Acrylamide emulsions are prepared by dispersion or reverse-phase emulsion polymerization and are a form of polyacrylamide liquid. In addition to the properties of solid polyacrylamide flocculants, suspended solids in water particles are adsorbed by polar groups on the molecular chain, and emulsions can form large flocs by cross-bridging between particles or electrically.
Polyacrylamide emulsions are divided into water-in-oil and water-in-water types. Unlike PAM powders, the production of emulsion PAM powders does not require a drying process. Therefore, the molecular weight and water solubility of polyacrylamide emulsions are higher than that of the same powdered polyacrylamide. Water-in-oil emulsions are usually insoluble in water. Therefore, during the manufacturing process of emulsified polyacrylamide, or the dissolution and dilution process before using emulsions, hydrophilic surfactants need to be added so that the emulsions are water-soluble when reversed by water. However, water-in-water emulsions are very easy to dissolve, and the synthesis process is more advanced.
When the emulsion is dissolved with water, high-speed shear should make the polyacrylamide hydrogel emulsion fully contact with water and quickly disperse in water. If the emulsion is fully dispersed in contact with water, the dissolution time is generally only 3-15 minutes. The emulsion's storage temperature should preferably be between 0~30℃, and the general storage time of the emulsion is 6 months. The temperature at which the emulsion is frozen is lower than the temperature of the water. After thawing, the frozen emulsion can be used without any significant change in its properties. Granular polyacrylamide is a polymerized colloid made from AM (acrylamide) monomer, crushed, and dried. There are too many disadvantages for polyacrylamide powder, too much dust, breakage of the molecular chain after crushing, and dissolution by stirring after drying (a waste of time and energy consumption). Still, the largest particle size of polyacrylamide is easy to transport and store.
In addition to solid polyacrylamide advantages, emulsion flocculants have their own advantages, such as a wide choice of charge density, fast dissolution speed, low energy consumption, and easy storage and use. Compared to traditional cationic polyacrylamide products, polyacrylamide emulsions offer a range of advantages, such as a wider pH range, higher charge stability, better flocculation, and lower dosage. It is also suitable for construction sites where large dissolution devices are not installed.
PAM emulsions are widely used in domestic wastewater, chemical wastewater, oilfield wastewater, sludge dewatering, paper making, and other industries. PAM emulsions are also widely used in urban sewage treatment, breweries, starch plants, food processing plants, and other wastewater treatment. It is particularly suitable for the flocculation of organic suspended solids in acid and acidic wastewater. The paper industry can be used as an auxiliary retention filter and paper wastewater treatment. The petroleum industry can be used as a coating agent or degreasing agent for drilling fluid.