Optimizing adsorption of Cr(VI) from aqueous solutions by NiO nanoparticles using Taguchi and response surface methods

In the present study, nickel oxide nanoparticles synthesized by the sol–gel method were used as an effective adsorbent for the removal of Cr(VI) from aqueous solutions. To do so, the effect of four parameters including the concentration of Cr(VI), the dosage of NiO, contact time, and pH on the removal of Cr(VI) by NiO nanoparticles were studied. In order to examine and describe the optimum conditions for each of the mentioned parameters, Taguchi and response surface methods were used. The results of the experiment using Taguchi and response surface methods indicated the greater effect of the NiO adsorbent parameter in comparison to the other parameters in the adsorption of Cr(VI) by NiO nanoparticles, and showed that the increase in contact time and pH does not affect the removal percentage of Cr(VI) significantly.