In the paper, differential quadrature method (DQM) is used to find numerical solutions of reaction-diffusion equations with different boundary conditions. The DQM-method changes the reaction- diffusion equation (ordinary differential equation) into a system of algebraic equations. The obtained system is solved using built-in procedures of Maple®(Computer Algebra System-type program). Calculations were performed with Maple®program. The test problems include reaction-diffusion equation applied in heterogeneous catalysis. The method can be employed even in relatively hard tasks (e.g. ill-conditioned, free boundary problems).

There is general agreement that primary pyrolysis products of end-of-life tyres should be valorised to improve the economics of pyrolysis. In this work, tyre pyrolysis char (TPC) is produced in a pyrolysis pilot plant designed and built at our home university. The produced TPC was upgraded to tyre-derived activated carbon (TDAC) by activation with CO2, and then characterised using stereological analysis (SA) and nitrogen adsorption at 77 K. SA showed that the grains of TPC and TDAC were quasi- spherical and slightly elongated with a 25% increase in the mean particle cross-section surface area for TDAC. The textural properties of TDAC demonstrated the BET and micropore surface areas of 259 and 70 m2/g, respectively. Micropore volume and micropore surface area were 5.8 and 6.7 times higher for TDAC than TPC at  2 nm, respectively. The n-hexane adsorption was investigated using experiments and modelling. Eight adsorption isotherms along with three error functions were tested to model the adsorption equilibrium. The optimum sets of isotherm parameters were chosen by comparing sum of the normalized errors. The analysis indicated that the Freundlich isotherm gave the best agreement with the equilibrium experiments. In relation to different activated carbons, the adsorption capacity of TDAC for n-hexane is about 16.2 times higher than that of the worst reference material and 4.3 times lower than that of the best reference material. In addition, stereological analysis showed that activation with CO2 did not change the grain’s shape factors. However, a 25% increase in the mean particle cross-section surface area for TDAC was observed.

In the last few years, cationic layered clays, including bentonites have been investigated as potential catalysts for SCR DeNOx systems. In this work, bentonite as the representative of layered clays was modified in order to obtain an alternative, low-cost NH3–SCR catalyst. Samples of raw clay were activated with HCl or HNO3, treated with C2H2O4 and subsequently pillared with alumina by the ion- exchange. Afterwards, the modified materials were impregnated with iron and copper. The obtained catalysts were characterized by XRD and FT-IR. SCR catalytic tests carried out over analyzed samples indicated the conversion of NO of approximately 90% for the most active sample. The type of acid used for modification and the type of active phase strongly influenced the catalytic properties of the analyzed materials.

Catalytic properties of activated carbons oxidized, treated with N-compounds, and promoted with copper were studied in selective catalytic reduction NOX by ammonia (NH3-SCR). The modification of the catalysts consisted of a series of steps (pre-oxidation of activated carbon, impregnation with urea, impregnation with copper). The physicochemical properties of the obtained samples were determined using X-ray diffraction, FT-IR spectroscopy, and low-temperature N2 sorption. The modification with copper improved the catalytic activity and stability of the catalysts. All the functionalized carbon doped with copper reached more than 90% of NO conversion and CO2 did not exceed 240 ppm at 220 ◦C. The sample doped with 5 wt.% Cu had the maximum NO conversion of 98% at 300 ◦C. The maximum N2O concentration detected for the same sample was only 55 ppm, which confirmed its selectivity.

The paper presents a photographic analysis of the break-up of gas bubbles flowing out of the outlets of a self-aspirating disk impeller. It was found that bubbles detached from the interfacial surface most often disintegrate to form several daughter bubbles. Further in the work, the population balance model was verified for several formulas describing the bubble break-up rate. It has been found that a good fit to the experimental data is provided by the formula given by Laakkonen for 5 daughter bubbles. The possibility of using the Monte Carlo method to model the bubble break-up processwas also determined. For this method, a good agreement of results was achieved for the division into a maximum of 10 daughter bubbles. In the case of this method it was also found necessary to use the function of break-up frequency at a higher rate for smaller bubbles.

In this paper, three methods of sterilisation are compared to determine their usability in nanobubble dispersion sterilisation: filtration, thermal sterilisation and sonication (in two systems: using a sonotrode and sonication bath). Nanobubble dispersions are most commonly generated in non-sterile systems which precludes them from use in most biological research. As a result of this study, filtration was chosen as the best method for nanobubble sterilisation.