Efficient Cr(VI) and phosphate removal from contaminated water using MnTiFeO nanoflakes: Statistical modeling and interpretation

MnTiFeO nanoflakes (NF) have been prepared and used to remove Cr(VI) and phosphate from an aqueous solution. The optimum potentials for adsorption of Cr(VI) and phosphate occur at acidic pH and are primarily due to ionic interactions. Langmuir monolayer adsorption is observed. The active sites of NF show some selectivity for Cr(VI) due to various putative interaction modes. The adsorption of Cr(VI) and phosphate are dominated by a multi-docking process, as implied by steric parameters in applied advanced statistical models. The observed selectivity of NF is primarily due to a higher receptor site density for Cr(VI) ions than for phosphate anions. Statistical modeling yields the best fitting of the experimental data for a double-layer in the binary system. MnTiFeO NF can be regarded an effective, competitive, and low-cost adsorbent for the removal of hexavalent Cr and phosphate. The maximum adsorption capacities of MnTiFeO NF for Cr(VI) and phosphate adsorption were evaluated as 166.66 and 163.93 mg/g, respectively.