PAC (Polyaluminum Chloride): Properties, Applications & Price Quotes for 2025
Summary: PAC (Poly aluminum chloride) is the leading flocculant in water treatment. A comprehensive A-to-Z guide: definition, properties, mechanism of action, product forms, cross-industry applications, comparison with aluminum sulfate and FeCl₃, purchasing guide, and pricing. Updated 2025.
Table of Contents
- What is PAC?
- Properties & Flocculation Mechanism
- Types of PAC on the Market
- Applications of PAC
- Comparison of PAC vs. Aluminum Sulfate vs. FeCl₃
- Purchasing Guide & Price Quotes
- FAQ — 5 Frequently Asked Questions
1. What is PAC?
1.1. Definition
PAC (Poly Aluminum Chloride) — also known as Polyaluminum Chloride, PACl, or Polyaluminum Chloride — is an inorganic compound belonging to the group of polymerized aluminum salts, widely used as a coagulant in water treatment.
General chemical formula:
[Al(OH)ₐCl_b]_n where a + b = 3, 1 ≤ n ≤ 5Unlike traditional aluminum sulfate (Al₂(SO₄)₃), PAC has a polymeric structure with multiple aluminum atoms linked via oxygen (—O—) and hydroxyl (—OH—) bridges. This structure gives PAC a higher active aluminum content and superior flocculation efficiency.
1.2. Basic Technical Specifications
| Parameter | Value |
|---|---|
| CAS Number | 1327-41-9 |
| General Formula | Alₙ(OH)ₘCl₃ₙ₋ₘ |
| Al₂O₃ Content | 10–30% (depending on form) |
| Density (10% solution) | 1.18 – 1.22 g/mL |
| Basicity | 40 – 85% |
| pH of 1% solution | 3.5 – 5.0 |
| Solubility in water | Completely soluble |
| Color | White, pale yellow to yellow-brown (depending on form) |
1.3. Development History
PAC was developed in the 1970s in Japan as an alternative to aluminum sulfate, with the aim of overcoming its drawbacks: poor effectiveness at low temperatures, a narrow operating pH range, and high sludge production. Today, PAC has become the most widely used coagulant in the global water treatment industry.
2. Properties & Coagulation Mechanism
2.1. Physical Properties
- White powder form: Fine particles, dissolves rapidly in water, forming a clear to slightly cloudy solution
- Yellow powder form: Fine particles to flake-like particles, pale yellow to yellow-brown in color (due to iron impurities), dissolves rapidly
- 10% liquid form: Pale yellow to light brown solution, specific gravity ~1.20 g/mL, ready to use without dilution
2.2. Chemical Properties
- Weak acidity: PAC solutions have a pH of 3.5–5.0 → causing a slight decrease in water pH after dosing (though significantly less than aluminum sulfate)
- Basicity: The higher the basicity, the less alkali is consumed from the water, resulting in a smaller reduction in pH
- Stability: PAC is stable in solution and does not hydrolyze as rapidly as free Al³⁺
- Compatibility: Performs well over a wide pH range (5.0–9.0), with optimal performance at pH 6.5–7.5
2.3. Flocculation Mechanism
The flocculation mechanism of PAC is more complex than that of aluminum sulfate due to its polymer structure. There are three main mechanisms operating simultaneously:
a) Charge Neutralization
In water, colloidal particles (sludge, clay, organic matter, etc.) typically carry a negative charge, repel one another, and do not settle. When dissolved, PAC releases highly positively charged aluminum polymer complexes:
[Alₙ(OH)ₘ]⁽³ⁿ⁻ᵐ⁾⁺ + Colloidal Particle (−) → Neutralization → FlocculationThese polymer complexes have a much higher positive charge density than Al³⁺ from aluminum sulfate → stronger neutralizing ability, requiring a lower dosage.
b) Bridging Mechanism
PAC molecules have a long polymer chain structure, allowing a single PAC molecule to bind to multiple colloidal particles simultaneously, forming large, stable flocs:
PAC—Particle A—PAC—Particle B—PAC—Particle C → Large flocsThis mechanism is particularly effective for water with high turbidity and high TSS.
c) Sweep Coagulation Mechanism
At higher dosages, PAC forms Al(OH)₃ precipitates in the form of snowflake-like flocs. These Al(OH)₃ flocs “sweep” and carry suspended particles along as they settle.
2.4. Advantages Over Traditional Flocculants
- Dosage is 30–50% lower than aluminum sulfate to achieve the same effectiveness
- Less reduction in water pH → reduced or no need for alkali addition (NaOH, Ca(OH)₂)
- Less affected by temperature → stable performance even in cold weather
- Forms large, firm flocs that settle quickly → reduces retention time in the sedimentation tank
- 30–50% less sludge generated → reduced sludge treatment costs
- Lower residual aluminum content in the effluent → safer for potable water
3. Types of PAC Available on the Market
3.1. White PAC Powder (High-purity PAC Powder)
| Parameter | Value |
|---|---|
| Al₂O₃ Content | 29–31% |
| Basicity | 45–55% |
| Color | White |
| Packaging | 25 kg bags |
| Main Applications | Domestic water supply, drinking water, swimming pools |
Features: This is a high-purity PAC product, manufactured from high-quality Al(OH)₃ raw materials with very low levels of heavy metals and impurities. The white PAC powder meets drinking water standards (NSF/ANSI 60, GB 15892-2009).
Reference Price: 22,000 – 28,000 VND/kg
3.2. Yellow PAC Powder (Industrial-grade PAC Powder)
| Parameter | Value |
|---|---|
| Al₂O₃ Content | 27–29% |
| Basicity | 55–75% |
| Color | Light yellow to yellow-brown |
| Packaging | 25 kg bags |
| Main Applications | Industrial wastewater treatment, domestic wastewater treatment |
Features: An industrial-grade PAC produced from bauxite or industrial-grade Al(OH)₃, containing a small amount of iron impurities (which cause the yellow color). It offers high flocculation efficiency at a reasonable cost—making it the most popular choice for wastewater treatment plants.
Reference Price: 7,500 – 9,500 VND/kg
3.3. 10% Liquid PAC (Liquid PAC 10%)
| Parameter | Value |
|---|---|
| Al₂O₃ Content | 10–12% |
| Basicity | 60–80% |
| Color | Light yellow to light brown |
| Packaging | 200-liter drums, 1,000-liter IBCs, 5–20 m³ tanks |
| Main Applications | Large wastewater treatment plants, high-capacity water supply plants |
Features: Liquid form, ready to use—no mixing required. Suitable for plants with metering pump systems and large storage tanks. Lower cost when purchased in bulk (based on Al₂O₃). Limitations: higher shipping costs (transporting water), requires storage in corrosion-resistant tanks.
Reference Price: 1,800 – 2,500 VND/kg (equivalent to 18,000 – 25,000 VND/kg Al₂O₃)
3.4. Comparison Table of PAC Forms
| Criterion | White PAC Powder | Yellow PAC Powder | 10% Liquid PAC |
|---|---|---|---|
| Al₂O₃ | 29–31% | 27–29% | 10–12% |
| Purity | High | Medium | Medium |
| Price/kg of product | 22,000–28,000 | 7,500–9,500 | 1,800–2,500 |
| Price per kg of Al₂O₃ | ~80,000–90,000 | ~27,000–34,000 | ~18,000–25,000 |
| Intended Use | Drinking water, swimming pools | Wastewater | Large industrial plants |
| Preparation | Must be diluted | Must be diluted | Ready to use |
| Transportation | Cost-effective | Cost-effective | High cost |
| Storage | 12–24 months | 12–24 months | 3–6 months |
4. Applications of PAC
4.1. Wastewater Treatment — Primary Application
a) Industrial wastewater
PAC is the leading flocculant in wastewater treatment across the following industries:
- Textile and dyeing: Removes color, COD, and TSS. PAC works effectively with many types of dyes (reactive, disperse, direct, etc.). Color removal efficiency reaches 80–95%.
- Electroplating: Removal of heavy metals (Cr, Ni, Cu, Zn, etc.) via coprecipitation.
- Paper & Pulp: Removal of fibers, lignin, and reduction of COD
- Aquaculture: Removal of proteins, oils and fats, and TSS (see detailed Case Study in Lesson 6)
- Food & Beverage: Removes suspended solids, reduces BOD/COD
b) Municipal wastewater
In centralized wastewater treatment plants, PAC is used in the flocculation stage prior to the primary settling tank. Typical dosage: 30–80 mg/L, which helps:
- Reduce TSS by 70–90%
- Reduce BOD by 30–50%
- Reduce phosphorus by 60–90% (via AlPO₄ precipitation)
4.2. Potable Water Treatment — High Standards
In potable water treatment plants, white (high-purity) PAC powder is the preferred choice because:
- High flocculation efficiency with surface water (rivers, lakes) that has seasonally varying turbidity
- Low residual aluminum content, meeting QCVN 01-1:2018/BYT (< 0.2 mg/L Al)
- Stability at low temperatures — no loss of effectiveness in winter, unlike aluminum sulfate
- Typical dosage: 5–15 mg/L (low-turbidity water) to 25–40 mg/L (turbid floodwater)
4.3. Swimming Pool Water Treatment — Absolutely Crystal Clear
PAC is increasingly preferred for swimming pool water treatment over aluminum sulfate due to:
- Does not cloud the water even with slight overdosing (unlike aluminum sulfate)
- More stable pH → reduces the need to adjust pH with soda ash or HCl
- Lower dosage → less sediment settling at the bottom of the pool
Typical dosage: 2–5 g/m³ of pool water, diluted and evenly distributed over the surface.
4.4. Textile and Dyeing Industry — Dual-Purpose Application
In the textile and dyeing industry, PAC serves two purposes:
- Wastewater treatment: Decolorization, reduction of COD, and removal of TSS prior to discharge
- Dyeing process water treatment: Removal of hardness (Ca²⁺, Mg²⁺) — hard water affects dye quality
4.5. Other Applications
- Paper production: Retention aid, sizing
- Minerals: Flotation, dewatering of ore slurry
- Construction: Waterproofing additive for concrete
- Oil and gas: Production water treatment (produced water treatment)
5. Comparison of PAC vs. Aluminum Sulfate vs. FeCl₃
The three most common coagulants in water treatment are PAC, aluminum sulfate (Al₂(SO₄)₃), and FeCl₃. Below is a detailed comparison table to help you make the right choice:
5.1. General Comparison Table
| Criterion | PAC | Aluminum Sulfate Al₂(SO₄)₃·18H₂O | FeCl₃ |
|---|---|---|---|
| CAS | 1327-41-9 | 10043-01-3 | 7705-08-0 |
| Commercial Form | Powder/liquid | Granules/crystals | 40% liquid/solid |
| Active Ingredient Content | Al₂O₃ 10–30% | Al₂O₃ ~17% (hydrated form) | FeCl₃ 40% (liquid), ~60% (solid) |
| Optimal operating pH | 5.5–7.8 | 6.5–8.0 | 5.0–8.5 |
| Effect on pH | Slight decrease | Significant decrease | Significant decrease |
| Relative dosage | 1× (reference) | 2–3× | 1.5–2.5× |
| Sludge production | Low | High (highest) | Moderate |
| Water clarity after settling | Very good | Good | Good |
| Decolorization capacity | Very good | Average | Good |
| Effectiveness at low temperatures | Good | Poor | Good |
| Cost (relative) | Average | Lowest | High |
| Corrosiveness to equipment | Low | Low | High (corrosion-resistant equipment required) |
| Metal residues in water | Al³⁺ (low) | Al³⁺ (higher) | Fe³⁺ (may cause yellowing of water if present in excess) |
| Drinking Water Treatment | ✓ (white form) | ✓ (requires control of excess Al) | ✗ (generally not used for drinking water in Vietnam) |
5.2. Analysis of Each Substance
Aluminum Sulfate Al₂(SO₄)₃·18H₂O
- Advantages: The least expensive of the three types, readily available on the market, and familiar to operators
- Disadvantages: Dosage is 2–3 times higher than PAC, causes a significant drop in pH (requires addition of lime/soda ash), produces the largest amount of sludge, and is less effective when water temperature is < 15°C
- Suitable for: Small plants, limited budgets, water with high alkalinity
FeCl₃ (Iron (III) Chloride)
- Advantages: Widest operating pH range (5.0–8.5); forms heavy flocs that settle quickly; highly effective for water with organic color; performs well at low temperatures
- Disadvantages: Highly corrosive to equipment (requires 316 stainless steel or chemical-resistant plastic), causes yellow staining of tanks and pipes, high cost, risk of residual Fe causing yellowing of the effluent
- Suitable for: Industrial wastewater with high color, water with wide pH fluctuations
PAC
- Advantages: Low dosage, minimal impact on pH, large flocs — rapid settling, minimal sludge production, stable performance at all temperatures, low corrosion, suitable for both potable water and wastewater
- Disadvantages: Higher cost than aluminum sulfate (but lower total operating cost)
- Suitable for: Most water treatment applications, particularly potable water and multi-industry industrial wastewater
5.3. Total Cost of Ownership (TCO) Analysis
Many facilities focus solely on the price per kilogram of chemicals while overlooking “hidden” costs.” Below is a TCO analysis for a 1,000 m³/day wastewater treatment plant:
| Item | PAC | Aluminum sulfate | FeCl₃ |
|---|---|---|---|
| Chemical Costs | 6,000,000 | 4,500,000 | 5,800,000 |
| pH adjustment chemical costs | 0 (not required) | 1,500,000 | 2,000,000 |
| Sludge treatment cost | 12,000,000 | 20,000,000 | 15,000,000 |
| Maintenance costs (corrosion) | 500,000 | 800,000 | 3,000,000 |
| TOTAL/month | 18,500,000 | 26,800,000 | 25,800,000 |
→ PAC has the lowest total cost of ownership, even though its price per kilogram is higher than that of aluminum sulfate.
6. Purchasing Guide & Price Quotes
6.1. How to Choose the Right Type of PAC
| You need to treat… | You should choose… |
|---|---|
| Potable water, drinking water | White PAC powder (high-purity) |
| Swimming pool water | White PAC powder |
| General industrial wastewater | Yellow PAC powder |
| Textile and dyeing wastewater | Yellow PAC powder (high basicity) |
| Wastewater treatment plants with capacity > 5,000 m³/day | 10% liquid PAC |
| Wastewater treatment plants with capacity < 1,000 m³/day | Yellow PAC powder |
6.2. Considerations When Purchasing PAC
- Check the Al₂O₃ content: This is the key indicator of quality. You should request that the supplier provide a COA (Certificate of Analysis) for each batch
- Basicity: Higher basicity → less pH reduction, but this may come at the cost of slightly reduced solubility. For wastewater, a basicity of 55–75% is optimal
- Impurities: Important for potable water—check the levels of As, Pb, Cd, and Hg in the COA
- Intact packaging: Torn or damp PAC packaging will reduce quality because PAC strongly absorbs moisture
- Clear origin: Choose suppliers with VAT invoices, complete COAs, and transparent import or production sources
6.3. Reference Price Quote for Q3 2025
Note: Prices are subject to change based on market fluctuations and order quantity. Please contact us directly for the most accurate quote.
| Product | Specifications | Reference Price (VND/kg) |
|---|---|---|
| 30% White PAC Powder (China) | 25kg bag | 22,000 – 26,000 |
| White PAC Powder 31% (India) | 25kg bag | 25,000 – 30,000 |
| Yellow PAC Powder 28% (China) | 25kg bag | 7,500 – 8,500 |
| Yellow PAC Powder 30% (China) | 25kg Bag | 9,000 – 10,000 |
| Yellow PAC Powder 28% (Vietnam) | 25kg Bag | 8,000 – 9,500 |
| 10% Liquid PAC | 1,000L IBC / Tank | 1,800 – 2,500 |
Volume-Based Discount Policy:
- Orders of 1 metric ton or more: 3–5% discount
- Orders of 5 metric tons or more: 5–8% discount
- Orders of 10 metric tons or more: 8–12% discount
- Monthly/quarterly framework agreements: Fixed preferential pricing
6.4. Warehouse Network
Loc Thien Chemicals is proud to operate a network of 6 distribution warehouses across the country, ensuring fast delivery and cost-effective shipping for customers:
| Warehouse | Service Area | Delivery Time |
|---|---|---|
| Ho Chi Minh City | Ho Chi Minh City, Long An, Tien Giang, Binh Duong | 1–2 days |
| Ba Ria - Vung Tau | Ba Ria - Vung Tau, Dong Nai (southern part) | 1–2 days |
| Dong Nai | Dong Nai, Binh Duong, Binh Phuoc | 1–2 days |
| Da Nang | Da Nang, Quang Nam, Quang Ngai, Hue | 2–3 days |
| Can Tho | Can Tho, Hau Giang, Soc Trang, Kien Giang, Ca Mau | 2–3 days |
| Bac Ninh | Bac Ninh, Hanoi, Hai Duong, Hung Yen, Vinh Phuc | 2–3 days |
7. FAQ — 5 Frequently Asked Questions
Question 1: Is PAC safe for drinking water?
Answer: Yes — but only if you use white PAC powder (high-purity grade) that meets the NSF/ANSI 60 standard. This type of PAC has extremely low levels of heavy metals (As, Pb, Cd, Hg), ensuring it is safe for drinking water. Under no circumstances should you use yellow PAC powder (industrial grade) for drinking water, as it contains higher levels of impurities. Additionally, dosage must be carefully controlled to ensure the residual aluminum content in the treated water is ≤ 0.2 mg/L, in accordance with QCVN 01-1:2018/BYT.
Question 2: PAC and aluminum sulfate—which is better?
Answer: PAC is superior in most technical parameters: it requires a lower dosage, causes less pH reduction, produces less sludge, and maintains more stable performance at low temperatures. Aluminum sulfate has the advantage of a lower purchase price. However, when considering total cost of ownership (including pH adjustment chemicals, sludge treatment, and equipment maintenance), PAC typically has a lower cost (see the TCO table in Section 5.3).
Question 3: How should PAC be prepared?
Answer:
- PAC powder: Dissolve into a 5–10% solution (50–100 g PAC per 1 L of water). Gradually add the PAC powder to stirring water (do not do the opposite). Stir for 15–30 minutes until completely dissolved. The prepared solution should be used within 24–48 hours.
- 10% liquid PAC: Ready to use; simply stir gently before pumping if stored for an extended period. It can be further diluted if needed for small-volume applications.
- Safety Precautions: Wear gloves and safety goggles when mixing. Avoid inhaling PAC dust. If it comes into contact with skin, rinse immediately with clean water. PAC is mildly corrosive to metals—use PP/PE/FRP plastic tanks.
Question 4: Does PAC have an expiration date? How should it be stored?
Answer:
- PAC powder: Shelf life is 12–24 months from the date of manufacture. Store in a dry, cool, well-ventilated area (5–35°C), away from moisture (PAC strongly absorbs moisture—if exposed to moisture, it will clump and lose quality). Seal the bag tightly after opening.
- 10% liquid PAC: Shelf life of 3–6 months. Store in PP/PE/FRP plastic tanks (do not use metal tanks), away from high temperatures and direct sunlight. Gently stir before use if stored for more than 2 weeks.
Question 5: Where can I buy PAC from a reputable supplier at a good price?
Answer:
Loc Thien Chemicals is a reputable PAC supplier with 6 warehouses nationwide (Ho Chi Minh City, Ba Ria-Vung Tau, Dong Nai, Da Nang, Can Tho, Bac Ninh). We offer a full range of PAC forms:
- ✅ White PAC powder 30–31% (imported from China and India) — meets drinking water standards
- ✅ Yellow PAC powder 28–30% (imported + domestically produced) — optimized for wastewater treatment
- ✅ 10% liquid PAC — delivered in tanks directly to large plants
Our Commitment: Full COA, VAT invoices, fast delivery, and free technical support for jar tests for new customers.
Contact us now for a quote and consultation:
📞 Hotline: 0979 891 929
📧 Email: [email protected]
🌐 Website: hoachatlocthien.com
Lộc Thiên Chemicals — A trusted chemical partner for Vietnam’s water treatment industry.
Updated: August 2025. The information in this article is for reference only. For specific advice regarding your system, please contact Lộc Thiên Chemicals’ technical team directly.