Polyacrylamide is referred to as PAM, flocculant No. 3 or coagulant; polyacrylamide is divided into anionic polyacrylamide, cationic polyacrylamide, nonionic polyacrylamide, zwitterionic polyacrylamide; product appearance is white or slightly yellow powder (Figure 1). Molecular weight between 400-1800 million, polyacrylamide molecules with a positive group (-CONH2), with the dispersion of suspended solids in the solution, adsorption and bridging, has a strong flocculation, it is widely used in water Processing and metallurgy, paper, petroleum, chemical, textile, mineral processing and other fields.
1, flocculation. PAM can make the suspended material through the electrical neutralization, play a role in flocculation;
2, thickener. In the neutral and acidic conditions have a thickening effect, if the PH value of 10 or more PAM easy hydrolysis;
3, adhesion. Can play a role by physical chemical action.
4, drop resistance: PAM can effectively reduce the friction of the fluid, the water can be reduced by adding trace PAM 50-80%.
PAM for sewage treatment, the removal of organic matter in water, high efficiency, low dosage, fast settling, water production costs are low, other flocculants can not replace the product.
1, PAM for flocculation, and floc type of surface properties, in particular, the potential, viscosity, turbidity and the PH value of the suspension, the particle surface of the dynamic potential is the reason for the addition of particles added to the surface charge of the opposite PAM, can make the potential lower and cohesion.
2, PAM molecular chain is fixed on the surface of different particles, the particles formed between the polymer bridge, so that particles formed aggregates and sedimentation.
3, PAM molecules on the polar groups of particles of various adsorption.
4, enhance the role: PAM molecular chain and dispersed phase through a variety of mechanical, physical, chemical and other effects, the dispersed phase implicated together to form a network.
Cationic molecular weight is high, mainly for the suspension of water suspensions and suspensions, acidic and acidic solution containing organic suspension when the flocculation is very difficult. In this case, the cationic polyacrylamide is effective in flocculating and exhibiting its outstanding properties. The use of 0.1-0.2% form of aqueous solution, must be Ph ≤ 7 water preparation, dubbed dilute solution easily hydrolyzed. Should be with the use or in the day run out, not a long time storage.
Anionic type is mainly used for domestic production of water, industrial and urban sewage treatment. It is also suitable for the flocculation and sedimentation of red mud during the preparation of alumina.