A study on the adsorption capacity of carbon materials obtained from different plant raw materials

Abstract

The aim of the work was to investigate the possibilities of obtaining activated carbon materials (AC) with controlled nanoporosity dependent on the raw materials used by involving an innovative method of its production and confirming the effect of reducing the density of the liquid under the action of the adsorption potential of the pore walls by means of modeling by the Boltzmann lattice method within the framework of a two-dimensional model. The results of the study showed that depending on the raw material used (chips of various hardwood species) and the method of its primary processing (involving an innovative method of its production, shear deformation, in particular), it is possible to obtain AB with a different ratio of micro- and mesopores, from almost completely microporous samples to samples with developed mesoporosity. It is shown that during carbonization, the organic matter that blocked the pores of the tubular structure is removed, forming open holes. Data infrared (IR) Fourier spectroscopy confirm that the formed surface of the micro-mesoporous sorbent must actively interact with polar and non-polar adsorbates with the help of surface functional groups, which corresponds to the results obtained in the work on the structural and sorption parameters of AB. The liquid density distribution along the pore axis of the mesoporous matrix was calculated by modeling using the Boltzmann lattice method, dependent on the initial wetting angle and capillary size. It is shown that in nanopores of small size (10 nm) the density of the liquid phase gradually decreases and at a certain depth of the pore its jump-like drop occurs, which reflects the presence of a phase transition to intense vaporization. So, the mechanism of purification of aqueous solutions from harmful impurities by nano-sized pores due to the effect of reducing the density of the liquid under the action of the adsorption potential of the pore walls has been confirmed. The micro-mesoporous AB obtained in the work can be used for the production of a wide range of matrix and composite materials with controlled nanoporosity. They are promising sorption materials, as they are characterized by lower diffusion complications during adsorption. And the effect of reducing the density of the liquid under the influence of the adsorption potential of the pore walls well explains the possible mechanism of cleaning contaminated aqueous liquids with the help of a mesoporous matrix.