PASP (Polyaspartic Acid) is a biodegradable, non-toxic, and highly effective green alternative to traditional scale and corrosion inhibitors like phosphonates (HEDP, ATMP) and synthetic polymers (PAA, HPMA). Below are its key advantages:
1. Environmental & Safety Benefits
✅ Fully Biodegradable (>60% in 28 days per OECD 301B) – Unlike persistent phosphonates (HEDP/ATMP).
✅ Non-Toxic (EC50 >100 mg/L for aquatic organisms) – Safe for marine and freshwater ecosystems.
✅ No Phosphorus or Nitrogen – Prevents eutrophication in lakes/rivers.
✅ REACH & EPA Approved – Compliant with strict environmental regulations (e.g., EU Water Framework Directive).
2. Superior Technical Performance
(1) Scale Inhibition
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Effective against:
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CaCO₃ (80–90% inhibition at 10–20 mg/L).
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CaSO₄, BaSO₄, and Ca₃(PO₄)₂ (better than PESA in high-salt water).
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Threshold Effect: Works at substoichiometric doses (1–5 mg/L in mild scaling conditions).
(2) Corrosion Inhibition
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Forms a protective film on carbon steel, copper, and aluminum (corrosion rate <1 mpy with 15 mg/L PASP).
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Synergistic with zinc ions and molybdate for enhanced protection.
(3) Dispersion & Fouling Control
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Prevents deposition of:
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Iron oxide (Fe₂O₃) – Critical in cooling towers and boilers.
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Clay/silt – Used in desalination and oilfield water.
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3. Operational & Economic Benefits
💰 Reduces Sludge Formation – Lowers cleaning and waste disposal costs.
🔥 Thermal Stability – Performs up to 100°C (better than PESA).
💧 Broad pH Range (5–12) – Effective in alkaline and acidic systems.
🔄 Compatible with Oxidizing Biocides (e.g., chlorine, bromine) – Unlike HEDP/ATMP.
4. Comparison with Other Green Inhibitors
| Feature | PASP | PESA | HEDP |
|---|---|---|---|
| Biodegradability | >60% (OECD 301B) | >60% (OECD 301B) | <30% |
| Phosphorus-Free | ✔️ Yes | ✔️ Yes | ❌ No (High P) |
| Scale Inhibition | ★★★★★ (Best for CaCO₃/BaSO₄) | ★★★★☆ (Good for CaCO₃) | ★★★★★ (But non-eco) |
| Cost | $$ (Moderate) | $ (Low) | $ (Low) |
5. Ideal Applications
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Cooling Water Systems (Zero-P discharge requirements)
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Seawater Desalination (RO/MED) – Resists CaSO₄/BaSO₄ scaling.
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Oilfield Water Injection – Prevents CaCO₃ and iron fouling.
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Pulp/Paper & Textile Industries – Meets eco-certification standards.
Why Choose PASP Over PESA?
While PESA is cheaper, PASP offers:
✔ Better high-temperature stability (up to 100°C vs. 80°C for PESA).
✔ Stronger inhibition of BaSO₄/SrSO₄ (critical in oil/gas applications).
✔ More effective in high-hardness water (e.g., >500 mg/L Ca²⁺).
Conclusion
PASP is the top eco-friendly choice for industries needing high-performance, sustainable water treatment. It outperforms PESA in harsh conditions while remaining biodegradable and non-toxic. For cost-sensitive applications, PESA may suffice, but for demanding environments (oilfields, high-temperature systems), PASP is superior.