A Comprehensive Guide to Desiccant Types and Their Best Uses
Effective moisture control is essential to prevent corrosion, mold, degradation, and condensation during storage and transport. Different desiccants operate on different principles and perform best under specific environmental conditions. Below is a structured overview of the main desiccant types used in industrial and packaging applications.
1. Calcium Chloride-Based Desiccants
What it is
Calcium chloride (CaCl₂) is a chemically active moisture absorber. Unlike purely adsorptive desiccants, it binds water through chemical absorption, converting moisture into liquid brine or gel as it hydrates. Once absorbed, the water is chemically locked and cannot be released under normal storage or transport conditions.
Key characteristics
- Extremely high absorption capacity, typically 300–350 % of its own weight in real transport conditions, and over 500 % in controlled high-humidity test environments
- Highly effective in high humidity (>60 % RH)
- Continuous moisture absorption over extended periods
- Long service life, typically at least three months from activation
- Moisture safely retained in integrated containment systems
Typical applications
- Shipping containers and export packaging
- Long ocean transit and intermodal transport
- Warehouses and storage areas prone to condensation
- Closable rooms and humidity-exposed utility spaces
Commonly protects metals, agricultural products, food and beverages, textiles, footwear, timber, furniture, machinery, and consumer goods.
When to choose it
Best suited for maximum moisture removal over prolonged periods, particularly in large enclosed volumes such as containers, and where high humidity or container rain is expected. Ideal when traditional adsorptive desiccants would saturate too quickly.
2. Activated Clay (Bentonite) Desiccants
What it is
Activated clay is a natural desiccant derived from bentonite (typically calcium bentonite). It removes moisture through physical adsorption onto its surface.
Standards
Commonly manufactured in compliance with DIN 55473 and MIL-D-3464E for industrial desiccant bags.
Key characteristics
- Natural, non-toxic, and environmentally friendly
- Stable performance across a broad humidity range
- Often performs well in low humidity (<30 % RH)
- Suitable for industrial-grade dust-proof packaging
- Moisture absorption capacity ~20 % of own weight.
Typical applications
- Export and industrial packaging
- Protection of metal parts, textiles, leather, and machinery
- Large-format desiccant bags for containers and palletized goods
- Food and pharmaceutical packaging requiring non-toxic materials
When to choose it
A reliable, cost-effective solution for general moisture protection under moderate humidity conditions, especially in industrial and large packaging formats.
3. Silica Gel Desiccants
What it is
Silica gel is a porous, amorphous form of silicon dioxide with a very high internal surface area. It removes moisture through physical adsorption within its pore structure.
Standards
Widely produced in compliance with DIN 55473 and MIL-D-3464E for industrial and military packaging applications.
Key characteristics
- Efficient adsorptive moisture removal
- Moisture absorption capacity ~30 % of own weight.
- Can be regenerated by heating (approx. 120 °C)
- Chemically inert and non-toxic
- Stable and predictable performance
Typical applications
- Consumer packaging
- Electronics and semiconductors
- Pharmaceutical products
- Small enclosed spaces (instrument cases, cabinets, toolboxes)
When to choose it
Ideal for medium humidity environments, smaller sealed volumes, and applications where regeneration, chemical inertness, and packaging safety are important.
4. Activated Alumina Desiccants
What it is
Activated alumina is a highly porous form of aluminum oxide (Al₂O₃), produced through thermal activation to create strong adsorption capacity.
Key characteristics
- High surface area and strong moisture adsorption
- Regenerable through heating
- Mechanically robust
- Suitable for demanding industrial conditions
- Moisture absorption capacity ~20 % of own weight.
Typical applications
- Compressed air and gas drying systems
- Petrochemical and chemical processing
- Industrial moisture removal in process streams
- Certain specialized packaging applications
When to choose it
Best suited for industrial air and gas drying systems and applications requiring a durable, regenerable desiccant with stable performance in continuous processes.
5. Molecular Sieve Desiccants
What it is
Molecular sieves are synthetic crystalline aluminosilicates (zeolites) with precisely defined pore sizes, enabling selective and highly efficient adsorption of water molecules.
Standards
Frequently manufactured in accordance with DIN 55473 and MIL-D-3464E when supplied in bagged desiccant formats.
Key characteristics
- Extremely effective at very low humidity levels (<10 % RH)
- Performs well even at low temperatures
- Can selectively adsorb specific molecules
- Higher cost but superior performance in critical environments
- Moisture absorption capacity ~25 % of own weight.
Typical applications
- Pharmaceuticals and diagnostics
- Precision electronics
- Technical packaging requiring ultra-dry conditions
- Specialized industrial gas and liquid drying
When to choose it
Recommended when very low final humidity levels are required, or when environmental conditions exceed the capabilities of silica gel or activated clay.