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

Abstract

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, K2CO3 and K2C2O4. The optimum mixture composition was 2.51\xa0g of KOH, 0.49\xa0g of K2CO3 and absence of K2C2O4, generating an optimized AC (ACop) with SBET value equals to 1984\xa0m2 g-1. The results herein obtained show that low amounts of K2CO3 can catalyze the pore development in the presence of KOH, increasing the surface area. Furthermore, the fractal dimensions of ACop 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 ACop has different oxygenated molecular fragments, which agrees with the pHPZC value (5.05). The ACop was applied in the adsorption of rhodamine B (RhB) and metformin (Met) in both binary and monocomponent systems. The simultaneous adsorption at 30\xa0°C reveals that the adsorption capacity of RhB is 630.94\xa0mg\xa0g-1, while for Met the value is 103.83\xa0mg\xa0g-1.