Author/Authors :
Khazaei، Mohammad Rasool نويسنده Fertility and Infertility Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran , , Nasseri، Simin نويسنده 1Department of Environmental Health Engineering, School of Public Health and Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran , , Ganjali، Mohammad Reza نويسنده , , Khoobi، Mehdi نويسنده Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14176, Iran , , Nabizadeh، Ramin نويسنده Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran , , Mahvi، Amir Hossein نويسنده Department of Environmental Health Engineering, School of Health; National Institute of Health Research; Center for Solid Waste Research, Institute fo , , Nazmara، Shahrokh نويسنده 1Center for Environmental Research and Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran , , Gholibegloo، Elham نويسنده Department of Chemistry, Faculty of Science, University of Zanjan ,
Abstract :
Background: Magnetic graphene oxide (Fe3O4@SiO2-GO) nanocomposite was fabricated through a facile process and its application as an excellent adsorbent for lead (II) removal was also demonstrated by applying response surface methodology (RSM). Methods: Fe3O4@SiO2-GO nanocomposite was synthesized and characterized properly. The effects of four independent variables, initial pH of solution (3.5–8.5), nanocomposite dosage (1–60 mg L?1), contact time (2–30 min), and initial lead (II) ion concentration (0.5–5 mg L?1) on the lead (II) removal efficiency were investigated and the process was optimized using RSM. Using central composite design (CCD), 44 experiments were carried out and the process response was modeled using a quadratic equation as function of the variables. Results: The optimum values of the variables were found to be 6.9, 30.5 mg L?1, 16 min, and 2.49 mg L?1 for pH, adsorbent dosage, contact time, and lead (II) initial concentration, respectively. The amount of adsorbed lead (II) after 16 min was recorded as high as 505.81 mg g?1 for 90 mg L?1 initial lead (II) ion concentration. The Sips isotherm was found to provide a good fit with the adsorption data (KS=256 L mg?1,n S=0.57, qm=598.4 mg g?1, and R2=0.984). The mean free energy Eads was 9.901 kJ/mol which confirmed the chemisorption mechanism. The kinetic study determined an appropriate compliance of experimental data with the double exponential kinetic model (R2=0.982). Conclusions: Quadratic and reduced models were examined to correlate the variables with the removal efficiency of Fe3O4@SiO2-GO. According to the analysis of variance, the most influential factors were identified as pH and contact time. At the optimum condition, the adsorption yield was achieved up to nearly 100 %.
