Evaluating the effect of iron nanoparticles, pH, and initial dye concentration on the rate of dye removal in the treatment of wastewater containing acid yellow 36

Industrial dyes are among the stable materials that cannot be treated from wastewater by conventional methods and have persistent destructive effects on wastewater and environmental waters. Thus, it is crucial to find a suitable way to remove these substances. Acid yellow 36 is one of these industrial dyes. In the present study, the effect of nano-particulate zero-valent iron on the removal of this dye was investigated. To carry out this study, 30 experiments were designed using the experiment design software, and different laboratory conditions were applied using the information obtained from this design. Accordingly, the synthetic wastewater in different concentrations of initial dye was prepared and then the effect of nano-particulate zero-valent iron on the rate of removal of this substance from the water was investigated. The effect of parameters such as the number of Iron nanoparticles, initial dye concentration, and pH on the rate of dye removal was measured.  Among these parameters, pH was the most effective parameter and the best pH value for dye removal was 4 to 7.7, and values ​​higher than 7.7 and less than 4 reduced the dye removal efficiency. Very high concentrations of initial dye and low concentrations of nano-adsorbent also greatly reduced the removal efficiency.