Development of enclosed life support system for underground rescue employing a photocatalytic metal oxide thin film to generate oxygen from water and reduce carbon dioxide

Abstract

Despite major improvements in technology and safety regulations, coal mining continues to be a hazardous industry. Catastrophic accidents, related largely to underground explosions and generation of toxic gases, commonly result in the trapping of miners without oxygen for an extended period of time. As an example, in January 2006, an accident at the Sago Mine in West Virginia trapped 12 coal miners underground for 41 hours and resulted in the deaths of all but one. According to the account of the sole survivor, four of the emergency oxygen sources, or "air packs," failed. While devices capable of supplying oxygen to miners trapped underground exist, these systems are limited by the need for an exogenous gas supply, the large size of the devices, and unreliability. We propose here the design of an enclosed life support system functional for up to 12 hours, which employs photocatalytic mechanisms to generate oxygen from water and provides chemical reduction, or "fixation", of carbon dioxide. Oxygen is generated through a photolytic reaction involving the interaction of UV light and a titanium dioxide thin film, resulting in the generation of oxygen gas at a rate of 0.0507 L 02 / min per m2 of photolytic surface.

(cont.) Exhaled carbon dioxide is mechanically segregated from the oxygen and then fixed to a 5 carbon sugar molecule, ribulose, through a mechanism that includes the addition of carbon dioxide and water, the cleavage of the C2-C3 bond, and the ultimate generation of glyceric acid and its unlit. We contend that the system proposed here has the ability to significantly exceed the capacity of current emergency life support systems employed underground, and thereby improve the safety of coal miners and the overall productivity of the coal mining industry.