Polyacrylamide (PAM) Introduction
Polyacrylamide (PAM) Introduction
Polyacrylamide (PAM) is a linear water-soluble polymer and a commonly used water treatment agent in our sewage treatment. In our actual
application, PAM is divided into three types: cationic, anionic and nonionic. How to choose these three types of PAM should start from the
difference between them.
I. Structural difference:
Cationic polyacrylamide (CPAM): It is a linear polymer compound. Because it has a variety of active groups, it can be affinity and adsorbed with
many substances to form hydrogen bonds. It is mainly used to flocculate negatively charged colloids.
Anionic polyacrylamide (APAM): It is a water-soluble polymer. It is mainly used for flocculation and sedimentation of various industrial wastewaters,
sedimentation and clarification treatment, such as steel plant wastewater, electroplating plant wastewater, metallurgical wastewater, coal washing
wastewater and other sewage treatment, sludge dehydration, etc. It can also be used for drinking water clarification and purification.
Because its molecular chain contains a certain number of polar groups, it can absorb solid particles suspended in water, bridge particles or form
large flocs by charge neutralization, so it can accelerate the sedimentation of particles in the suspension, and has a very obvious effect of
accelerating solution clarification and promoting filtration.
Non-ionic polyacrylamide (NPAM): It is a high molecular polymer or polyelectrolyte. Its molecular chain contains a certain amount of polar genes
that can absorb solid particles suspended in water, bridge particles to form large flocs. It accelerates the sedimentation of particles in the
suspension, and has a very obvious effect of accelerating solution clarification and promoting filtration. Because the molecular chain contains
amide groups or ionic genes, its significant feature is high hydrophilicity and can be dissolved in water in various proportions.
Polyacrylamide aqueous solution has good tolerance to electrolytes, such as ammonium chloride, sodium sulfate, etc.
It is also compatible with surfactants.
II. Differences in use:
1. Uses of non-ionic polyacrylamide
Sewage treatment agent: When the suspended sewage is acidic, it is more appropriate to use non-ionic polyacrylamide as a flocculant.
This is because PAM plays an adsorption and bridging role, causing suspended particles to flocculate and precipitate, achieving the purpose
of purifying sewage. It can also be used to purify tap water, especially when used in combination with inorganic flocculants, and has a good
effect in water treatment.
Textile industry auxiliaries: Adding some chemicals can make chemical materials for sizing textiles.
Sand control and sand fixation: Dissolve non-ionic polyacrylamide into a 0.3% concentration and add a cross-linking agent, and spray it on the
desert to prevent and fix sand.
Soil moisturizer: Used as a soil moisturizer and the basic raw material for various modified polyacrylamides.
2. Uses of cationic polyacrylamide:
Sludge dehydration: According to the nature of the sewage, the corresponding model of this product can be selected, which can effectively
perform gravity sludge dehydration before the sludge enters the filter press. During dehydration, large flocs are produced, which do not stick to
the filter cloth and do not disperse during filter pressing. The dosage is small, the dehydration efficiency is high, and the moisture content of the
mud cake is below 80%.
Treatment of sewage and organic wastewater: This product is positively charged in acidic or alkaline media, so it is extremely effective to flocculate
and precipitate the suspended particles in the sewage with negative charges, such as alcohol factory wastewater, brewery wastewater, monosodium
glutamate factory wastewater, sugar factory wastewater, meat food factory wastewater, beverage factory wastewater, textile printing and dyeing
factory wastewater, etc. The effect of using cationic polyacrylamide is several times or dozens of times higher than that of using anionic
polyacrylamide, nonionic polyacrylamide or inorganic salt, because this type of wastewater generally carries negative charges.
Water treatment flocculant for water plant: This product has the characteristics of small dosage, good effect and low cost, and the effect is better
when used in combination with inorganic flocculants.
Oilfield chemicals: such as clay anti-swelling agent, thickener for oilfield acidification, etc.
Papermaking additives: Cationic PAM paper enhancer is a water-soluble cationic polymer containing carbamoyl, which has the functions of
enhancement, retention and filtration, and can effectively improve the strength of paper. At the same time, this product is also a highly efficient
dispersant.
3. Uses of anionic polyacrylamide
Industrial wastewater treatment: For suspended particles, high concentration, positively charged particles, neutral or alkaline PH value of water,
steel plant wastewater, electroplating plant wastewater, metallurgical wastewater, coal washing wastewater and other wastewater treatment,
the effect is good.
Drinking water treatment: The water sources of many water plants in my country come from rivers, with high sediment and mineral content,
and are relatively turbid. Although they have been precipitated and filtered, they still cannot meet the requirements. Flocculants need to be added.
The amount of addition is 1/50 of that of inorganic flocculants, but the effect is several times that of inorganic flocculants. For river water with
serious organic pollution, inorganic flocculants and cationic polyacrylamide can be used together for better results.
Recovery of lost starch grains from starch plants and alcohol plants: Many wastewater from starch plants contain a lot of starch.
Anionic polyacrylamide is now added to flocculate and precipitate starch particles. The precipitate is then filtered through a filter press to
become a cake, which can be used as feed. The alcohol from the alcohol plant can also be dehydrated with anionic polyacrylamide and
recovered by filtering.
