EXPERIMENTAL STUDY AND MODELING OF ADSORPTION KINETICS OF PHARMACEUTICAL MOLECULES ON ACTIVATED CARBONS

The contamination of water systems with pharmaceutical products and synthetic chemicals is one of the most significant environmental concerns. Current research emphasizes on the design and development of materials able to remove a large variety of chemicals from wastewater effluents and natural water compartments. In this context, adsorption is considered a promising alternative as it removes a wide variety of organic and inorganic compounds and generates less toxic products than many other remediation methods. The present work is devoted to the preparation of an activated carbon from agricultural waste for the adsorption of paracetamol in aqueous solution. Adsorption kinetics and isotherms were studied in aqueous solution at self-equilibrium pH. Pseudo-first-order and pseudo-second-order kinetic models were tested to determine adsorption kinetic parameters. Empirical models are used to model the isotherm (Langmuir and Freundlich) with the aim of calculating the maximum sorption capacity of coal (ACW), and establishing a mechanism for the adsorption process. Pseudo-second-order and Langmuir models proved adequate for interpreting experimental results. Thermodynamic parameters characterizing adsorption showed that the process is spontaneous (ΔG° < 0) and exothermic (ΔH°< 0), with a physical interaction between the adsorbate and adsorbent (ΔH°<20 kJ/mol).

In light of the results obtained in the course of this work, we can conclude that the carbon synthesized in this way is an excellent adsorbent material with a high affinity for paracetamol. It also offers a number of advantages, such as low cost and good availability of the raw material, as well as easy access to the charcoal via a simple preparation process.