Introduction
Anionic polyacrylamide (APAM) is a water-soluble polymer, the appearance is white powder, molecular weight from 6 million to 25 million water-soluble, can be dissolved in water in any proportion and insoluble in organic solvents. PH value of the effective range of 7 to 14 in the neutral alkaline media, in the characteristics of the high polymer electrolyte, and the electrolyte salt sensitive, with high metal ion can be cross-linked into an insoluble gel. Mainly used for a variety of industrial wastewater flocculation, sedimentation and clarification treatment, such as iron and steel plant wastewater, electroplating wastewater, wastewater metallurgy, coal washing wastewater treatment, sludge dewatering. It can also be used for drinking water clarification and purification. Because of its molecular chain containing a certain amount of polar groups, which can by adsorption of solid particles suspended in water, or bridging between the particles and the particles through the charge in the large flocs formed cohesion, it can accelerate the particles in suspension settlement, there are very significant to accelerate the solution is clear, and promote filtering effect.
Development history
Pharmaceutical compounds according to the type of flocculant can be divided into inorganic flocculants, organic polymer flocculant, microorganic flocculantand mineralflocculant these four categories, flocculant according to the nature of its charge after ionization can be subdivided into anionic, cationic, nonionic and amphoteric flocculants.
In the 1950s, the polymer flocculant began to grow, initially in industrial process applications, such as for concentrated mineral slurries. 1960s, environmental issues began to become a social problem, anionic and non-ionic polyacrylamide flocculating started for wastewater treatment. In the 70s, people use anionic polyacrylamide flocculant asdehydrating agent to deal with wastewater.
In recent years, industrial development and improving the quality of human life, industrial wastewater and domestic sewage pollution of the environment increasingly serious and environmental problems gradually warming up, flocculant in industrial and domestic wastewater applications are increasingly widespread. Spreading former sewage directly or simply mechanical and biological treatment, and now, flocculant water treatment technology development and the improvement of flocculation method has been successfully applied. In the current water treatment industry, flocculation sedimentation is an important and indispensable part, but some even replaced the biological treatment.
The traditional use of flocculants are low moleculeinorganic salt, due to its large feeding amount, produce large amounts of sediment flocculation and coagulation effect is not ideal, gradually being replaced by polymer flocculant. Polymer flocculant not only has good adsorption capacity, and can bridge adsorption. Polymer flocculants are aluminum chloride and other inorganic polymer flocculant, an organic polymer such as polyacrylamide flocculants in industrial water treatment process in order to save costs often use two or more kinds of flocculants use, but also get a good flocculation effect.