Influence of complex fibrous media composition on their performances for VOC and particle removal

Amongst atmospheric pollutants, two major types can be distinguished: airborne particles such as dust, and gaseous compounds such as Volatile Organic Compounds (VOCs). Fibrous filters are commonly used to remove particles while activated carbon beds trap VOCs. In order to obtain a single-stage device as efficient at collecting particles with a size less than 10 microm (PM10) as removing VOCs, prototype fibrous media containing activated carbon fibers (ACF) associated with cellulose fibers (CF), which are non-adsorptive, have been developed. The influence of ACF ratio and the degree of beating of CF on porous structure, mechanical strength and treatment performances of the medium was studied. Experimental results show that an increase in ACF mass ratio increases the inter-fiber porosity and overall adsorption capacity (the intrinsic adsorption capacity of ACF remains constant whatever the composition), but decreases the mechanical strength and particle collection efficiency of the medium. Moreover, an increase in the beating of CF enhances the mechanical strength of the medium and its particle collection efficiency, but decreases its porosity and has no effect on adsorption capacity. Consequently, a medium containing 50% ACF associated with CF with a low degree of beating (16 degrees SR) presents the best performance for combined filtration.