Carbon monoxide elimination for health and safety: new powerful silica-based adsorbents applied in continuous breakthrough experiments at elevated laboratory scale

Abstract

The adsorption of carbon monoxide (CO) is difficult and the degree of elimination requested is very high, due to the high toxicological risk of CO. Nevertheless, only a few studies deal with this topic. The presented investigations are based on powerful functionalized silica adsorbents which deliver very fast separation kinetics in combination with high binding capacities. Even at very low CO concentrations of 0.9 and 85 ppmv, respectively, high adsorption rates for all investigated adsorbents were detected. In order to demonstrate the effectiveness and selectivity of the new adsorbents, breakthrough experiments at elevated laboratory scale (gas flow rate of 300 mL min−1) were executed with a high CO feed gas concentration of 10,000 ppmv. The experimental results prove that 20 g of the new functionalized silica adsorbent HSU 001-075.2 made sure that the “Eight Hours EC Occupational Exposure Limit Value” of 100 ppmv CO in the air was not exceeded for at least 200 s. In that context, a realistic fire scenario with respect to the CO burden of first responders was focused. The protective efficiency of the new adsorbents was exemplary calculated for the new functionalized adsorbent HSU 031-295.1. According to that, an amount of approximately 0.35 kg is able to decrease a CO concentration of 1000 ppmv in the breathing air of one person under high physical strain (assumed air demand 95 L min−1) to a maximum concentration of 83 ppmv for a protection time of 10 min. In case of a collective fire protection shelter occupied by 10 persons under low physical strain (air demand 30 L min−1), an amount of 3.1 kg is sufficient for their protection against CO intoxication over an assumed time interval of 60 min. These results verify the suitability of the upscaled arrangement of the new developed process for worker’s safety installations as well as for protective equipment of emergency services.