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How do you choose the right polyacrylamide (PAM) for wastewater treatment? Both anionic PAM (APAM) and cationic PAM (CPAM) are widely used flocculants, but they differ in mechanism, molecular structure, and application fields.
Choosing the wrong type can lead to poor treatment performance, increased chemical consumption, and higher operational costs. Anionic PAM is best for wastewater with large suspended particles, while cationic PAM is more effective for organic wastewater and sludge dewatering.
This article will compare APAM and CPAM in detail, highlight their differences, and guide you on how to select the right type for your industry!
Anionic PAM vs. Cationic PAM: Key Differences
| Feature | Anionic PAM (APAM) | Cationic PAM (CPAM) |
| Molecular Weight | 8–25 million | 8–12 million |
| Main Indicators | Molecular weight, hydrolysis degree (low 5-15, medium 23-27, high 28-35) | Ionic charge (5-70%, higher charge = better treatment efficiency) |
| Dissolution Time | ≤30 minutes | ≤60 minutes |
| Cost | Lower | Higher |
| Best pH Range | Neutral or alkaline wastewater | Acidic or alkaline wastewater |
| Best for | Large suspended particles, inorganic pollutants | Organic wastewater, sludge dewatering |
Main Applications of Anionic PAM (APAM)
🔹 1. Industrial Wastewater Treatment
✔ Best for wastewater with large suspended particles, high concentration, and positive charge.
✔ Used in steel plants, electroplating plants, metallurgical wastewater, and coal washing wastewater.
🔹 2. Drinking Water Purification
✔ Used in river water treatment, where sediment and minerals cause turbidity.
✔ Works well with inorganic coagulants for better results.
🔹 3. Starch & Alcohol Industry – Solid-Liquid Separation
✔ Helps recover starch particles from wastewater, turning them into feed material.
✔ In alcohol production, APAM aids in dewatering and filtration for efficient recovery.
🔹 4. Oilfield Applications
✔ Used in oil extraction, drilling mud treatment, and enhanced oil recovery (EOR).
🔹 5. Papermaking Additive
✔ Improves filler and pigment retention, reducing material loss and pollution.
🔹 6. Textile & Printing Industry
✔ Used as a textile sizing agent, improving fabric smoothness and reducing breakage.
🔹 7. Adhesive Agent
✔ Commonly used in incense production, enhancing strength and appearance.
Main Applications of Cationic PAM (CPAM)
🔹 1. Sludge Dewatering (Most Common Use)
✔ Ideal for sludge dewatering in pharmaceuticals, food processing, chemicals, and papermaking.
✔ Improves filter press efficiency and reduces sludge moisture content (below 80%).
🔹 2. Organic Wastewater Treatment
✔ Best for negatively charged organic wastewater, such as:Alcohol, beer, monosodium glutamate (MSG), sugar, meat processing, textile dyeing wastewater.
✔ Far more effective than anionic PAM or inorganic coagulants.
🔹 3. Drinking Water Treatment in Municipal Water Plants
✔ Used as a flocculant, requiring low dosage but providing excellent results.
✔ Works best when combined with inorganic coagulants (e.g., PAC).
How to Choose the Right PAM?
| Wastewater Type | Recommended PAM | Dosage (mg/L) |
| Large suspended particles, neutral or alkaline wastewater | Anionic PAM (APAM) | 1-10 |
| Negatively charged organic wastewater | Cationic PAM (CPAM) | 2-10 |
| Sludge Dewatering | Cationic PAM (CPAM) | 10-20 |
| Drinking Water Purification | Anionic PAM + Inorganic Coagulant | 1-5 |
| Papermaking Additive | Anionic PAM (APAM) | 1-8 |
| Food & Pharmaceutical Wastewater | Cationic PAM (CPAM) | 5-15 |
🚀 Selection Tips:
🔹 For organic pollutants, use cationic PAM (CPAM); for inorganic pollutants, use anionic PAM (APAM).
🔹 For sludge dewatering, always use CPAM to improve efficiency and lower sludge moisture content.
🔹 Choose the appropriate PAM type based on pH level to avoid flocculation failure.
Conclusion: Choose the Right PAM for Better Wastewater Treatment!
✅ Anionic PAM (APAM) is best for large suspended particles and inorganic wastewater, such as steel, coal washing, and electroplating industries.
✅ Cationic PAM (CPAM) is ideal for organic wastewater and sludge dewatering, including food, pharmaceuticals, and textile industries.
✅ Using the correct PAM type and dosage ensures better flocculation, faster sedimentation, and cost-effective wastewater treatment!
🚀 Shandong Hychron EnergyTech Co.,Ltd. has been specializing in wastewater treatment for 20 years, providing customized PAM solutions to help businesses reduce costs and improve compliance rates!
📩 Contact us today for the best PAM products and expert technical support!
