Adsorption Potential of Iron-Zirconium Oxide Nanoparticles for 3-Chlorophenol and 3-Nitrophenol: Thermodynamic, Kinetic, and Mechanistic Studies

Iron-zirconium oxide nanoparticles (IZO-NPs) have displayed enhanced adsorption capabilities for 3-chlorophenol (3-CPh) and 3-nitrophenol (3-NPh). The adsorption behavior is notably influenced by pH, with pH = 4 demonstrating optimal adsorption. Langmuir constants X_m and K_L were precisely determined under optimized conditions. The adsorption mechanism of 3-CPh and 3-NPh on IZO-NPs is attributed to weak van der Waals interactions. Notably, the Langmuir adsorption isotherm exhibited superior conformity to the adsorption trends compared to the Freundlich and Temkin models. The adsorption capacity (X_m) for 3-CPh and 3-NPh on IZO-NPs was quantified at 384.61 and 416.66 mg/g, respectively. Thermodynamic analyses conducted within the temperature range of 288 to 333 K revealed the values of ΔH°, ΔS°, and ΔG°. These thermodynamic properties indicated that the adsorption of 3-CPh and 3-NPh on IZO-NPs is an exothermic and spontaneous physicochemical process rather than a purely physical or chemical one. Furthermore, the adsorption process was determined to follow a pseudo-second-order kinetics model based on kinetic studies. This implies that the control mechanism governing the adsorption process in this investigation is characterized by a pseudo-second-order reaction.