Cationic Polyacrylamide
315
03/27/2025
1.Product Characteristics
1.1 Basic Properties and Physicochemical Characteristics
Chemical Name: Cationic Polyacrylamide (CPAM)
Chemical Structure: Polyacrylamide backbone combined with cationic groups (typically quaternary ammonium salts or tertiary amines)
Physical State:
- White or slightly yellow powder, granules, or emulsion
- Powder density approximately 0.6-0.8 g/cm³
- Highly hygroscopic, readily dissolves in water to form high-viscosity solutions
- Commercial products often supplied as emulsions with 20-50% solid content or powders with 90-95% solid content
Molecular Characterisitics
- Linear polymer
- Molecular weight typically ranges from 3 million to 18 million Daltons.
- Cationic charge density (ionicity) typically 10-70 mol%
- The structure contains functional groups such as -CONH₂, -CH₂N(CH₃)₃+
Solubility
- Completely soluble in water, solubility affected by molecular weight and ionicity.
- High molecular weight products dissolve more slowly, requiring 4-24 hours for complete dissolution
- Insoluble or slightly soluble in most organic solvents.
- 0.1-0.5% aqueous solutions have viscosity ranges between 100-5000mPa·s
Stability
- Stable at room temperature in a dry state.
- Aqueous solutions stable for approximately 30-90 days at room temperature.
- Stability decreases in strongly alkaline or acidic conditions (pH 10)
- Sensitive to shear, strong shearing leads to molecular chain breakage and reduced efficiency.
Shelf Life
- Powder form has shelf life of 1-2 years under dry conditions.
- Emulsion form typically has shelf life of 6 months to 1 year.
- Prepared solutions should be used within 7-14 days.
1.2 Performance Characteristics
- High Flocculation Efficiency
- Produces significant flocculation effects at extremely low dosages (typically 1-10 ppm), creating large and tightly structured flocs.
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- Rapid Settling Properties
- Promotes formation of settbleable flocs from suspended particles in water within short periods (typically 3-15 minutes).
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- Broad Sepctrum Adatability
- Effective flocculation for various negatively charged contaminants (such as organic matter, clay, silicates, etc)
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- Low Temperature Adaptability
- Maintains good flocculation effects in temperature ranges of 5-45°C, with some products suitable for use below 0°C.
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- Ionic Selectivity
- Not sensitive to multivalent metal ions (such as Ca²⁺, Mg²⁺ ), remains effective in high-hardness water.
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- Concentration Enhancement Effect
- Significantly improves sludge thickening ratio and dewatering performance, reducing sludge volume by 30-50%.
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- Flexible Dosage Adjustment
- Dosage can be adjusted within a wide range according to water quality characteristics and treatment requirements, offering great operational flexibility.
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- Good Synergy with other treatment agents
- Can be used in combination with inorganic flocculants (such as polyaluminum chloride), oxidants, and other water treatment chemicals.
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2.Mechanism of Action
2.1 Flocculation Mechanisms
2.1a Charge Neutralization
- Cationic groups neutralize surface charges of negatively charged particles in water.
- Reduces electronstatic repulsion between particles.
- Neutralization efficiency is directly related to polymer ionicity (typically 10-70%).
2.1b Polymer Bridging Effect
- Long chain molecules simultaneously adsorb multiple particles, forming "molecular bridges".
- Bridging effect positively correlated with molecular weight (3 million - 18 million).
- Floc structures formed are more stable and less prone to breakage.
2.1c Network Capture Effect
- Polymer chains form network structures.
- Physically capture fine particles.
- Particularly effective for colloids and fine particles (
2.1d Hydrophobic Association
- Some modified CPAMs contain hydrophobic groups.
- Enhance flocculation of organic contaminants through hydrophobic interactions.
- Particularly effective in oil-water separation applications.
2.2 Key Factors Affecting Flocculation Efficiency
2.2a Molecular Characteristic Factors
- Affects bridging capability and floc strength
- Affects charge neutralization capability and solubulity
- Linear structures typically provide better flocculation than branched structures.
2.2b Application Condition Factors
Dosage: optimal dosage window is typically narrow, overdosing can lead to restabilization.pH value: optimal range typically 6-9, extreme pH affects performance.Mixing intensity: requires appropriate initial mixing intensity (G value approximately 300-700 s⁻¹).Retention Time: typically requires 3-15 minutes for flocculation.2.2c Water Quality Factors
- Suspended solid characteristics
- Particle size, surface charge, and concentration
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- Water temperature
- Low temperatures (
- Ionic Strength
- Salt content in water affects polymer conformation and adsorption characteristics.
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- Interfering Substances
- Organic matter, surfactants, etc. Also can compete with CPAM for adsorption.
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3.Application Fields
3.1 Municipal Water Treatment
3.1a Drinking Water Treatment
- Used as a coagulant aid in coagulation/flocculation processes, typical dosage 0.2-1.0 ppm.
- Improves efficiency of conventional coagulants (such as alum).
- Reduces turbidity to
- Can reduce coagulant dosage by 20-40%.
3.1b Municipal Wastewater Treatment
- Secondary clarifier performance enhancement, improving SS removal by 10-25 percentage points.
- Used in activated sludge processes to improve sludge index (SVI).
- Typical dosage 0.5-3 ppm of wastewater flow.
- Can improve biological treatment system resistance to shock loads.
3.1c Sludge Treatment
- Sludge conditioning before dewatering, typical dosage 0.1-0.3% of dry sludge weight.
- Improves belt filter press and centrifuge dewatering efficiency.
- Can reduce sludge moisture content by 3-8 percentage points.
- Reduces sludge treatment operating costs by 15-30%.
3.1d Algae Control
- Flocculates blue-green algae in lakes and reservoirs.
- Typical dosage 0.5-2 ppm.
- Reduces risk of algal toxin release.
- Improves water body transparency
3.2 Industrial Water Treatment
3.2a Paper Industry
- Retention and drainage aid in pulp preparation, dosage 0.01-0.05% of dry pulp weight.
- Improves retention of fine fibers and fillers by 15-25%.
- Enhances paper strength and uniformity.
- Reduces suspended solids content in white water circulation systems.
3.2b Mining Applications
- Clarifier in mineral flotation processes.
- Flocculant in tailings treatment, dosage 30-100 g/t of solids.
- Improves solid-liquid separation efficiency.
- Promotes recovery of valuable minerals.
3.2c Petroleum Extraction
- Drilling mud treatment
- Oilfield injection water treatment to remove suspended solids
- Oil-water separation processes
- Typical dosage 1-5 ppm
3.2d Textile Dyeing and Printing
- Decolorization treatment of wastewater
- Suspended solids removal
- Combined use with inorganic coagulants to treat highly colored wastewater
- Dosage typically 5-20 ppm depending on wastewater characteristics
3.2e Metallurgical Industry
- Picking wastewater treatment
- Heavy metal wastewater treatment, promoting metal hydroxide precipitation
- Improves clarification efficiency
- Reduces suspended solids content in effluent
3.3 Emerging Application Fields
3.3a Soil Improvement
- Prevents soil erosion, improves soil stability
- Improves soil structure
- Enhances water retention capacity
- Dosage 0.001-0.01% of soil weight
3.3b Seawater Desalination Pretreatment
- Reduces reverse osmosis membrane fouling risk
- Removes natural organic matter from seawater
- Extends membrane life
- Reduces system operating costs
3.3c Biomass Energy
- Microalgae harvesting
- Solid-liquid separation in biofuel production processes
- Improves biomass concentration efficiency
- Reduces harvesting energy consumption
3.3d Aquaculture
- Aquaculture wastewater treatment
- Water quality improvement
- Reduces harmful algae proliferation
- Improves aquaculture environment stability
4.Selection and Usage Guidelines
4.1 Product Selection Criteria
4.1a Molecular Weight Selection
- High turbidity water (> 200 NTU)
Select medium molecular weight (8 million - 12 million) products
- Low turbidity water (
Select high molecular weight (> 12 million) products.
- Sludge dewatering
Select ultra-high molecular weight (> 15 million) products.
- Rapid settling requirement
Prioritize high molecular weight products
4.1b Ionicity Selection
- Low charge demand waters (such as river water): low ionicity (10-20%).
- Medium charge demand (such as municipal wastewater): medium ionicity (20-40%).
- High charge demand (such as paper mill wastewater): high ionicity (40%-70%).
- Sludge dewatering: typically select medium-high ionicity (30-50%) products.
4.1c Product Form Selection
- Large water plants: preferably powder products, lower cost
- Small and medium-scale applications: emulsion products dissolve more conveniently
- Automatic dosing systems: emulsion products more suitable for automatic metering.
- Remote area applications: solid products convenient for transportation and storage.
4.2 Usage Methods and Precautions
4.2a Solution Preparation
- Recommended concentration for solid products 0.1-0.5% (mass fraction).
- Emulsion products are typically diluted to 0.05-0.2% for use.
- Use mechancial stirring during preparation, control speed at 200-400rpm.
- Recommended dissolution water temperature 15-30°C, pH 6-8.
4.2b Dosing Point Selection
- Should does in well-mixed areas
- When used with inorganic coagulants, they should add with 1-3 minute intervals.
- Avoid direct dosing in high shear areas (such as pump outlets).
- Sufficient mixing time (30 seconds-2minutes) should exist between dosing point and coagulation zone.
4.2c Dosage Optimization
- Initial dosage typically 0.5-1ppm, then adjust according to effect.
- Use jar tests to determine optimal dosage.
- Overdosing can cause "charge reversal" and floc redispersion.
- Regularly adjust dosage based on influent water quality changes.
4.2d Monitoring Indicators
- Turbidity or suspended solids removal rate
- Floc formation time and floc characteristics
- Sludge settling performance(SVI)
- Filter cake moisture content (dewatering applications)
4.2e Common Problems and Solutions
- Incomplete dissolution
Extend dissolution time, improve stirring conditions, check water quality
- Poor flocculation
Check pH, adjust dosage, consider changing product type
- Rapid viscosity decrease
Avoid long-term solution storage, prevent microbial contamination
- Unstable performance
Check dosing system, increase mixing intensity, adjust dosing sequence

5.Industry Chain Analysis
5.1 Upstream Industry
- Main raw materials: acrylamide monomer, methylchloride ammonium, dimethylaminoethyl methacrylate, etc.
- Raw material suppliers: Sinopec, BASF, Mitsubishi Chemical, etc.
- Raw material costs account for 60-70% of product costs.
- Raw material prices are highly correlated with petrochemical product prices.
5.2 Core Production
- Main production processes: solution polymerization, inverse emulsion polymerization, radiation polymerization.
- Main equipment: reactors, dryers, grinding equipment, packaging equipment.
- Energy consumption: approximately 2-4 tons of standard coal per ton of product.
- Production cycle: batch production typically 8-24 hours.
5.3 Downstream Applications
- Municipal wastewater treatment accounts for 30-35% of total demand.
- Paper industry accounts for 20-25%.
- Mining and oil&gas account for 15-20%.
- Other industrial applications account for 20-25%.
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