What is PAC? Poly Aluminium Chloride — Properties, Applications & Where to Buy
5 Key Points to Remember:
- PAC (CAS 1327-41-9) is an aluminum polymer coagulant, 2–3 times more effective than traditional aluminum sulfate
- Works effectively across a wide pH range (5.0–9.0), causes less pH reduction than alum
- 4 main commercial forms: PAC 31% (liquid), PAC 10% (liquid), PAC 17% (liquid), PAC powder 28–30%
- Applications in potable water treatment, industrial wastewater, swimming pools, textile dyeing, paper production
- Loc Thien delivers within 24h to industrial zones nationwide — call 0979 891 929 for quotes within 15 minutes
1. What is PAC?
PAC — short for Poly Aluminium Chloride — is an inorganic aluminum polymer compound with the general formula [Al₂(OH)ₙCl₆₋ₙ·xH₂O]ₘ where m ≤ 10 and n ≤ 5. As a second-generation coagulant developed from traditional aluminum sulfate, PAC demonstrates significantly higher coagulation efficiency due to its pre-hydrolyzed polymer structure.
PAC is produced through the reaction between aluminum hydroxide Al(OH)₃ and hydrochloric acid HCl under controlled temperature and pressure, resulting in a product with basicity ranging from 40–85%. This basicity determines the hydroxyl group content in the polymer chains, directly affecting coagulation performance and optimal pH range.
Compared to conventional alum Al₂(SO₄)₃·18H₂O, PAC offers four superior advantages:
| Criteria | PAC | Aluminum Sulfate |
|---|---|---|
| Mechanism | Pre-hydrolyzed polymer — fast coagulation | Hydrolyzes in water — slower reaction |
| Optimal pH Range | 5.0–9.0 (wide) | 6.5–7.5 (narrow) |
| Sludge Volume | 30–50% less | Higher, contains more sulfate |
| Post-Treatment pH Impact | Slight reduction (≤0.5 units) | Significant reduction (1.0–2.0 units), requires alkali addition |
| Low-Temperature Performance | Good (stable at 5–35°C) | Poor below 15°C |
2. PAC Technical Specifications — TDS Sheet
The table below summarizes technical parameters for the four most common PAC forms in Vietnam’s market, based on GB 15892-2020 (China) and equivalent TCVN standards — actual COA varies by production batch.
| Parameter | PAC 31% (Liquid) | PAC 17% (Liquid) | PAC 10% (Liquid) | PAC Powder 28–30% |
|---|---|---|---|---|
| Al₂O₃ Content | ≥ 10.0% | ≥ 5.0–5.5% | ≥ 3.0–3.5% | ≥ 28.0% |
| Basicity | 45–85% | 40–85% | 40–85% | 40–90% |
| Density (20°C) | 1.19–1.21 g/cm³ | 1.08–1.12 g/cm³ | 1.04–1.06 g/cm³ | — (powder) |
| pH (1% solution) | 3.5–5.0 | 3.5–5.0 | 3.5–5.0 | 3.5–5.0 |
| Color | Light yellow to reddish brown | Light yellow to light brown | Light yellow, clear | Off-white to light yellow |
| Form | Viscous liquid | Liquid | Liquid | Fine powder |
| Standard Packaging | 5–24 ton tanks; 1,000L IBC; 200L drums | 200L drums; 1,000L IBC | 200L drums; 30L cans | 25kg PP/PE bags |
| Impurities (Fe, As, Pb, Hg, Cd, Cr⁶⁺) | Batch-specific COA — meets TCVN | Batch-specific COA | Batch-specific COA | Batch-specific COA |
Note: Values are typical. Request actual batch COA/MSDS from Loc Thien.
3. PAC Types — Which One to Choose?
3.1. PAC 31% (Concentrated Liquid)
PAC 31% has the highest Al₂O₃ content (~10%) among liquid forms, appearing yellow to reddish-brown. The preferred choice for large-scale urban water plants and wastewater facilities (>5,000 m³/day). Higher concentration reduces transportation cost per active kg. Loc Thien delivers PAC 31% via 5–24 ton tankers directly to plant storage.
3.2. PAC 10% (Diluted Liquid)
PAC 10% (~3.0–3.5% Al₂O₃) suits small to medium systems, swimming pools, or operations without large storage. Advantages: easy dosing, low viscosity ensures stable metering pump operation. Ideal for customers transitioning from alum to PAC.
3.3. PAC 17% (Mid-Range Liquid)
PAC 17% (~5.0–5.5% Al₂O₃) balances performance and logistics cost. Popular in textile dyeing and paper mills for excellent color removal at competitive pricing.
3.4. PAC Powder 28–30%
The most concentrated form (≥28% Al₂O₃), packed in 25kg bags — optimal for long-distance transport and export. Customers dilute to 5–10% solution before dosing. Lowest transportation cost per active kg. Loc Thien supplies PAC powder to Central Vietnam, Highlands, and exports to Laos/Cambodia.
4. PAC Coagulation Mechanism
When PAC dissolves in water, three mechanisms occur simultaneously:
Mechanism 1 — Charge Neutralization: Colloidal particles (clay, organics, bacteria) carry negative surface charges that prevent settling. Al³⁺ ions from PAC neutralize these charges, reducing repulsion energy.
Mechanism 2 — Polymer Bridging: Unlike alum (only charge neutralization), PAC’s polymer chains [Al₂(OH)ₙCl₆₋ₙ]ₘ act as “bridges” — one end attaches to one particle, another end to adjacent particles — forming larger flocs.
Mechanism 3 — Sweep Coagulation: At higher doses, Al(OH)₃ precipitates as “snowflake” flocs that enmesh suspended particles during settling.
This triple-action makes PAC flocs larger, faster-settling, and more effective against both turbidity and organic color than conventional alum.
5. Key PAC Applications
5.1. Potable Water Treatment
PAC is Vietnam’s #1 coagulant for drinking water plants. Typical dosage: 15–40 mg/L depending on raw water turbidity. Effectively removes turbidity, dissolved organic carbon (DOC), bacteria, and heavy metals — compliant with QCVN 01-1:2018/BYT standards. Notably, PAC leaves lower aluminum residuals (<0.2 mg/L per TCVN) than alum.
5.2. Industrial Wastewater Treatment
Industrial zones (textile, electroplating, paper, food processing) use PAC for COD, color, and TSS removal before discharge. Dosage: 50–300 mg/L based on pollutant load. Particularly effective for textile wastewater — removes up to 90% reactive dyes when combined with anionic polymer.
5.3. Swimming Pool Treatment
PAC serves as a filter aid in pool recirculation systems, removing sub-5 micron particles that sand filters miss. Dosage: 5–10 mg/L, applied weekly.
5.4. Textile Dyeing (Color Fixation)
In fabric dyeing, PAC acts as a color-fixing agent — ensuring even, durable dye absorption. For textile wastewater, PAC + cationic polymer achieves 95% color removal.
5.5. Paper & Pulp Production
PAC improves retention of cellulose fibers and fillers on paper machine wires, reducing material loss and enhancing paper whiteness.
6. Usage & Safety Guidelines
6.1. PAC Solution Preparation
- For PAC powder: dissolve in clean water to make 5–10% solution (ADD POWDER TO WATER while stirring — never reverse)
- Stir 30–60 minutes until fully dissolved
- Settle 2–4 hours, decant clear supernatant — discard bottom sediment
- Dose into treatment system via metering pump
6.2. Compatible Materials
| Material | Recommendation |
|---|---|
| Storage Tanks | FRP, HDPE, PP, PVC, rubber-lined |
| AVOID | Carbon steel (unlined), stainless steel (eventually corrodes — even SS304/316 with prolonged exposure), aluminum, copper |
| Metering Pumps | PTFE/EPDM diaphragm pumps; PVC/PP pump heads |
6.3. Personal Protective Equipment (PPE)
- Chemical-resistant gloves (nitrile/neoprene)
- Safety goggles
- Dust mask (when handling PAC powder)
- Long-sleeve protective clothing
6.4. First Aid
- Eye Contact: Flush under running water for 15 minutes, seek medical help
- Skin Contact: Remove contaminated clothing, wash with soap/water
- Inhalation: Move to fresh air, keep warm
- Ingestion: Rinse mouth, DO NOT induce vomiting, seek immediate medical attention
6.5. Storage
- Temperature: 5–35°C, avoid direct sunlight
- Shelf life: 6–12 months from production (varies by form, see COA)
- Liquid PAC: prevent freezing (<0°C causes irreversible precipitation)
- Powder PAC: store in dry place, seal bags after opening — highly hygroscopic
7. Loc Thien — PAC Supplier for Factories & Industrial Zones
Loc Thien Chemicals is Vietnam’s leading water treatment chemical supplier:
- 6 nationwide warehouses: Stock always available in Binh Duong, Ho Chi Minh City, Dong Nai, Long An, Hanoi, Da Nang — same-day delivery to key industrial zones.
- 20 specialized tanker trucks: Transport 5–24 tons/liquid PAC shipment safely with no cross-contamination.
- Batch-specific COA/MSDS: Full transparency with Certificate of Analysis and Material Safety Data Sheet for every batch.
- Free technical consultation: Loc Thien engineers assist with site surveys, optimal dosage calculations, and on-site jar testing.
Call 0979 891 929 — quotes within 15 minutes.
8. Frequently Asked Questions
Can PAC completely replace aluminum sulfate?
Yes. PAC can replace alum in most water treatment applications with higher efficiency. However, jar testing is required to determine optimal dosage for specific water sources — no fixed conversion ratio applies.
PAC 31%, 10%, 17% — which to choose?
Depends on capacity and logistics. >5,000 m³/day → PAC 31% (transport savings). Small systems, no large storage → PAC 10%. Textile/paper → PAC 17% (cost-performance balance). Export/long-distance → PAC powder 28–30%.
How to prepare PAC powder? What water to use?
Dissolve PAC powder in clean water (tap or non-ferruginous well water) to make 5–10% solution. ADD POWDER TO WATER while stirring — never reverse. Stir 30–60 mins, settle 2–4 hrs, use clear supernatant.
Is PAC corrosive to equipment?
Yes. PAC’s pH 3.5–5.0 and chloride ions corrode metals. Use FRP/HDPE/PVC tanks — never carbon steel or stainless steel for prolonged contact.
Where to buy reliable, affordable PAC?
Loc Thien Chemicals — 6 nationwide warehouses, 20 specialized tankers, batch-specific COA/MSDS. Call 0979 891 929 for quotes within 15 mins. 24h delivery to Binh Duong, Dong Nai, HCMC, Long An, Hanoi, Da Nang industrial zones.
Can PAC treat arsenic-contaminated water?
Yes. PAC precipitates As(V) with >90% efficiency at pH 6.5–7.5. For As(III), oxidize to As(V) first using NaOCl or KMnO₄ before PAC treatment.
LOC THIEN INVESTMENT DEVELOPMENT CO., LTD
Tax Code: 0313650856 — Address: 219/19A, Binh Phuoc B Hamlet, Binh Chuan Ward, Thuan An City, Binh Duong
Hotline: 0979 891 929 — Email: [email protected]
Website: hoachatlocthien.com