What are the different types of polyelectrolytes?

According to their ionic charge, polyelectrolytes have been classified into four different categories. Cationic and anionic polyelectrolytes are more commonly used in water treatment. Polymers with no charged group are known as non-ionic polymers.

Are cationic polyelectrolytes used as coagulants?

According to literature, cationic polyelectrolytes have been most widely used as primary coagulants, however non-ionic and anionic polyelectrolytes are mostly used as flocculants (Bratby 2006). Different types of cationic polyelectrolytes are available commercially.

Why are cationic and anionic polyelectrolytes used in Water Process Engineering?

Generally speaking, cationic and anionic polyelectrolytes are chiefly used in water process engineering because of the electrostatic interaction or other association between the polyelectrolyte and contaminant. On the other hand, the application of polyampholytes is comparatively rare during water process engineering .

Which polyelectrolyte is used in water treatment?

Synthetic polyelectrolyte namely non-ionic PAM has also been used in water treatment (Selvapathy and Reddy 1992). It consists of 1–3% anionic group as in case of PAM, where they are prepared by hydrolysis of amide groups under controlled conditions.

Are polyampholytes useful for water treatment?

Literature review reveals that polyampholytes have very little utility for water treatment (Bratby 2006). According to literature, cationic polyelectrolytes have been most widely used as primary coagulants, however non-ionic and anionic polyelectrolytes are mostly used as flocculants (Bratby 2006).

What are water soluble polyelectrolytes?

In the simplest sense, water-soluble polyelectrolytes are polymers that contain charged disassociating monomer subunits. The charges can be pendant to the polymer chain or be part of the polymer chain itself. The overall charge of the polymer chain can be neutral (nonionic), positive (cationic), or negative (anionic).