Adsorption of hexavalent chromium on manganese nodule leached residue obtained from NH3–SO2 leaching

Adsorption of hexavalent chromium onto manganese nodule leached residues was investigated as a possible alternative to the conventional methods of its removal from aqueous synthetic solutions. Adsorption behavior was studied as a function of time, pH, temperature, and concentration of adsorbate and adsorbent in acetic acid–sodium acetate buffer medium. Cr (VI) removal was pH dependent and was found to be of a maximum at pH 3. The applicability of the Langmuir isotherm to the present system was tested. Increased adsorption capacity with increased temperature indicates that the adsorption reaction was endothermic in nature. Based on these studies, thermodynamic parameters such as Gibbs free energy change (ΔG0ΔG0), standard enthalpy change (ΔH0ΔH0), and standard entropy change (ΔS0ΔS0) were calculated.

Graphical abstractManganese nodule leached residue is a waste, which can be used as an effective adsorbent for removal of hexavalent Cr (80%) from aqueous solution at pH 3.Figure optionsDownload full-size imageDownload as PowerPoint slide