Facile isotherms of iron oxide nanoparticles for the effectively removing organic and inorganic pollutants from landfill leachate: Isotherms, kinetics, and thermodynamics modelling

Landfill leachate is obstinate wastewater due to the presence of various organic and inorganic pollutants. In this study, iron oxide (Fe2O3) nanoparticles were isolated from iron ore for use as adsorbents to eliminate chemical oxygen demand (COD), color, and ammoniacal nitrogen (NH3–N) from landfill leachate. The efficiency of this process was determined by varying the pH, adsorbent dosage (g/L), contact time (min), and heat level (°C). The results showed that the Fe2O3 nanoparticles could effectively remove more than 70% of COD, 60% of NH3–N, and an estimated 98% of color from landfill leachate. The Langmuir and Freundlich isotherm models were employed to determine the adsorption equilibrium behavior of Fe2O3 nanoparticles for eliminating COD, color, and NH3-N. The Langmuir isotherm model was found to be the most effective for the aforementioned process. Kinetic studies indicated that the elimination of COD, NH3–N, and color fitted well with the pseudo-second-order kinetic model. The thermodynamic properties were determined through analysis, indicating that the removal of COD, NH3–N and color from landfill leachate using the Fe2O3 nanoparticles occurred spontaneously and endothermically. This research indicates that Fe2O3 nanoparticles can be utilized as adsorbents for effectively removing both organic and inorganic pollutants from landfill leachate.