## 3 Results  
### Microscopic Evaluation of Morphological Properties  
The morphological properties of the studied zeolite and silicon materials as well as the nonwoven composites are shown in Figures 2-6. Figure 2a shows zeolite Na-A produced by the hydrothermal method from the dissolved crystalline phase of fly ash. Zeolite Na-A particle represents the Linde A-like framework (code LTA according to IZA atlas structure) in which 6-membered rings form regular 4.1 \(\times\) 4.1 A channels. Its 2-5 \(\upmu\)m crystals have a regular structure. In the case of the Na-A composite (Figure 2b), individual zeolite particles were attached to elementary polymer fibers with a uniform distribution across the nonwoven. Zeolite Na-A impregnated with HDTMA is shown in Figure 2c; its crystals are covered with a thin layer of HDTMA. Zeolite Na-A HDTMA particles incorporated in the nonwoven composite (Figure 2d) had a tendency to agglomerate. In addition to individual particles attached to the fibers, large quantities of agglomerated Na-A HDTMA powder were found mostly in spaces between the  
entangled polymeric fibers. Zeolite modification led to agglomeration already at the stage of zeolite introduction in the melt-blown process. Approximately 55 g of zeolites Na-A and Na-A HDTMA were incorporated per nonwoven sheet. Figure 3a presents the morphology of Zeolite Na-P1 formed on ash grains as a result of a hydrothermal reaction between an aqueous solution of sodium hydroxide and ash components, such as: Aluminosilicate glass, quartz, and mullite. Zeolite Na-P1 represents a gismondine-like framework (code GIS according to the IZA atlas structure) in which two 4-membered rings form an 8-membered channel measuring 3.1 \(\times\) 4.5 A and 2.8 \(\times\) 4.8 A along their axes, respectively. Zeolite Na-P1 plates-like crystals with sharp edges form characteristic 1-3 \(\upmu\)m rosettes. In turn, the modified zeolite Na-P1 HDTMA exhibits rounded crystal edges (Figure 3c). Approximately 123 g of zeolites Na-P1 and Na-P1 HDTMA were incorporated per nonwoven sheet. Both zeolite types had a tendency to agglomerate, as shown in Figure 3b,d. The spaces between fibers are filled with a large number of agglomerates, which are much larger than the polymeric fiber diameters. Figure 4a presents cylindrical forms of MCM-41 with a hexagonal structure. That material consists of 99% silicon, while the impregnated variant additionally contains HDTMA (Figure 4c). The incorporation of MCM-41, which has a low specific weight, in the polymeric nonwoven structure resulted in its uniform distribution (Figure 4b). Both individual particles and small agglomerates of  
Figure 2: SEM photomicrograph: (**a**) Unmodified zeolite Na-A, (**b**) nonwoven composite with Na-A, (c)zeolite Na-A HDTMA, (**d**)nonwoven composite with Na-A HDTMA (magnification: a,c—x30.00k; b,d—x2.00k). this silica material were attached to the surface of polymeric fibers. The HDTMA modification of MCM-41 led to a tendency to form large agglomerates locked in the nonwoven scaffold (Figure 4d). The SM 4A molecular sieve particles shown in Figure 5a have a more complex form as compared to SM particles (Figure 6a). The SM molecular sieve is zeolite ZSM-5, which consists of a system of pores formed by straight, parallel 10-membered channels measuring 5.3 \(\times\) 5.6 A as well as sinusoidal 10-ring channels (5.5 \(\times\) 5.1 A). The SM molecular sieve, which was introduced into the polymeric nonwoven in small quantities (approximately 18 g per sheet), is uniformly distributed (Figure 6b). Individual particles were attached to elementary fibers, with some fine agglomerates in interfiber spaces. Interestingly, more agglomerates were found attached to the surface of polymeric fibers. In turn, the SM 4A molecular sieve had a strong tendency to form agglomerates (much larger than elementary fiber diameters) in interfiber spaces (Figure 5b).