochloric acid. If no iron exists, there will be no thirsty spots.

Qualitative filter paper is usually used in separating application that requires not only the high purity but the consistent performance. It can Intercept the particles to the maximum extent in the qualitative range, and irrespective of the amount present as well.

By definition, we recommend using the qualitative filter paper in analytical methods. The most efficient qualitative filter paper is suitable for chemical analysis, clarification of suspended material and soil-cement analysis.

Providing the correct combination of particle retention, right filtering speed and good loading capacity, we offer the whole range of low ash qualitative filter papers for the scientists in the lab. For the consistent performance and high purity, all of our filter paper is made under tightly controlled manufacturing conditions. And all the filter paper is produced with pure cotton linters, and the ash content is less than 0.006 %.

Upon your application and different filtration speed, you can find two kinds of qualitative filter papers: standard qualitative filter papers and wet-strengthened qualitative filter papers.