Adsorption Properties Of Iron-Loaded Composite Resin For Chromium (Vi)

Removal of Cr(VI) from liquid by iron-loaded composite resin was studied. The isothermal adsorption model and the adsorption kinetic model were established. The adsorption thermodynamic parameters were solved. The iron-loaded composite resins before and after adsorption were characterized by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). It was found that the adsorption capacity of iron-loaded composite resin was higher than others. The results showed that the optimum adsorption condition was performed at 318 K, the pH of 2, and the time of 6 h. Freundlich model and pseudo-first-order kinetic model fitted the experimental data. The main control step of the adsorption was liquid film diffusion process. The value of Delta H was 2-16 kJ mol(-1), which showed that the adsorption was an endothermic process. The adsorption of Delta G was less than zero which indicated the adsorption was spontaneous. The value of Delta S was constant positive that revealed the adsorption was the total entropy-increasing process. SEM and EDS analyses indicated that Cr(VI) can adsorb by iron-loaded composite resin effectively. The eluent of 6% NaOH + 5% NaCl had an excellent desorbing performance.