Mladen Eić

The microwave-assisted dry reforming of methane over Ni and Ni–MgO catalysts supported on activated carbon (AC) was studied with respect to reducing reaction energy consumption. In order to optimize the reforming reaction using the microwave setup, an inclusive study was performed on the effect of operating parameters, including the type of catalysts’ active metal and their concentration in the AC support, feed flow rate, and reaction temperature on the reaction conversion and H₂/CO selectivity. The methane dry reforming was also carried out using conventional heating and the results were compared to those of microwave heating. The catalysts’ activity was increased under microwave heating and as a result, the feed conversion and hydrogen selectivity were enhanced in comparison to the conventional heating method. In addition, to improve the reactants’ conversion and products’ selectivity, the thermal analysis also clarified the crucial importance of microwave heating in enhancing the energy efficiency of the reaction compared to the conventional heating.

The aims of this work were to prepare porous activated carbon from peanut shell by chemical activation using ZnCl₂ and study its volatile organic compounds adsorption capacities. The adsorption properties of ethyl on the prepared activated carbon were experimentally determined at different temperatures. The surface textural characteristic of the activated carbon was evaluated by N₂ adsorption isotherm measurements. The average BET surface area, pore size, and micro‐pore volume of the prepared activated carbon were 1025 m²/g, 0.70 nm, and 0.37 cm³/g, respectively, with narrow pore size distribution. Higher adsorption capacity of toluene on the activated carbon was observed compared to ethyl benzene and p‐xylene, in particular at low vapour concentration ranges. The experimental isotherm data were also analyzed using the Langmuir, Langmuir‐Freundlich, and multisite Langmuir isotherm model. The Langmuir‐Freundlich and multisite Langmuir model provide the best fit for volatile organic compound adsorption isotherms. In addition, the surface and thermal properties of the activated carbon were also investigated using FT‐IR, Zeta‐potential, and TGA. Overall, the peanut shell activated carbon prepared in this study exhibited comparable surface properties and adsorption performance with the available commercial activated carbons and activated carbons prepared from other various sources reported in other literature.

The comprehensive study involving uptake and kinetics behaviour of methane and ethane was carried out on a commercial carbon molecular sieve. The gravimetric technique was applied to measure the adsorption isotherms at different temperatures. The kinetic behaviours of methane and ethane were investigated by extracting the uptake data from isotherms at different pressure steps. Considering CMS as a homogenous microporous adsorbent, only two main resistances: surface barrier (at the pore mouth) and diffusion resistance (inside the pores) were considered in analysing the kinetic data. The kinetic analysis showed dominance of surface barrier resistance at all temperatures and pressures investigated in this study. Modified Darken equation was used to calculate the sorbates’ activation energies for adsorption in CMS pores. Compared to Darken equation, the modified Darken model predicted the concentration dependency of the surface rate constants more accurately, especially at higher sorbates’ concentrations. The activation energy of methane and ethane was greater than the heat of adsorption demonstrating a large impedance and barrier at the pore surface to the methane and ethane molecules. The kinetic selectivity of methane over ethane was calculated from the combined surface barrier/diffusion model parametric analysis. The results generally showed a greater selectivity to methane over ethane, i. e., the higher mass transfer rates.