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. Objectives: 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. Materials and 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.

Cerium functionalized PVA–chitosan composite nanofibers for effective remediation of ultra-low concentrations of Hg(ii) in water

“…It has also been reported that at pH 5-6, the presence of the amino group in CHT (pK a ¼ 6.5) becomes protonated, and H + ions are produced in the presence of HCl, which leads to formation of anion complexes such as HgCl 3 À1 . This anion is adsorbed on Ce-PVA-CHT composite nanobers 18,47 by a complex formation with amino and Ce present in composite nanobers. No signicant change in the pH value of the solution before and aer Hg(II) adsorption was observed.…”

Application of response surface methodology for Cd(II) adsorption on maize tassel-magnetite nanohybrid adsorbent

“…In an endeavour to overcome the problems, recent research has been shifted to preparing magnetic adsorbents by inducing magnetic particles [18][19][20][21][22]. Magnetic adsorbents have been reported to have high surface/volume ratios, chemical stability, biocompatibility, and excellent magnetic properties and can be easily separated from the aqueous solution by using an external magnetic field [23]. The unique properties of magnetic induced adsorbents provide a plethora of ideas to solve problems in adsorption technology.…”

“…Furthermore, scale-up of the process is difficult since it requires a number of experiments to get the optimum levels thereby resulting in a costly process [24]. All the process independent variables can be optimized collectively by applying a response surface methodology (RSM), a mathematical statistical technique which optimizes the process and evaluates the relationship between a set of independent variables [18,[23][24][25][26]. Moreover, it evaluates the relative significance of the various independent variables even in the presence of complex factorfactor interactions [27].…”

Comparative and competitive adsorption of Cu(II), Cd(II) and Pb(II) onto Sepia pharaonis endoskeleton biomass from aqueous solutions

“…However, the Freundlich isotherm describes the metal adsorption in a heterogeneous system and is not restricted to the monolayer formation (Rahbar et al . ). The linear graphs of the Langmuir and Freundlich isotherms were plotted for each ion and the parameters of adsorption isotherms are shown in Table (Supporting Information Figs S4 and S5).…”