When selecting geomembranes for chemical containment applications, engineers often debate between PVC (Polyvinyl Chloride) and LLDPE (Linear Low-Density Polyethylene). Both materials have distinct advantages, but their performance varies significantly in acidic, alkaline, and solvent-rich environments.
This article provides a data-driven comparison, including:
✔ Chemical degradation test results (pH 1-14)
✔ Cost vs. lifespan analysis (ROI breakdown)
✔ Expert recommendations for electroplating wastewater ponds
1. Chemical Resistance: Lab Test Results in Extreme pH Environments
Acid & Alkali Exposure Performance (ASTM D5322)
| Chemical | PVC Performance | LLDPE Performance |
| Sulfuric Acid (pH 1) | Good (5% swelling after 6 months) | Excellent (<1% swelling) |
| Sodium Hydroxide (pH 14) | Moderate (surface cracking at 12 months) | Excellent (no degradation) |
| Hydrochloric Acid (10%) | Poor (brittleness in 3 months) | Excellent (resistant) |
| Organic Solvents (Acetone) | FAILS (dissolves) | Good (limited absorption) |
Key Finding:
- LLDPE outperforms PVC in strong acids (HCl, H₂SO₄) and alkalis due to its non-polar structure.
- PVC degrades faster in oxidizing acids but handles weak acids (e.g., acetic acid) better than LLDPE.
2. Cost-Benefit Analysis: Initial Cost vs. Longevity
| Factor | PVC Geomembrane | LLDPE Geomembrane |
| Material Cost ($/m²) |  12 |  10 |
| Installation Cost | Higher (requires specialized welding) | Lower (easier heat fusion) |
| Lifespan (Years) | 10–15 (with UV protection) | 20–30 (superior chemical resistance) |
| Maintenance Cost | High (frequent seam repairs) | Low (stable in harsh conditions) |
ROI Example:
- A 10,000 m² electroplating pond using LLDPE saves $50,000+ over 20 years compared to PVC due to lower replacement frequency.
3. Expert Recommendation: Best Choice for Electroplating Wastewater Ponds
Why LLDPE Is Preferred for Metal Plating Facilities
✔ Resists cyanide & chromium baths (common in electroplating)
✔ No plasticizer leaching (unlike PVC, which degrades in heavy metals)
✔ Easier installation (no solvent welding required)
Case Study:
A Chinese electroplating plant switched from PVC to 1.5mm LLDPE, reducing liner replacements from every 8 years to 25+ years.
4. When Should You Use PVC Instead?
PVC remains viable for:
- Low-pH (<5) organic acids (e.g., food processing wastewater)
- Temporary containment (cost-driven projects under 5 years)
- Flexibility-critical applications (PVC is more pliable at low temps)
| Scenario | Recommended Material |
| Strong acids/alkalis | LLDPE |
| Organic solvents | LLDPE (PVC fails) |
| Budget-constrained, short-term use | PVC |
| Electroplating/chemical plants | LLDPE (best long-term value) |
Need a custom solution? Get a free chemical resistance assessment.
