Synthesizing non-toxic adsorbent for abatement of hazardous pollutants from water is important to develop safe environment. In this study, nanocrystalline iron oxide particles were synthesized and utilized as effective nanoadsorbent for removing cadmium through adsorption. The as-prepared nanoadsorbent was characterized using sophisticated techniques. The objective of this study was to improve cadmium adsorption from aqueous solutions under a variety of conditions. With the help of Box-Behnken design, adsorption parameter settings were improved. Response Surface Methodology analysis was conducted to optimize the adsorption conditions, including pH, initial concentration of metal ions, and adsorbent dose. Comparisons were made between the optimal equations for linear and non-linear kinetics, along with isotherm models. Origin's curve fitting tool and the Solver add-in of Microsoft Excel are two non-linear analytical tools. The obtained results showed that the Origin curve fitting tool is superior to solver add in's error analysis method for determining isotherm parameters. The equilibrium data for cadmium removal using nano iron oxide/hydroxide adsorbent was best fitted to Langmuir isotherm model. The adsorption of cadmium was well described by the pseudo-second-order model. The study shows that the system appears to be spontaneous according to the Langmuir constant method and thermodynamic parameter via partition.
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