When using flocculants alone could not achieve the expected effect, it is needs to add some auxiliary agent to improve effects, this agent is called coagulant. Generally speaking, any chemical agent which cannot be used solely as coagulant in a certain water treatment process but can be used in conjunction with coagulant to improve the coagulation and flocculation effect can be called coagulant aid. Coagulation aids can be used to adjust or improve coagulation conditions, such as adding lime or sodium bicarbonate when the alkalinity of raw water is insufficient, and adding oxygen to oxidize ferrous Fe2+ to ferric ion Fe3+ when ferrous sulfate is used as coagulant. The flocculants can also be used to improve the structure of flocculants. The strong adsorption and bridging effect of macromolecule flocculants can make the fine and loose flocculate coarser and tighter.
PolyDADMAC with a molecular formula of (C8H16NCl)n, is a strong cationic polyelectrolyte, with the appearance of colorless to pale yellow viscous liquid. It is safe, non-toxic, soluble in water, nonflammable, strong cohesion, good hydrolysis stability, no gel, insensitive to changes in pH value, and has chlorine resistance. It is used as a cationic coagulant in sewage treatment, mining and mineral processing. It can be used as an excellent formaldehyde free fixing agent in textile industry to form film on fabric and improve its color fastness. It is used as formaldehyde-free fixing agent, anionic garbage trapping agent and AKD ripening accelerator in papermaking process, clay stabilizer for drilling and acidizing fracturing cationic modifier for water injection in oilfield industry. In addition, they are also used as modulators, antistatic agents, humidifiers, shampoos and emollients for skin care. It can be used as retention and filter aid and antistatic agent for paper coating; it can be used for decolorization, flocculation and purification in the process of water treatment, high efficiency and non-toxic; in daily chemicals, it can be used as carding agent, wetting agent and antistatic agent for shampoo; in oilfield chemicals, it can be used as flocculants, water plugging agent, etc. Its main function is electric neutralization, adsorption, flocculation, purification, decolorization, especially as a synthetic resin modifier, giving conductivity, antistatic.
When application, the polydadmac coagulant needs be diluted firstly and then added directly to the water to be treated, stirred, precipitated and filtered. It can also be combined with poly aluminum for various water treatment applications.
