Improving the adsorption performance and surface roughening of rayon fibers via enzymatic treatment with cellulase

In recent years, expectations have increased for the development of filters for removing air pollutants. Rayon fibers have rough surfaces and excellent adsorption characteristics. Therefore, rayon is a promising material for such filters. By further roughening its surface, its adsorptivity to substances such as volatile organic compounds can likely be improved. The surface of rayon fibers was roughened via wet spinning carried out by adding oleic acid to a raw viscose. As a result, porous fibers containing several pores with a diameter of about 0.5–1.0 µm were obtained. A weight reduction treatment of the porous rayon fibers with cellulase, a cellulose-degrading enzyme, resulted in the appearance of several streaks and asperities on their surfaces. To investigate the adsorption behavior of the rayon fibers after cellulase treatment, dye adsorption was examined using an aqueous methylene blue solution. The porous rayon fibers adsorbed much more dye than the regular fibers. In addition, the fibers absorbed more dye after treatment with cellulase than without treatment in both fibers. The deodorizing function of the rayon fibers was also investigated using ammonia gas. The porous rayon fibers treated with cellulase had a very high deodorizing effect. In the proposed study, rayon fibers (which are porous inside) were treated with cellulase, and their surface was found to be considerably rough.