Preparation of a Modified Nanoalumina Sorbent for the Removal of Alizarin Yellow R and Methylene Blue Dyes from Aqueous Solutions

A modified form of gamma-alumina nanoparticles prepared by immobilization of 2,4-dinitrophenyl hydrazine on gamma-alumina nanoparticles coated with sodium dodecyl sulfate (DNPH-gamma-alumina) for the removal of the anionic dye (Alizarin yellow R) and cationic dye (Methylene blue) from aqueous solutions has been investigated. The FTIR, SEM, TEM, XRD, BET, and BJH analysis techniques indicate that the modification reaction has occurred. Batch adsorption study revealed that 0.05 g amount of the modified adsorbent was capable of removing 95.6% and 65.6% of Alizarin yellow (AY) and Methylene blue (MB) dyes, respectively, in 60 min. The experimental equilibrium data showed that Langmuir isotherm applies well for describing the adsorption behavior, and the maximum adsorption capacity was found to be 47.8 mg/g and 32.8 mg/g for AY and MB on DNPH-gamma-alumina, respectively. Kinetic studies showed best applicability of the second-order kinetic model. The DNPH-gamma-alumina adsorbent proved capability, effectiveness, and selectivity for the removal of Alizarin yellow R dye. Therefore, it is possible to increase the efficiency of an adsorbent for the removal of pollutants by applying a modification to the surface of the adsorbent, and DNPH as a modifier proved efficient for the removal of a wider range of pollutants including metal ions and dye compounds.