Cationic polyacrylamide

The working principle of cationic polyacrylamide mainly includes charge neutralization, adsorption bridging, and mesh trapping and sweeping, as follows:

1. Charge neutralization: Cationic polyacrylamide molecular chains contain a large number of positively charged groups, such as quaternary ammonium salt groups. In the process of water treatment, colloidal particles in water usually carry negative charges. Due to electrostatic attraction, the positive charges on the cationic polyacrylamide molecular chains attract the negative charges on the surface of the colloidal particles, neutralizing the charges on the surface of the colloidal particles. In this way, the electrostatic repulsion between colloidal particles is significantly reduced, and colloidal particles that were originally stably dispersed in water due to charge repulsion can approach each other, creating conditions for aggregation.

2. Adsorption bridging: Cationic polyacrylamide has long molecular chains and a large specific surface area, and the active groups on its molecular chains can be adsorbed on the surfaces of colloidal and suspended particles. A cationic polyacrylamide molecule can simultaneously adsorb multiple particles, and through the stretching and bridging of molecular chains, connect multiple particles together to form larger flocs. As the flocs continue to grow, their settling speed accelerates, thus achieving solid-liquid separation.

3. Net capture and sweeping: When the amount of cationic polyacrylamide added is large enough, a large number of flocs produced by hydrolysis interweave with each other to form large flocs with a three-dimensional network structure. This mesh structure can capture and sweep suspended particles, colloidal particles, and other small impurities around it like a sieve during the settling process, allowing them to settle to the bottom of the water along with flocs, achieving the goal of purifying water quality.