PolyDADMAC, whose full name is polydimethyldiallylammonium chloride, is a cationic water-soluble polymer that is widely used in the field of water treatment. Due to its unique cationic charge density and high water solubility, PolyDADMAC is an efficient coagulant that can effectively remove turbidity, color and other impurities in water. However, in practical applications, it is often used as a flocculant in combination with other coagulants to treat industrial sewage.
Characteristics and mechanism of action of PolyDADMAC
PolyDADMAC rapidly adsorbs and aggregates negatively charged colloidal particles and suspended solids in water due to its high cationic charge density. Its mechanism of action is mainly based on electrostatic attraction, which causes these tiny particles to agglomerate into large particles, so that they can be effectively removed during subsequent precipitation or filtration processes.
The flocculation mechanism of PolyDADMAC
Flocculation is one of the steps in the coagulation process. It refers to the process in which the
" small alum flowers" formed during the coagulation process form flocs with larger particles through adsorption, electrical neutralization, bridging and net-capture.
In the water treatment industry, adsorption and electrical neutralization are classfied as coagulation, while bridging and net-capture are classifed as flocculation. The corresponding chemicals are called coagulants and flocculants respectively.
It is generally believed that PolyDADMAC has three mechanisms of action: adsorption, electrical neutralization and bridging. The first two are the main ones. That is why PolyDADMAC is classified as coagulants. However, most people regard coagulation and flocculation as the same process, so PolyDADMAC is also called a flocculant.
In water treatment processes, PolyDADMAC is mainly used as a flocculant to improve water quality. Specifically, the cationic quaternary ammonium salt group of PolyDADMAC can generate electrostatic attraction with anionic suspended particles or colloidal particles in the water, resulting in neutralization, forming flocs of larger particles and settling them. These flocs are screened out during the subsequent sedimentation or filtration process to purify the water quality.
Advantages of PolyDADMAC
Compared with traditional flocculants (alum, PAC, etc.), PolyDADMAC has the following significant advantages:
Efficient: PolyDADMAC can quickly remove impurities in water and improve water quality.
Easy to operate: Its use is simple, just add it under appropriate conditions.
Sustainability: PolyDADMAC has good stability and does not break down easily like polyacrylamide.
Strong flocculation effect: The cationic quaternary ammonium salt group gives PDMDAAC strong flocculation ability, thereby effectively treating various water qualities;
Good salt resistance, acid and alkali resistance: PDMDAAC is suitable for complex water quality conditions, and it still has stable flocculation performance under high salinity, acidic or alkaline conditions;
Low cost: PolyDADMAC has high flocculation efficiency and a low dosage, which can reduce water treatment costs.
Low sludge: PolyDADMAC produces less sludge than inorganic coagulants and flocculants and save post-processing costs.
PolyDADMAC dosage and precautions
When using PolyDADMAC, operating procedures should be strictly followed to ensure optimal treatment results and avoid possible side effects. Usually, after adding flocculants such as polyaluminium chloride, PolyDADMAC is added to achieve the best coagulation effect. In addition, the dosage should be appropriately adjusted according to water quality and treatment requirements. The suitable dosage could be determined by jar tests.
All in all, PolyDADMAC plays an important role in the field of water treatment. A deeper understanding of its properties and applications will help to more effectively use this product to improve water quality and protect the environment.
Post time: Nov-14-2024