Remediation of methylene blue from aqueous medium using a nanosilica-Ricinodendron heudelotii shell-derived composite: Sorbent design and process optimization by DOE

A novel inorganic–organic eco-friendly composite based on Ricinodendron Heudolotii shells and rice husk derived nanosilica labeled Ns-RHS was synthesized and used for the adsorptive removal of Methylene blue (MB). The composite was characterized using XRD, TGA-FTIR and SEM analysis. Taguchi's methodology has been used to find optimum levels of parameters for the adsorption of MB. Significant adsorption parameters are the initial concentration (C 0 ), contact time (t) and pH of the adsorption capacity (Qe). Average values of adsorption capacities and S/N (Signal-to-Noise) ratio for each parameter at three different levels have been obtained using L9 Orthogonal Array. The initial dye concentration is found to be the most significant parameter with a contribution of 46.71%, and the contact time has a contribution of 20.53%). pH is found to be the least significant parameter with a contribution of 13.97%. The optimized levels of parameters are found to be A 3 , B 3 and C 2 . The predicted and characterized values of the dye adsorbed (Qe) on Ns-RHS at optimized levels were found to be 95.90 and 96.82 mg/g respectively. Ns-RHS powder is then a very promising adsorbent for MB removal.