Kinetic, equilibrium, and thermodynamic study on atrazine adsorption in organophilic clay

The organophilic clay used as adsorbent in this work was obtained from the modification of the commercial Fluidgel clay with the hexadecyltrimethylammonium bromide salt by the chemical synthesis process. The commercial and modified adsorbent materials were characterized by N-2 physics, scanning electron microscopy (SEM), thermal analysis (TGA/DTA), X-ray diffraction (XRD), energy dispersive system (EDX), and Fourier-transform infrared spectroscopy (FTIR), aiming to determine possible structural, morphological, structural, and chemical changes promoted by the organophilization stage. The kinetic, equilibrium, and thermodynamic aspects of the atrazine adsorption process were investigated by using the synthesized material. In the optimization of the parameters, it was verified that the pH did not influence significantly the adsorption. The kinetic model that best represented the data was that proposed by Elovich and through the equilibrium isotherms and thermodynamic analysis, it was verified that the material has heterogeneous active sites and that the process is favorable, reaching maximum values of adsorption capacity of up to 3.492 mg g(-1), thus highlighting the good performance of the material when compared with other alternative adsorbents in the removal of atrazine in contaminated water.