4.2 The effect of MOF concentration on dye removal
To investigate the effect of MOF concentration on the removal of methylene blue dye, a dye solution (10 ppm) was first prepared. Then different concentrations of 30% metal-organic framework (NiFe2O4@SiO2@HKUST-1) nanocomposite were added to the solutions and mixed with ultrasonic water in the presence of oxygenated water. Then, every 10 minutes, samples were taken, and the wavelengths were measured using spectrophotometer analysis. Figure (15) shows the removal of methylene blue dye using different concentrations of 30% nanocomposite (NiFe2O4)@SiO2@HKUST-1.
Fig (16): Diagram of the effect of different concentrations nano composite on methylene blue degradation.
As can be seen in Fig (16), at low concentrations the removal process proceeds slowly but with increasing nanocomposite concentration ((NiFe2O4@SiO2@ HKUST-1) 30%) the dye removal is faster. So that for 0.1 gr concentration of nanocomposite was removed 95% after 60 min and for each concentration 0.03 and 0.06 gr after 70 min removal, 48% and 73.5% respectively was observed. Therefore, it can be concluded that by increasing the concentration of nanocomposites, dye removal is shorter and removal efficiency increases. This increase in efficiency is due to the increased concentration of nanocomposite in the metal-organic framework of the special active surface in the solution, thus more dye molecules can be incorporated into these active sites, which increases the removal efficiency of the dye.