4.5. Investigation of the effect of methylene blue dye solution concentration
To investigate the effect of methylene blue solution concentration on the removal from dye wastewater, at first, solutions of different concentrations (10, 30, 50 ppm) were prepared. 100 ml sample was taken from each sample and 0.1gr of nanocomposite (NiFe2O4@SiO2) @HKUST-1) (30%) was added in the presence of oxygenated water and again under ultrasound for better mixing. after 10 minutes, samples were collected and centrifuged, and the amount and removal efficiency were calculated using a spectrophotometer.
Fig (17): Diagram of the effect of dissolved concentration on the degradation of methylene blue dye.
It can be seen in Fig 17 that the removal efficiency in methylene blue aqueous solution at 10 ppm concentration had the highest removal efficiency. So that after 60 minutes about 95% removal was done. However, for methylene blue dye solution with concentration (30 and 50 ppm), the removal efficiency reached (62.4% and 59.03%). This indicates that the removal efficiency decreased with increasing concentration of methylene blue dye solution. The reason for this decrease is that as the concentration of the dye solution increases, the dye molecules in the solution increase and given the constant concentration of the nanocomposite metal-organic framework synthesized in these solutions, the active sites and specific surface area of the nanocomposites are completely saturated and filled. As a result, the lower the concentration of the dye solution, the less the dye molecule in the solution so pore volumes and surface areas will be filled in a longer time and their removal efficiency will be higher.