The sorption of Cd(II) from aqueous solutions by fixedLentinus edodesmushroom flesh particles

Abstract

Abstract Lentinus edodes residue that is immobilized with polyvinyl alcohol–Na-alginate was studied as a sorbent for Cd(II) removal from solutions to discover a cost-effective and more practical sorption material for heavy metal ion removal from sewage. Results demonstrated that the sorption of Cd ions by immobilized L. edodes reached equilibrium within 7 h. The kinetics of Cd ion sorption were best described with a pseudo-second-order model with an equilibrium sorption capacity (q e) of 0.2008 mg/g. The optimal pH for Cd ion sorption ranged from 4 to 7. The sorption capacity for Cd ions gradually increased with increasing initial Cd concentration from 0 to 120 mg/L. When the Cd ion concentration was fixed at 10 mg/L and the interfering metal Cu or Pb ion concentration in the same solution was varied from 0 to 30 mg/L, the sorption rate of Cd ions decreased significantly, as determined with variance analysis. The Langmuir model was the most suitable for describing Cd ion sorption with a correlation coefficient (R 2) of 0.9981 and a theoretical maximum sorption capacity (q m) of 6.4475 mg/g, which was similar to the experimentally observed q m of 6.046 mg/g. The Langmuir–Freundlich and Freundlich models were also suitable for describing the Cd ion sorption process. Scanning electron microscopy was used for observing the contractive change of the cell surface before and after absorbing Cd ions by immobilized L. edodes beads. Fourier transform infrared spectroscopy analysis demonstrated –OH, –CO, and –CO–NH in the cell wall of L. edodes plays an important role in Cd ion sorption.