Abstract

Heavy metals pollution in the environment is one of the serious problems in the field of water and wastewater management. In this study; calcium carbonate nanoparticles, synthesized by an efficient and novel method, were used as an adsorbent for the removal of lead and iron from aqueous solutions. To study the mechanism of adsorption, the kinetic and isotherm models were examined. The adsorption kinetics of process was found to follow a pseudo-second-order equation. The maximum monolayer adsorption capacities of calcium carbonate nanoparticles calculated from Langmuir isotherm were found to be 1210±30 mg/g for Pb(II) and 845±8 mg/g for Fe(II) ions, respectively. The response surface methodology based on three variable Box-Behnken design was utilized to evaluate the effects of temperature (25-65 oC) and initial metal concentration (10-200 mg/L) on the sorption process. The optimum conditions for the removal process using calcium carbonate nanoparticles were found to be 200 mg/L at 25 oC. Experimental data demonstrated that a precipitation transformation mechanism rather than adsorption enhances the removal efficiency.

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