Molecular Sieve vs Silica Gel – which is better? …This is a question that we get asked frequently, here at Baltimore Innovations, and the answer is: …it depends on your application.
In terms of their use within desiccant packets, both Molecular Sieve and Silica Gel have their advantages. Silica Gel packets will typically adsorb 35% of their own weight, compared to Molecular Sieve sachets, which will pull-in a figure closer to 22%. As a result, you may think that Silica Gel is better, and you would be right, if your aim is to remove as much humidity as is possible with the same 1g, 5g, or 25g bag of desiccant. However, you should also note that Molecular Sieve has a much higher affinity for water absorption. This means that (when dosed correctly), the same 5g sachet of Molecular Sieve will take the Relative Humidity, of an air-tight package, right down to 0%. This compares very favourably to Silica Gel which (even when dosed correctly), only has the absorptive strength take the RH down to 5%. As a result of this performance difference, manufacturers of Pharmacutical pills, who require zero moisture, will favour Molecular Sieve Sachets above silica Gel sachets.
That said, it worth noting that Silica Gel Sachets are generally less expensive that those containing molecular sieve, so in the cases where ‘absolute zero’ humidity is not required, silica gel is the normally the desiccant of choice.
Another advantage of silica gel is that it will likely not damage products by over-desiccating them. This performance characteristic is best seen in our pre-damped silica gel sachet range called
HUMI-BALANCE™. These humidity-regulator sachets, are ideal for the preservation of organic products, which cannot get too try, else they will become too brittle, nor too wet, as they will develop mold. Noteworthy uses of this technology include the preservation of dried meats such as Biltong, and also the maintenance of a packed environment for tobacco products. With both of these applications, you need a packed environment that is ‘not too dry’ and also ‘not too damp’, and HUMI-BALANCE™ provides this min-point environment, perfectly!
To learn more about SUPERDRYPAK™ Silica Gel packets, or SUPERDRYPAK™ Molecular Sieve Sachets, or even our new range of HUMI-BALANCE™ Sachets, then please speak to my colleague Philippe Depois. He has over 30 years’ experience advising customers on these products – and is therefore one of the world’s foremost authorities on the subject. You can contact him by clicking here.
If you want to know more about the relative merits of Silica Gel vs Molecular Sieve in Industrial Air Drying applications; where these two desiccants are not supplied as packets, but instead as large drums (or sacks) of bulk fill media, then please speak to my colleague Ricardo Cremonini. With a name like that, you might imagine him to be an Italian racing-car driver, but he is in-fact one of the UK’s leading experts on industrial bulk desiccants. To contact Ricardo, please just click here
Lastly, if you want to know more about the relative merits of Silica Gel vs Molecular Sieve Powders* (*also known as Zeolite Powders) for use within polymer applications, then please speak to me, because on this topic, it’s me that’s the expert! To book a call-back, please just click here