Nanocomposites and nanomaterials

Influence of cavitation and non-cavitation ultrasonic treatment on the structure of nanoporous carbon materials
Ptashnyk V.1, Bordun I.2,3, Maksymych V.3, Malovanyy M.3, Calus D.2, Chabecki P.2, Szymczykiewicz E.2
1 Lviv National University of Nature Management, 1, Vol. Velykogo str., Dubliany, Lviv region, 80381, Ukraine.
E-mail: ptashnykproject@gmail.com
2 Czestochowa University of Technology, 69, Dabrowskiego str., Czestochowa, 42-201, Poland.
3 Lviv Polytechnik National University, 12, Bandera str., Lviv, 79013, Ukraine.

Activated carbon (AC) are the most common adsorbents and materials for the manufacture of electrodes of charge storage systems. This is due to the well-developed porous structure, good electrical conductivity, environmental friendliness and cheapness. However, traditional methods of obtaining AC do not give the desired quality material. Therefore, such carbon needs to be further modified, for example, using ultrasonic (US) technology.
For experimental studies the AC obtained by pyrolysis of birch wood was used. The process temperature was 800 ºC, activation time 90 min. AC was placed in the reactor of the ultrasonic unit BAKU-9050 to study the effect of US in cavitation mode. Non-cavitation treatment of the AC was performed in a spherical US reactor. The processing time was selected so that the energy of both types of exposure was the same. The parameters of the porous structure of AC were determined by isothermal adsorption/desorption of nitrogen an automated analyzer Quantachrome NOVAtouch LX2. X-ray diffraction curves of carbon materials and small-angle X-ray scattering (SAXS) spectra were obtained using a DRON-3 diffractometer.
The diffraction patterns of the samples show wide diffuse maxima localized in the vicinity of the diffraction angles 2θ°≈ 23.90° and 2θ°≈ 43.50°, which are characteristic of the structure of amorphous carbon. Analysis of SAXS spectra and nitrogen adsorption/desorption isotherms showed that cavitation US treatment a decrease the specific surface area from 595 m2/g to 530 m2/g. More significant changes in the porous structure are observed after non-cavitation treatment. As a result, we have an increase in the specific surface area to 719 m2/g. Thus, US in both cavitation and non-cavitation modes helps to change the porous structure of the nanostructured AC and can be used for controlled modification of the AC.