The equilibrium and kinetics studies of flurbiprofen adsorption onto tetrabutylammonium montmorillonite (TBAM)

In this study, the adsorption of flurbiprofen (FBP, is a non-steroidal anti-inflammatory drug) on tetrabutylammonium (TBA)-montmorillonite (TBAM) was studied. The adsorption kinetics was interpreted using pseudo-first-order kinetic model and pseudo-second-order kinetic model. The pseudo-second-order model provides the best correlation with the experimental data of TBAM adsorption. The adsorption data could be fitted with Freundlich and Dubinin-Radushkevich equation to find the characteristic parameters of each model. The adsorption energy, E and adsorption capacity (qm) for organic compound adsorbing on organo montmorillonite were estimated using the Dubinin-Radushkevich (D–R) equation. From DR isotherm, it was also determined that the type of adsorption can be considered as physical adsorption mechanism. Thermodynamic parameters (Δga = −1.897 and −3.456 kJ/mol, Δha = −28.722 and −30.948 kJ/mol, Δsa = −0.0964 and −0.0989 kJ/mol °K for 298 and 313 °K, respectively) were calculated by a new approximate from the adsorption isotherms of FBP on organo montmorillonite. The first order and second order coefficients (K1ads = 2.50 and 14.30 mmol/g min, K2ads = 0.0130 and 0.03120 g min/μmol,respectively) were obtained at 298 and 313 K, respectively.