Plackett-Burman Design for Optimizing Toluene Adsorption from Air Using Zinc Oxide Nanoparticles: Kinetics and Isotherm Studies

In this research, zinc oxide (ZnO) nanoparticles were synthesized and investigated as adsorbents for the removal of vapors of toluene from air samples. The synthesized adsorbent was characterized by using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Adsorption efficiency was measured using Gas Chromatography (GC). A Plackett-Burman design (PBD) was employed to identify the significant factors affecting the adsorption process, including the temperature of the solution, adsorbent dosage, and initial concentration, Optimization of important parameters was performed using Response Surface Methodology (RSM), which achieved a maximum toluene removal efficiency of 93.98% which represented good agreement with experimental results of 93.1%. The highest adsorption efficiency for toluene was obtained at 75.5 ˚C with its initial concentration of 247 mg/ L and ZnO adsorbent dosage of 9.73 mg. Adsorption kinetics and isotherm studies revealed that the process follows a Langmuir isotherm that indicated monolayer adsorption and a pseudo-second-order with chemical interaction. The study concludes that porous ZnO nanoparticles are highly effective for toluene removal from air, providing a cost-efficient and scalable solution for air purification in industrial and environmental applications.