PAM Tech Indicators for WW Treatment

Main Technical Indicators of PAM in Wastewater Treatment:
The key technical indicators of polyacrylamide (PAM) include molecular weight, hydrolysis degree, ionicity, viscosity, and residual monomer content. These factors determine the quality of PAM:

1. Molecular Weight 
Polyacrylamide (PAM), with a high molecular weight, has seen significant increases in recent years. In the 1970s, PAMs had a molecular weight of several million; however, most advanced PAMs since the 1980s have a molecular weight over 15 million, some even reaching 20 million. Each PAM molecule is composed of more than one hundred thousand acrylamide or sodium acrylate molecules.
The molecular weight of PAM polymers varies within a product, with the nominal value representing an average. This is the most commonly heard indicator.

2. Hydrolysis Degree and Ionicity
The ionicity of PAM significantly impacts its performance but requires specific values depending on the type and properties of the treated material. High ionic strength materials require higher PAM ionicity, while lower ionic strength materials require lower PAM ionicity. Generally, the anionicity is known as the hydrolysis degree, and the cationicity is specifically referred to.

3. Residual Monomer Content
Residual monomer content refers to the amount of unreacted acrylamide monomers left in the PAM product during polymerization. It's crucial for food industry applications. While PAM itself is nontoxic, acrylamide can be toxic. Therefore, it's important to strictly control the residual monomer content in PAM products. The international standard for drinking water and food industries stipulates that the residual monomer content should not exceed 0.05%. Well-known foreign products typically have this value below 0.03%.

4. Viscosity
Polyacrylamide (PAM) solutions can be quite viscous, with higher molecular weight PAMs having greater viscosity due to their long, thin chain structure. Viscosity essentially reflects the internal friction of the solution, also known as the internal friction coefficient. All polymer organic solutions are relatively viscous and increase with increasing molecular weight. A method to measure the molecular weight of macromolecular organic substances is by determining the viscosity of a certain concentration solution under certain conditions, then calculating the molecular weight using a specific formula, called "viscous average molecular weight".