مطالعه ایزوترم و کینتیک جذب کروم شش ظرفیتی بر روی دانه های آلژینات کلسیم در محلولهای آبی

One of the most important environmental problems is water and soil contamination with heavy metal ions. In this direction, the aim of this investigation was biosorptive removal of Cr (VI) using calcium alginate and determination of isotherm and kinetic of biosorption. Materials and Methods: Using batch system, biosorption capacity of calcium alginate for removal of Cr(VI) ions was investigated as function of pH, shaking time and Cr(VI) ions concentration. For determination of active bands and biosorbent characteristic, Fourier Transform Infrared (FT-IR) and Scanning Electron Microscopy (SEM) analysis were carried out respectively. Results: Regarding the FT-IR analysis, It was shown that C=O and O–H groups played a significant role in Cr (VI) biosorption onto alginate calcium. The optimum pH was obtained at pH value of 4.0. Suitable fitness between the experimental data and studied isotherm was obtained (R2>0.9). Maximum biosorption capacity of calcium alginate was 84.75 mg/g. The mean free energy of Cr(VI) biosorption (E) was calculated 9.129 kJ/mol. Moreover, the pseudo-second order kinetic model was found to be suitable than the pseudo-first order kinetic model to correlate the experimental data (R2>0.97) and equilibrium was achieved within 120 min. Conclusion: It can be stated that biosorption of Cr (VI) onto calcium alginate occurs through a chemical mechanism. Also, according to maximum biosorption capacity, it can be stated that calcium alginate is an effective and efficient biosorbent.