Experts in Humidity & Moisture Control

Equilibrium Adsorption of Mol Sieve Beads vs RH

How much water will Mol. Sieve Beads absorb

Molecular sieve is an alternative desiccant to Silica Gel. Whilst Silica Gel has a good level of adsorption throughout the RH spectrum, molecular sieve has exceptional capacity at very low relative humidity (RH). As such this is the desiccant of choice when your application requires a very low equilibrium RH for protection. This tool allows you to determine the specific adsorption capacity of molecular sieve with respect to RH. Shown graphically in Figure 1. This can then be used to determine the mass of silica gel required for a given application. We note that while there will be small variations with temperature, the adsorption values are very stable for all typical temperatures.

For example, if you have a moisture load of 100mg at 5% RH, then given the adsorption of 12g moisture per 100g desiccant, then you need 100mg/0.12 = 0.83g of molecular sieve.