7 Technical Parameters Helps You to Better Understand Filter Paper

The filter paper is not in close contact with the inner wall of the funnel, that is, there are bubbles between the filter and the inner wall, which will seriously affect the filtration speed. If the glass rod is not used for drainage, it will cause the filtrate to be splashed and affect the experimental results.
There are two main reasons why the filter paper sticks to the inner wall of the funnel:

1. If it is not close to the inner wall of the funnel, it is easy to produce bubbles, which will slow down the filtration speed and lengthen the experiment time.
2. If it is not close to the inner wall of the funnel, there will be gaps left, and some parts will not be able to be filtered. So it will affect the effect of the experiment.
Most filter papers are made of cotton fibers, which are made by different methods for different purposes. Because its material is made of fiber, there are countless small holes on its surface for liquid particles to pass through, but larger solid particles cannot pass through. Therefore, it is better to select high-quality products. Such as 10 micron filter paper, 20 micron filter paper.

HAWACH filter paper is of superior quality in this respect, which is shown in 1.

It is produced with high-purity α-cellulose and cotton fiber, and the product has low ash content, that is, low background value and impurities dissolve out low rate;
2. HAWACH has strict quality control links, so the quality stability of the unified batch and different batches of filter paper is high;
3. HAWACH can provide safety test report certification.

Today, HAWACH will discuss 7 parameters for a better understanding of the filter paper.

A. Pore size: The filter paper is different from the filter membrane with accurate size. The filter paper has no precise pore size, just a rough value.

B. Flow rate: The flow rate is mainly affected by the aperture, the larger the aperture, the faster the flow rate. There are three current flow rates: fast, medium, and slow.

C. Ash content: It refers to the residual ash content of the filter media after burning in the air at 900 degrees. Ash content is very important for gravimetric experiments. The smaller the ash content of the filter medium, the lower the impurity background, which also helps to judge the cleanliness of conventional samples. The essential difference between qualitative filter paper and quantitative filter paper lies in the ash content. Qualitative filter paper ash content: <0.1%, quantitative filter paper <0.007%.

D. Gram weight: It refers to the weight of the product per square meter. Qualitative filter paper: 80+/- 4, while it can actually reach about 82g. Quantitative filter paper: 97+/-7, while it can actually reach about 101. All of the HAWACH filter papers are with better performance than ordinary quantitative filter papers.

E. Wet burst resistance: It refers to the uniformly increased maximum vertical pressure that the paper or cardboard can withstand per unit area. HAWACH uses mm water column to express it.

F. Size: there are round, square, and irregular shapes. For round filter paper, the conventional specifications include 70, 90, 10, 125, 150, 180 and unconventional ones include 240,270, 300. For the square filter paper, there are 60×60 and 41×45. Also, HAWACH filter papers can be customized based on customer requirements.

G: Impurity dissolution rate (usually called blank sample background value): Generally, quantitative filter paper is used in the laboratory to collect experimental samples, and the sample is analyzed after pre-processing together with the experimental samples. If the filter paper itself is introduced in the pre-processing process Impurities cause pollution to customer samples.

Please click here to know Which filter paper is used in gravimetric analysis.