خسرو محمدی

Magnetic nano particles nanostarch (MNPs@NSt) are synthesized in the coprecipitation method. Then, magnetic nanocomposite particles supported by starch (MNPs@NSt@St) synthesized in order to biosorption of cupper ion. The synthesized MNPs@NSt and MNPs@NSt@St are investigated and identified by field emission scanning electron microscope (FE-SEM), x-ray diffraction (XRD), vibrating magnetic detector (VSM) and energy dispersion x-ray (EDX). The metal uptake, qe, as a function of pH, metal concentration, temperature, adsorbent dosage and contact time were investigated for MNPs@NSt@St. The optimum metal uptake was found pH=5.5, metal concentration=150 mg/L, 55 °C, adsorbent dosage = 2 g/L and contact time=60 minute. Also, the optimum conditions of cupper uptake with respect to multivariable parameters such as pH, temperature and metal concentration were calculated by response surface method (RSM) in Minitab software and fuzzy system in MATLAB software. The Toth and Marczewski–Jaroniec models were selected with respect to maximum regression (R2) and minimum sum square error (SSE) among the 15 isotherm models for describing the biosorption of cupper ion onto MNPs@NSt@St. Several types of kinetic models were investigated that the Fractal–like pseudo second order (FPSO) was the best pattern for describing the biosorption of cupper ion onto MNPs@NSt@St. Also, the thermodynamic variables (?H?, ?S? and ?G?) were calculated.