Made of interwoven fibers, no matter plant fibers or other various fibers with many small holes, the laboratory filter paper has good permeability for gas and liquid. The filter paper has the basic structure of cotton fibers made with cellulose, among other materials, working as a physical barrier and separating solid or semi-solid particles substances at a fast, intermediate, or low speed according to the type of paper used.
In addition to the above-mentioned mixed fibers, some fillers must be added according to the formula, such as titanium dioxide, perlite, activated carbon, diatomaceous earth, ion exchange resin, etc. For special papers, it should be processed several times, for instance, to be sprayed, or impregnated, and also can be linked with other materials (such as non-woven fabrics, chemical fiber cloth, etc.) to improve other filter material properties.
Because of laboratory filter paper made of cotton fibers made with cellulose, among other materials, in the process of filtration, the filter pores will be clogged by retained solid particles when the pore is smaller than particles. In this way, the filtration capacity of the laboratory filter paper is greater, as the number of pores is greater. On the other side, the pores on the filter have different degrees of porosity and different pore sizes. when the number of pores is greater and the pole size is larger, the filtration efficiency will be higher.
Regarded as inert support, the filter paper is resistant to lots of chemical reactions without any impurities generated. To improve the hardness or mechanical resistance to humidity, some chemical stabilizer is added to the base structure of the filter paper. When the hardness is higher, the quality of the filter paper is higher as while the deformation or deterioration of the paper is less.
Filter paper disc round in common and square sometimes, also have filter paper roll, the laboratory filter paper is an essential tool in a modern lab. Besides working as a mechanical filter barrier, the filter paper can be used as inert support in qualitative techniques, where the scientists separate and identify the organic and inorganic substances in chromatography and electrophoresis. It is also used as a quantitative technique in gravimetric analysis.
It has been applied to many industries. The filter paper chooses all plant fibers as its raw materials, for instance, mulberry pulp, cotton pulp, chemical wood pulp, and so on. Some are glass fiber, synthetic fiber, aluminum silicate fiber, even metal fibers. There is thick and thin paper and it’s easy to process the shape. Also, they are easy to cut and fold. Also, it’s more cost-effective to produce, transport, and store it. It plays an important role in decolorization, deodorization, separation, purification, concentration, recycling, etc. It also plays important role in resource-saving, equipment maintenance, and environmental protection.
Qualitative vs Quantitative Filter Paper
In chemical experiment classes in schools or chemical analysis in factories, the more commonly used chemical analysis filter papers are divided into two types: one is called qualitative filter paper, and the other is called quantitative filter paper. The quantitative of qualitative filter paper is 80g/m2, divided into three types according to the filtration speed: fast (not more than 30s per 100ml), medium speed (not more than 60s per 100ml), and slow (not more than 120s per 100ml).
Usually, there are 100 sheets of qualitative filter paper in each box, and there is a ribbon mark on the box. It’s difficult to distinguish between the quantitative filter paper and qualitative filter paper just from the appearance. But it has higher quality with less than 0.01% ash content left so that filter weight can be accurately obtained during analysis and measurement without causing errors. Due to it, use other technological measures (such as mixed acid treatment, ion exchange, etc.) to ensure the quality of the finished paper during the quantitative filter paper-making process. In the same way, quantitative filter paper is also divided into fast, medium, and slow speed.