The Specification of Filter Paper

Currently, there are three kinds of quantitative filter papers in the domestic market. They are fast speed, intermediate speed, and low speed, with category labels of white belt, blue belt, and red belt respectively on the filter paper boxes.

The shapes of quantitative analysis filter paper are round and square. The round filter paper specifications are classified by diameter with 9cm, 11cm, 12.5cm, 15cm, and 18cm. As for the specification of square papers, there are 60cm x 60cm and 30cm x 30cm.

hawach-filter-papers-bio-41 quantitative-filter-papers-bio-41 lab grade filter paper

Filter paper is a porous material used for various filtration applications in laboratories and industrial processes. It comes in different grades and specifications to suit different types of filtration needs. Here are some common specifications and properties of filter paper:

  1. Grade and Pore Size:
    • Filter paper is categorized into different grades based on pore size and particle retention. Common grades include qualitative (for general-purpose filtration) and quantitative (for precise particle retention).
  2. Pore Size Range:
    • Filter papers can have a wide range of pore sizes, from coarse filters for large particles to fine filters for small particles. The pore size is often specified in micrometers (µm) or millimeters (mm).
  3. Basis Weight:
    • This is the weight of the filter paper per unit area (usually expressed in grams per square meter, g/m²). Higher basis weights generally indicate denser and more robust filter paper.
  4. Filtration Speed (Flow Rate):
    • Filtration speed indicates how quickly liquid passes through the paper. Types: Fast (coarse particles), Medium, Slow (fine particles, analytical work). Choosing the right speed helps balance efficiency vs. accuracy.
  5. Size and Format: Filter paper is available in different formats:
    • Circular sheets (most common), Folded filters, Sheets and rolls
    • Selection depends on: Funnel size, Filtration setup
  6. Thickness:
    • Filter paper thickness can vary based on the intended application. Thicker filter paper provides higher loading capacity but may reduce filtration speed.
  7. Flow Rate:
    • This refers to the speed at which liquid passes through the filter paper. It is influenced by factors like pore size, thickness, and surface treatment.
  8. Particle Retention:
    • Filter paper is characterized by its ability to retain particles of a specific size. This property is important for ensuring that only particles smaller than the specified size pass through.
  9. Compatibility with Chemicals:
    • Filter paper should be chosen based on its compatibility with the chemicals and solvents being filtered. Some filter papers are chemically treated or coated for enhanced performance with specific substances.
  10. Wettability:
    • This indicates how readily the filter paper absorbs liquid. Some applications require filter paper with high wettability, while others may require low wettability.
  11. Ash Content:
    • Ash content is the inorganic residue left after burning the filter paper. Lower ash content indicates purer material and is important in applications where the filtered substance needs to be ash-free.
  12. Strength and Durability:
    • Filter paper should have adequate mechanical strength to withstand handling and filtration pressure without tearing or disintegrating.
  13. Temperature Resistance:
    • Some applications require filter paper that can withstand high temperatures. This is particularly important in processes involving heat-sensitive samples.
  14. Acid/Base Resistance:
    • The filter paper should be resistant to chemical attack by acids or bases, especially in applications where the filtrate is chemically reactive.
  15. Sterility:
    • In certain applications, especially in microbiology and healthcare, sterility is crucial. Sterile filter papers are available for these purposes.
  16. Compliance with Standards:
    • Filter papers may need to meet specific industry or regulatory standards, especially in areas like pharmaceuticals, food, and environmental testing.

Remember, it’s important to select the appropriate grade and specification of filter paper based on the specific requirements of your filtration application. Always refer to the manufacturer’s recommendations for compatibility and usage instructions.

Filter paper New Size-Diameter of 750mm

Hawach Scientific Filter paper is made of cotton wool with an ash content of less than 0.006%. High alpha cellulose production under strictly controlled production conditions, to ensure batch quality year after year. After more than 15 years of production and promotion, our products have received very good feedback from the market, and we will keep going and let more and more clients use them.

In the past years, we used to provide the regular size such as 110mm, 125mm, 150mm, and 180mm, but different applications have some special use for production after the final testing, such as Qualitative filter paper when in the lab you can using 150mm filter paper, but in the real production, maybe you should be using 400mm, 500mm or 750mm.

Recently, we customized 750mm filter paper for our VIP Client; the big size saved his time and working efficiency. If you also need 750mm qualitative filter paper or a size less than 750mm, please don’t hesitate to contact us. We will do our best to support your work!

Normally, the residual ash remains a lot in the qualitative filter paper. Filter paper disc is only for ordinary qualitative analysis, sediment filtration, and solution for suspension. It cannot be used for quality analysis. When referring to the specification, the qualitative filter paper is almost the same as the quantitative filter paper. However, instead of belts with different colors, the words fast speed, intermediate speed, and low speed are printed on the filter paper boxes.

Furthermore, the quantitative filter paper is mainly used for an analysis experiment that needs ashing and weighing after filtration. The ash weight is a constant value after each filter paper is assigned. While qualitative filter paper is primarily used for ordinary filtration. So, the difference between the two kinds of filter papers mainly focuses on the ash weight after ashing.

Click here to know more about The Composition and Application of Filter Paper and Precautions When Using Qualitative and Quantitative Filter Paper.