The adsorption of methylene blue from wastewater by Moringaoleifera pods and kernels wastes using the response surface methodology

In recent decades, researchers have focused more on the use of many types of biomaterials from various organisms and agricultural by-products for wastewater treatment. In this study, we are using Moringaoleifera pods powder (MOPP) and Moringaoleifera kernels powder (MOPK) for the removal of industrial Methylene blue (MB) dye from aqueous solutions. The adsorption process of MB onto MOPP and MOKP follows the pseudo-second-order model. First of all, the adsorbents were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscope (SEM). The second objective was the optimization process of Moringaoleifera wastes seeds (MOPP and MOKP) for the removal of methylene blue dye (MB), using Box-Behnken under the Response Surface methodology. The optimal conditions were X-1 = 2.5 g/L of adsorbent, X-2 = 40 ppm of concentration of MB and X-3 = 10.03 of pH with removal efficiency which reaches 98.12% for MOPP and X-1 = 2.5 g/L of adsorbent, X-2 = 30 mg/L of concentration of MB and X-3 = 7.43 of pH with removal efficiency which reaches 96.94% for MOKP. The model envisaged for the optimal design has been well verified by the experimental data, with R-2/R-adj(2) equal to 0.99 and 0.74, respectively for MOPP, then for MOKP 0.90 and 0.73. Finally, the analysis of variance (ANOVA), confirmed that MOPP and MOKP had a high-efficiency adsorbent capacity with the MOPP as the best biosorbent than MOKP and that the chosen model is valid. The two materials could be adopted as efficient and cost-effective adsorbents.

Automated summary

In recent years, researchers have been exploring the use of biomaterials from various sources for wastewater treatment. This study focuses on using Moringaoleifera pods and kernels powder for removing methylene blue dye from water. The adsorption process follows the pseudo-second-order model, and the adsorbents were characterized using FT-IR, XRD, and SEM. The optimization process determined the optimal conditions for MOPP and MOKP, achieving high removal efficiencies of 98.12% and 96.94% respectively. The chosen model was validated by experimental data, and ANOVA confirmed the high-efficiency adsorbent capacity of the materials.