title: Mercury removal from aqueous solutions with chitosan-coated magnetite nanoparticles optimized using the box-behnken design.
abstract: BACKGROUND
  Nowadays, removal of heavy metals from the environment is an important problem due to their toxicity.
  
  
  OBJECTIVE
  In this study, a modified method was used to synthesize chitosan-coated magnetite nanoparticles (CCMN) to be used as a low cost and nontoxic adsorbent. CCMN was then employed to remove Hg(2+) from water solutions.
  
  
  METHODS
  To remove the highest percentage of mercury ions, the Box-Behnken model of response surface methodology (RSM) was applied to simultaneously optimize all parameters affecting the adsorption process. Studied parameters of the process were pH (5-8), initial metal concentration (2-8 mg/L), and the amount of damped adsorbent (0.25-0.75 g). A second-order mathematical model was developed using regression analysis of experimental data obtained from 15 batch runs.
  
  
  RESULTS
  The optimal conditions predicted by the model were pH = 5, initial concentration of mercury ions = 6.2 mg/L, and the amount of damped adsorbent = 0.67 g. Confirmatory testing was performed and the maximum percentage of Hg(2+) removed was found to be 99.91%. Kinetic studies of the adsorption process specified the efficiency of the pseudo second-order kinetic model. The adsorption isotherm was well-fitted to both the Langmuir and Freundlich models.
  
  
  CONCLUSIONS
  CCMN as an excellent adsorbent could remove the mercury ions from water solutions at low and moderate concentrations, which is the usual amount found in environment.
authors.affiliation: Nanotechnology Research Center, Jundishapur University of Medical Sciences, Ahvaz, IR Iran ; Department of Medicinal Chemistry, School of Pharmacy, Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Nadereh
authors.initials: N
authors.lastname: Rahbar
authors.affiliation: Nanotechnology Research Center, Jundishapur University of Medical Sciences, Ahvaz, IR Iran ; Department of Medicinal Chemistry, School of Pharmacy, Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Jahangiri
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Shahin
authors.initials: S
authors.lastname: Boumi
authors.affiliation: Department of Pharmacology and Toxicology, Toxicology Research Center, School of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Khodayar
keywords: Chitosan; Magnetite Nanoparticles; Mercury