Use of a composite material for absorbing carbon dioxide and volatile organic compounds in closed circuit or semi-closed circuit breathing apparatuses, composed of a mineral matrix (40%-95% weight concentration) and a carbonaceous component (5-60%).
| Patent title | Use of a composite adsorbent material for absorbing carbon dioxide and volatile organic compounds in closed circuit or semi-closed circuit breathing apparatuses |
|---|---|
| Thematic area | Health |
| Ownership | ALMA MATER STUDIORUM - UNIVERSITA' DI BOLOGNA |
| Inventors | Antonio Primante, Diego Marazza |
| Protection | Italy, with the possibility to extend internationally |
| Licensing status | Available for development, option, licensing and other enhancement agreements |
| Keywords | Absorption, adsorption, carbon dioxide, VOC, rebreather, biochar |
| Filed on | 03 May 2023 |
Rebreathers are devices for autonomous breathing in critical environments, mostly known for their use in scuba diving, but also common in miners and firefighters equipment. The rebreather system partially or totally recovers the exhaled gas, thus allowing to extend the autonomy of the operator.
The carbon dioxide produced by human metabolism is filtered by a system containing typically soda lime, a mixture of compounds having the ability to capture carbon dioxide passing through it.
However, the use of soda lime brings a number of inconveniences, among which a difficult monitoring of its residual absorbing capacity during usage (which can cause con conseguenti rischi di hypercapnia), potential harm in case of uncontrolled humidity content (the hydroxides in soda lime, when in contact with water, generate caustic, strongly alkaline solutions).
This invention concerns the use of a composite material in rebreather devices, as a saver alternative for soda lime. Such composite material is obtained by calcination of one or more carbonate compound (e.g. seashells, limestone, clay) and carbonaceous compounds (typically biomass coming from agricultural waste, such as vine pruning byproducts). The weight ratio of mineral over carbonaceous component in the composite material can vary between 40-60 and 95-5, but usualy a mineral content in the range 60-80% is preferred. The so-obtained composite material is in powder or granular form, with average particle size between 10 μm and 4 mm.
The composite can be employed in absorbing cartridges for rebreather devices, usually with particle size between 10 and 200 μm. It is in fact proven to be able to bind carbon dioxide and other VOCs (volatile organic compounds) effectively.
Applications:
- Filters in rebreather devices: scuba diving masks, breathers for hostile environment (e.g. mines, fires)
Main advantages:
- Stable material, it does not generate harming compounds when in come sin contact with uncontrolled humidity levels.
- Low-cost raw materials
- Exploitation of agricultural waste