Optimization of Sibipiruna activated carbon preparation by simplex-centroid mixture design for simultaneous adsorption of rhodamine B and metformin.

The present paper reports the application of augmented simplex-centroid mixture design to obtain a high BET surface area activated carbon using as reactants KOH, KCO and KCO. The optimum mixture composition was 2.51 g of KOH, 0.49 g of KCO and absence of KCO, generating an optimized AC (AC) with S value equals to 1984 m g. The results herein obtained show that low amounts of KCO can catalyze the pore development in the presence of KOH, increasing the surface area. Furthermore, the fractal dimensions of AC are greater than 2.72, indicating the material has a complex pore structure with irregularities self-similar upon variations of resolution, as seen by SEM images. The TPD curves showed that the AC has different oxygenated molecular fragments, which agrees with the pH value (5.05). The AC was applied in the adsorption of rhodamine B (RhB) and metformin (Met) in both binary and monocomponent systems. The simultaneous adsorption at 30 °C reveals that the adsorption capacity of RhB is 630.94 mg g, while for Met the value is 103.83 mg g.