Nanostructured surface
Natural zeolites modified with silver nanoparticles as promising sorbents with antibacterial properties 
Patrylak L.K.1,2, Yakovenko A.V.1, Nizhnik B.O.1,2, Pertko O.P.1, Povazhnyi V.A.1
1 Department of Catalytic Synthesis, V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of NAS of Ukraine. Murmanska Str., 1, Kyiv-02094, Ukraine E-mail: lkpg@ukr.net
2 Depatment of Technology of Inorganic Substances, Water Treatment and General Chemical Technology, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”. Peremohy ave., 37, Kyiv-03056, Ukraine    

Today, more than eighty types of natural zeolites are known [1, 2]. The latter, in contrast to synthetic zeolites, usually contain a number of impurities from other rocks. Clinoptilolite, as a zeolite of the gaylandite group, finds considerable application [3] in various fields. It is one of the most stable and common natural zeolites in the world, deposits of which are available in Transcarpathia. The shortcomings of the porous structure of the clinoptilolite, on the other hand, limit the widespread usage of Ukrainian natural zeolites. 
The aim of this study was to use a complex modification of natural zeolites to obtain promising silver-containing antibacterial sorbents with improved porosity.
 The original rock was clinoptilolite-type zeolite from the Sokyrnytsia deposit (Transcarpathian region). The first stage of its modification was the expansion of the pores by four times dealumination/decationation by ethylenediamine tetraacetic acid. This gentle treatment increased the SiO2/Al2O3 ratio from 7.3 to 8.7, increased the specific surface area to 90 m2/g, and the micropore volume to 0.036 cm3/g. Additionally, the sample was doped with silver in the amount of 1 wt% using silver nitrate. The obtained zeolite sample is a promising sorbent with antibacterial properties.

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