Why does cationic polyelectrolyte have a maximum ZP?

The maximum ZP appeared at pH level of 4.0–5.0 because of the characteristics of cationic polyelectrolyte. Under acidic conditions, the ionization of quaternary ammonium salts in DMC was heavily promoted by numerous hydrogen ions, and amide groups NH 2 in AM was converted to NH 3+ through protonation .

How cationic polyacrylamide (PAMC) is prepared?

Flocculation and mechanism was discussed based on zeta potential and pH analysis. A novel cationic polyacrylamide (PAMC) with various cationic monomer contents were prepared by copolymerizing acrylamide (AM) and methacryloxyethyl trimethyl ammonium chloride aqueous solution (DMC) through low-pressure ultraviolet (UV) initiation.

What is anionic polyacrylamide (Apam)?

1. Introduction Anionic polyacrylamide (APAM) is a kind of organic high-molecular polymer with high hydrophilicity and viscosity, which is easily dissolved in water [, , ].

Does cationic monomer content affect the optimal transmittance of Pam?

The optimal transmittance of 11.21% with PAM was achieved at dosage of 1.0 mg·L −1. The results also suggested that the removal efficiency was improved significantly, and the optimal dosage decreased evidently as cationic monomer content in PAMC increased. A few differences emerged under neutral environment (pH = 7.0) as illustrated in Fig. 5 (b).

How effective is PAMC flocculation in turbid water clarification?

Chemical and morphology structures of PAMC were characterized and analyzed. Flocculation performance and kinetics were investigated in highly turbid water clarification. Most effective flocculation occurred at pH 4 with the flocculant which contained the highest cationic content.

Does polyacrylamide hydrolyze under acidic conditions?

As reported by Muller et al., polyacrylamides undergo hydrolysis under acidic conditions to yield poly (acrylamide-co-acrylic acid). Amide groups will completely hydrolyze under conditions of appropriately low pH, and polymer weight will remain relatively stable during hydrolysis, as the following formula , , .