RESEARCH ON THE MECHANISM OF MELANOIDIN ADSORPTION KINETICS FROM AQUEOUS SOLUTIONS BY CARBONIC ADSORBENTS

Abstract

Melanoidins are widely used in food and pharmaceutical industries. Melanoidins, which get in water bodies with wastewater of plants, pollute them, which subsequently can have a negative impact on the population health. Wastewater treatment of plants is an important condition to preserve the integrity of aquatic ecosystems. Sorption filtration is the most effective way of removing organic substances among the methods, used for wastewater treatment. To study the adsorption kinetics, the carbonic sorbents of the brands ABG and Purolat-Standard were used, which differ with a raw material, a surface chemistry state and a porous structure. The study of the adsorption kinetics allows to determine the mechanism of mass transfer in the system adsorbent-adsorbate and to obtain the parameters, necessary for engineering evaluation of adsorption processes in practice. It is shown that the time of reaching equilibrium in the sorption system varies in the range of 150-250 minutes. The degree of reaching the adsorption equilibrium () and the dimensionless kinetic parameters T have been calculated, which are proportional to the time of the process (t). It is found that the melanoidin adsorption rate is controlled by external mass transfer, necessary for calculation of optimum parameters and modes of the adsorption process. Experimental research allows to determine that the granules of the used carbonic sorbents interact with the dissolved substance in the full volume and throughout the particle is in the reaction zone; such interaction relates to a quasi-homogeneous model. It is shown that at the melanoidin adsorption, the rate of the internal diffusive mass transfer depends on the porous structure of the carbonic adsorbents. A high value of the external mass transfer coefficient for the carbonic sorbent Purolat-Standard suggests a high degree of melanoidin extraction from aqueous solutions.