Performance Evaluation of Nanocomposit Magnetic Graphene Sheet- Iron Oxide in Removal of Nitrate from Water Using Taguchi Experimental Design

Background and Nitrate is one of the chemical water contaminants which can be eliminated through physical, chemical and biological techniques. In this study we aimed for optimization of nitrate adsorption from water onto Magnetic Graphene sheet Nano Particles (G-Fe3O4 MNPs) via Taguchi experimental design. Batch reactor was used for optimizing of the five parameters (pH, contact time, temperature, adsorbent dosage, and nitrate concentration) at four levels by Minitab software, based on Taguchi experimental design. Signal to noise ratio was used with ‘the highest is better’ approach for optimization of experimental conditions and the highest nitrate removal efficiency. The results revealed that in optimized status (pH=3, contact time= 60 min, initial concentration= 50 mg/L, adsorbent dose= 2g/L, temperature= 50oC) nitrate removal efficiency and adsorption capacity reached 86.4% and 39.37 mg/g, respectively. Contribution percentage of each variable implied that pH and initial concentration of nitrate with 40.20% and 7.49% had the highest and lowest influences on nitrate removal, respectively. Isotherm and kinetic studies illustrated that, nitrate adsorption complied with Langmuir isotherm model (R2>0.993) and pseudo second-order kinetics models (R2>0.94). G-Fe3O4 MNPs can be used as an effective sorbent for nitrate removal from water or wastewater due to several advantages including easy and rapid separation from solution and high removal efficiency.