Batch Equilibrium, Kinetics and Thermodynamics Study of Sulfamethoxazole Antibiotics Onto Azolla filiculoides as a Novel Biosorbent

Azolla filiculoides (AF) were used as adsorbent for the sorption of Sulfamethoxazole (SMZ) from aqueous solution. Also adsorption Isotherms, kinetics and thermodynamics were studied. Experiments were conducted by varying parameters such as contact time, agitation speed, initial SMZ concentration and temperature. Adsorption isotherms models including Langmuir, Freundlich and Temkin were tested. It was inferred that the Langmuir models (with very high R2 values) were most suited to describe the sorption of SMZ in aqueous solutions. The experimental data were fitted into the following kinetic models: Pseudo-first-order, pseudo-second-order, and the intraparticle diffusion model. It was observed that the pseudo-second-order kinetic model described the adsorption process better than other kinetic models. Thermodynamic parameters including the Standard free energy changes (△G◦), standard enthalpy change (△H◦), and standard entropy change (△S◦) were calculated. This parameters indicated that the adsorption of SMZ onto AF biomass was feasible, spontaneous and endothermic. This study revealed that AF biomass is a good adsorbent for the elimination of Sulfamethoxazole antibiotics from aqueous solution.