Application of high order derivative spectrophotometry to resolve the spectra overlap between BG and MB for the simultaneous determination of them: Ruthenium nanoparticle loaded activated carbon as adsorbent

Because of technological importance of simultaneous analysis and removal of dyes in their mixtures, we studied the competitive adsorption of brilliant green (BG) and methylene blue (MB) dyes onto Ruthenium nanoparticles on activated carbon (Ru/C). Due to overlap between the spectra of the dyes, it was needed to apply a suitable method to resolve this overlap. Recently, first derivative method was successfully used to study binary solutions. However, it was failed to apply for the binary solution of BG and MB. Therefore, we successfully applied high order derivative spectrophotometry for resolving the spectra overlap between BG and MB and for the simultaneous determination of them in their mixture. The presence of multi-solute pollutants in most industrial wastewater necessitates investigating the effect of multi-solute systems on adsorption capacity. The optimal pH at which the adsorption capacity is maximum, was found to be close to the pH of natural aqueous solutions that is an advantage. A low dosage (0.015 g) of the prepared carbon-supported Ru nanoparticles (Ru/C) with high surface area (1266 m2/g according BET) was efficiently used for the dyes removal at pH 6.0 (close to the pH of natural aqueous solutions) and at room temperature that is an advantage of Ru/C. Isotherm constants were obtained for BG and MB after modeling experimental data by using different isotherms. A better consistency to Freundlich isotherm model was found. Thermodynamic parameters showed an endothermic and a spontaneous nature for the adsorption of the dyes.